CA2201886A1 - Morphine and codeine derivatives for use in therapy - Google Patents

Abstract

A compound of formula (I) wherein R1 = H (morphine analogue), CH3 (codeine analogue), R2 = H, alkyl group of 1 to 4 carbon atoms, allyl, cyclopropylmethyl, R3 = a group (A), -O-CH2-R4 (ether), -O-COCH = CHR4 (cinnamate), R4 = (B), wherein X1, X2, X3, X4 and X5 which may be the same or different are separately selected from H, alkyl of 1 to 4 carbon atoms, NH2, NO2, alkoxy group of 1 to 4 carbon atoms, hydroxy, halogen, N-alkyl, group of 1 to 4 carbon atoms, morpholine, or a group COR5 wherein R5 is H, OH, O-alkyl where alkyl is from 1 to 4 carbon atoms, or one of X1 and X2, X2 and X3, X3 and X4 or X4 and X5 together with an alkylene group optionally interrupted by O, S or N of up to 5 atoms in length complete a ring and a pharmaceutically acceptable salt thereof for use in therapy.

Description

~20 1 ~86 0 96/16063 PCTIGB9~;102712 MORPHINE AND CODEINE DERIVATIVES FOR USE IN THERAPY
Fiçld of the invention This invention is in the field of novel morphine-6-glu~iulull~L~ and 5 codeine-6-glucuronate analogues and their use in therapy as opioid analgesic agents.
Rn^l~round to the invention D~r~ of the prior art While opium has been used for ce~t--ries to control pain, it was only in the mid-1 920's that the structure of the principle active alkaloid, morphine was established.
The opioid analgesic morphine is often the drug of choice for te~rnin~llyill cancer patients and in other cases of severe pain. Although traditionally used by the ;~ r route, other routes of ~tlmini~tration, particularly the oral ~-lmini~tr~tion of morphine is becoming more widespread. One of the drawbacks however to the use of orally ~lmini~tered morphine is a variable absorption and metabolism of the morphine byl S individual patients due to extensive hepatic metabolism and poor bio-availability which results in an unpredictive effectiveness. Additionally, it is well known that the theld~uLic use of morphine gives rise to various side effects such as l~s~ lol y depression, nausea, vomiting, abuse potential etc.
Despite these disadvantages, morphine is still often the analgesic of choice and its use is generally ill~;l.,asillg.
It has been reported that metabolites of morphine such as morphine-6-glucuronide(M6G) may be as or more active than the parent drug with less chance of side effects.
Osborne et al.(1988), The Lancet, April 6, p 828 has (1i~clle~e~1 the use of morphine-6-glucuronide as a drug substance in its own right.
In ~nim~l~, morphine-6-glucuronide is a more potent antinociceptive agent than morphine, the exact relationship depending on the test model and route of ~lmini~tration~
but always being more potent when ~rlmini~tered by the intrathecal route. Nevertheless, the physico~h~mil~l ch~r~rt~ristics of morphine-6-glucuronide restricts any potential oral ~rlmini~tration and hence reduces its clirical usefulness. It is thus desirable to identify 22~1 886 WO 96/16063 P~TtGB95/02712 other derivatives of morphine which preserve the pharmokinetic advantages of morphine-6-glucuronide but with improved oral bioavailability for their plOp~ - lies as analgesic agents.
S--mm~ry of the jnvention The inventors have i~l~ntified and synthe~i~e(l 6-sub~LiLuL~d derivatives of morphine 5 and codeine, another opioid analgesic compound.
Accordingly the invention provides a compound of Formula I below ~NR2 ~_~

wherem 15 R1 = H (morphine analogue), CH3 (codeine analogue) R2 = H, alkyl group of 1 to 4 carbon atoms, allyl, cyclopropylmethyl o R3 = a group -O-C-R4 O-CH2-R4 (ether) -O-COCH = CHR4 (cinn~m~tP.) X~X2 wherein R4 = ~X3 Xs X4 ~ ~201 886 ~10 96/16063 PCT/GB95/02712 whe.eill Xl, X2, X3, X4 and Xs which may be the same or ~ L are s~ ely selected from H, an alkyl group of l to 4 carbon atoms, NH2, NO2, alkoxy group of l to 4 carbon atoms, hydroxy, halogen, N-alkyl group of l to 4 carbon atoms, morpholine, a group CORs wherein Rs is H, OH, O-alkyl where alkyl is from l to 4 carbon atoms, or one of v S Xl and X2, X2 and X3, X3 and X4 or X4 and Xs together with an alkylene group , optionally h~L~llul~led by O, S or N of up to 5 atoms in length complete a ring and a ph~rrn~e~ltically acceptable salt thereof for use in therapy.
I~es~ ;ution of the p~ ~fe. . ~d embodim~s Morphine and other traditional opiate analgesics act through opioid ,u receptors to induce analgesia together with the well known side effects of addiction, lc~il~oly depression etc., whilst opioid lC rece~lol~ may mediate psychomimetic and other effects.
It is known that the opioid rece~tor profile of morphine and morphine-6-glucuronide differ.
The compounds of the present invention exaggerate this ~ ellce resulting in colll~ lds which have an equivalent ~-affinity, a higher ~-affinity and a lower lc-affinity. Hence the l 5 compounds of the invention are more beneficial than M6G, by being as well as more bio-available, having reduced lc-mediated side effects.
Of all the compounds in the above Formula I the ~l~r.,.l~_d morphine (Rl = H) and codeine (Rl = CH3) derivatives are those wherein R2 is H, an alkyl group of l to 4 carbon atoms, preferably methyl or allyl (thus forming nalorphine-type derivatives). R3 is preferably a grouping o and R4 is preferably a group ~X3 ~<

wherein Xl, X2, X3, X4 and Xs are H, NH2, NO2, OH, halogen or CORs where Rs is ~20 1 886 OH. In all cases, when the compound of the invention contains an alkyl group, this may be linear or branched.
In the above compounds preferably at least 3 of Xl, X2, X3, X4 and Xs are H.
Where there are substitll~nt~ the substituents may be in the ortho, meta or para positions 5 but where there is only one substituent preferably this is in the ortho position, more preferably in the para position and where there is more than one sl-hstit~lent one is in the para position. Where there is an alkylene ring formed by two of Xl, X2, X3, X4 and Xs, preferably this is between X2 and X3 or X3 and X4. It may be, for example a group -O-CH2-0.
Of all the compounds embraced by Formula I, the pler~ll. d compounds are morphine or codeine-6-nitroben7n~tt?, morphine or codeine-6-hydroxyb~n7O~tr and morphine or codeine-6-phth~l~t~
As stated above, the morphine-6-glucuronide analogues and codeine-6-glucuronide analogues are believed to function as analgesic agents. Thus, the invention further provides a ph~rm~reutical composition which comprises a compound of Formula I together with a ph~rm~relltically-acceptable diluent or carrier, preferably one which is sterile and pyrogen free. As indicated, the compounds may be formul~te~l as salts formed with physiologically acceptable inorganic or organic acids and when so form~ tç(l it is pl~rt;ll~ d to use mçth~nr sulphonic acid, isethionic acid, tartaric acid or another solubilising acid.
The compounds of Formula I may be formlll~t~d singly or as a lllixlul~; of two or more compounds for use as ph~rm~relltic~l~ by a variety of methods. The composition may be in a form suitable for oral ~-lmini~tration as a tablet or capsule or liquid medicine, a suppository or in a form suitable for palellleldl a~lmini~tration by for example injection or infusion, as a sterile solution or infusion. The compounds may be formul~tçd for controlled delayed release, e.g. in tablets and suppositories.
Ph~rm~seutical compositions co.~l;-il-;..p compounds of Formula I may be formul~t~?-l in unit dosage form, i.e. in the form of discrete portions, each cont~ining a u~it dose or a multiple or sub-multiple of a unit dose.
Without limitations to dosages it may be stated that the compound of Formula I will 30 normally be ~lmini~t~red to a warm-blooded animal at a dose within the range for example in man of 1-100 mg orally more preferably 5-50 mg orally or by intramuscular or - ~201 886 subcutaneous injection up to 6 times daily. As a general guide, the dosage used will be equivalent to or slightly less than dosages o~ morphine or codeine which are well char~c~r~ced and known to a person skilled in the art. It will be appreciated however that the specific dosage for a patient will depend on how much pain that patient is experiencing 5 and actual dosages in this case will be leterrnin~(l by the ~ n~in~ medical staff.
It is believed that most of these compounds are novel, thus, according to a further aspect of the invention there is provided a compound of Formula II.

~ NR2 ~'~

1 5 wherein Rl = H (mo~phine analogue), CH3 (codeine analogue) R2 = H, alkyl group of 1 to 4 carbon atoms, allyl, cyclopropylmethyl o R3 = a group -O-C-R4 -O-CH2-R4 (ether) -O-COCH = CHR4 (cinn~nn~te) wherein R4 = X~X2 ~X3 wherein Xl, X2, X3, X4 and Xs which may be the same or different are se~ Lely selected - ~20 1 886 from H, an alkyl group of 1 to 4 carbon atoms, NH2, NO2, alkoxy group of 1 to 4 carbon atoms, hydroxy, halogen, N-alkyl group of 1 to 4 carbon atoms, morpholine, a group CORs wherein Rs is H, OH, O-alkyl where alkyl is from 1 to 4 carbon atoms, or one of Xl and X2, X2 and X3, X3 and X4 or X4 and Xs together with an alkylene group 5 optionally hlt~ d by O, S or N of up to 5 atoms in length complete a ring with the proviso that not all Xl, X2, X3, X4 and Xs are hydrogen and ph~rm~celltic~lly acceptable salts thereof.
The novel morphine-6-glucuronide analogues and codeine-6-glucuronide analogues of the invention may be pl~d,ed by any process known to be applicable to the ~ ,~dlion 10 of chemically related compounds. Accordingly, such processes form a further feature of the invention.
In particular, the codeine-6-b.on7O~t~ derivatives for example may be synth~eiee-l from codeine by reaction with the ~plol,.;ate acid anhydride or acid chloride in the ~c;sellce of dimethyl~mminll pyridine (DMAP). Protection of the 3-hydruxy functions of 15 morphine as the 3-t-butyldimethylsilyl (3-t-BDMS) ether allows synthesis of the corresponding morphine analogues after deprotection of the 3-t-BDMS-6-esters with tetrabutylammonium fluoride (TBAF).
As a further example morphine and codeine-6-ethers may be prepared by the reaction of codeine or similarly protected morphine with the ap~lu~liate alkyl chloride in 20 the presence of sodium hydride in THF.
According to a further aspect of the invention there is provided a method of alleviating pain in an individual in need of such tre~tment which comprises ~lminietering to said individual a th~ldl,~,uLically effective amount of a compound of Formula I or II as defined hereinbefore. The invention also provides the use of a compound of Formula I or 25 II as defined hereinbefore in the m~mlf~ture of a novel medicament for use in alleviating pain.
The invention is illustrated by the following Examples in which Figure 1 referred to illustrates pathways for the synthesis of codeine analogues;
Figure 2 referred to illu~Lldles pathways for the synthesis of morphine analogues.

F~ ~ rr~M96~ 115 2 2 0 ~ 8 8 6 ` . . . .
EXAMPLE 1: S~THESIS OF CODEINE ANALOGUES OF M6G
The syntheses of the compounds described in this Example are shown schematicallyin Figure 1.

S Preparation of 7,8-Didehydro-4,5a-epo~y-3-methoxy-17-methyl-6a-succinyloxy-morphinan (1) A mixture of codeine (1 g, 3.34 mmol) and succinic anhydride (2g, 20 mmol) in pyridine (5 cm3) was refluxed for 1 hr. The hot reaction r~uxture was poured onto ice and the resulting white precipitate collected on a filter. The precipitate was washed with cold water. Cry t~ tion from DCM-petroleum ether gave the ester (1) (240 mg, 18%) m.p. 154-6C; vmax(nujol)/cm~1 3432 (OH), 1720 (C=O ester), 1632 (C=O acid);
oH(CDCl3) 1.89 (1 H, d, J 13.5, 15e-H), 2.39-2.79 (11 H, m, NMe, 16-H2, 19-H2, 20-H2, 10a and lSa-H), 3.01 (1 H, d, J 19, 10~-H), 3.11 (l H, t, J 2.5, 14-H), 3.76 (1 H, q, J 3, 9-H),3.86(3H,s,OMe),5.15(1 H,d,J6.5,5-H),5.28(2H,m,6and8-H),5.60(1 H,d, J 10, 7-H), 6.55 and 6.68 (2 H, ABq, 1 and 2-H); m/z 399 (M+ 13%) 299(100), 282(22), 229(29), 188(14), 162(31), 124(27), 70(17), 56(56), 42(49). -Preparation of 6a-(2-Carboxybenzoylo~y)-7,8-didehydro-4,5a-epoxy-3-methoxy-17-methyl-morphinan (2) A ~ e of codeine (1 g, 3.34 mrnol) and phthalic anhydride (2 g, 13.5 rnrnol) in pyridine (S cm3) was refluxed for 1 hour. The hot reaction llli~Lul~, was poured onto ice and the resulting white precipitate collected on a filter. The ~re.,i~iL~l~; was washed with cold water Cryst~ tion from DCM-petroleum ether gave the ester (2) (2.67 g, 88%)m.p. 227-8C (decomp);
vmax(nujol)/cm~l 3417 (OH), 1713 (C=O ester), 1608 (C=O acid); H (CDCl3) 1.98 (1 H, d, J 13.5, 15e-H), 2.68-2.97 (7 H, m, NMe, 10a, 15a, 16-H and OH), 3.07 (1 H, d, J 19, 10,B-H), 3.44 (1 H, d, J 7, 16-H), 3.59 (1 H, t, J 2.5, 14-H), 3.85 (4 H, m, OMe and 9-H), 5.44 (3 H, m, 5, 6 and 8-H), 5.80 (1 H, d, J 8.5, 7-H), 6.61 and 6.74 (2 H, ABq, 1 and 2-H), 7.37 (1 H, t, J 7.5, 21-H), 7.51 (1 H, t, J 7.5, 22-H), 7.67 (1 H, d, J 7.5, 20-H), 8.04 (lH, d, J 7.5, 23-H); C 21.40, 32.09, 36.84, 40.80 (NMe), 40.96, 47.31, 56.99 (OMe), 60.11, 67.66, 87.38, 115.40,119.88, 122.83, 126.79, 127.29, 127.90, 129.75, A~I~N5~D S~

~ 2 0 ~ 88 ~
, .

29.98,130.22,131.16,131.39,132.07,143.26,146.81,166.6~,175.83;
m/z 447 (M+) 299(100), 282(10), 229(14), 148t7), 124(11), 104(33), 76(19).
[FAB-MS, Found (M+H+): 448.1752. C26H26NO6 requires 448.1760].

S Preparation of 6a-Benzoyloxy-7,8-didehydro-4,5a-epoxy-3-methoxy-17-methyl-morphinan (3) To a solution of codeine (300 mg, 1 mmol) in pyridine (3 cm3), under nitrogen, was added benzoyl chloride (0.35 ml, 1 mmol) and the reaction stirred at room ten~ Lu for 4 hours. DCM (10 ml) was added and the solution washed with a 5% CuSO4 solution and water, dried (Na2S04) and evaporated under reduced IJles~ . The crude product was purified by column chromatography (elution with 5% MeOH in DCM) to give the ester (3) (295 mg, 73%).
Alternatively a llli~lUlC; of codeine (300 mg, 1 mmol), benzoic acid (122 mg, 1 mmol) and DMAP (122 mg, l mmol) in DCM was stirred for I hour at 0C, the flask being fitted with a calcium chloride guard tube. DCC (230 mg, 1.1 mmol) was added and the solution, which was stirred at 0C for S min before being allowed to warm up to room temperature, followed by stirring for a filrther 3 hours. The reaction mixture was washed successively with dilute HCI/water/bicarbonate/water, dried (MgSO4) and evaporated under reduced pressure. The crude product was purified by column chl.3r,lalography (elution with 5% MeOH in DCM) to give the ester (3) (275 mg, 68%).
Recryst~ tion in each case from DCM-petroleum ether gave crystals m.p. 130-132C; vmax(nujol)/cm~l 1717 (C=O ester); ~H(CDC13) 1.91 (1 H, d, J 12.57 15e-H), 2.12 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.37 (2 H, m, 10a and 16-H), 2.48 (3 H, s, NMe), 2.65 (1 H, dd, J 12.5, 4, 16-H), 2.86 (1 H, t, J 2.5, 14-H), 3.06 (1 H, d, J 18.5, 10~-H),3.42(1 H,q,J3,9-H),3.72(3H,s,OMe~,5.20(1 H,d,J6.5,5-H),5.47(2H,m, 6 and 8-H), 5.78 (1 H, d, J 10, 7-H), 6.55 and 6.67 (2 H, ABq, 1 and 2-H), 7.43 (2 H, t, J 8, 21 and 23-H), 7.55 (1 H, t, J 8, 22-H), 8.09 (2 H, d, J 8, 20 and 24-H); ~c 21.36, 35.09, 40.39, 42.50, 42.85 (NMe), 46.63, 56.79 (OMe), 59.08, 68.40, 87.95, 114.59, 119.13, 126.66, 128.13, 128.57, 129.31, 129.80, 130.63, 132.91, 142.10, 146.70, 165.92;
m/z 403 (M+, 53%) 282(28), 266(23), 229(14), 155(15), 122(31), 105(100), 77(51).(Found M+, 403.1795. C2sH2sNO4 requires 403.1783).

2201 ~86 ~IO 96/16063 . PCT/GB9//02712 Preparation of 7,8-Didehydro-4,5a-epoxy-6a-(4-fluorol)e..z~loxy)-3-methoxy-17-methyl-morphinan (4 X=F in Figure 1) To a solution of codeine (300 mg, I mmol) in pyridine (3 cm3), under nitrogen, was added p-fluorobenzoyl chloride (0.35 cm3, 477 mg, 3 mmol) and the reaction stirred at 5 room temperature for 10 min~ltPs CHCl3 was added and the solution washed successively with dilute HCl/water/bicarbonate/water, dried (MgS04)7 and evaporated under reduced ,S~Ulc;. The crude product was purified by column chromatography (elution with 5%
MeOH in CHCl3) to give the ester (4 X=F in Figure 1) (403 mg, 95%). Recry~t~ tion from DCM-petroleum ether gave crystals m.p. 136-39C; vmax(nujol)/cm~1 1717 (C=O ester); ~H(CDCl3) 1.92 (lH, d, J 12.5, l5e-H), 2.16 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.42 (2 H, m, 10~ and 16-H), 2.S2 (3H, s, NMe), 2.75 (1 H, dd, J 12.5, 4, 16-H), 2.92 (1 H, t, J 2.5, 14-H), 3.08 (1 H, d, J 18.5, 10~-H), 3.53 (1 H, q, J 3, 9-H), 3.72 (3 H, s, OMe), 5.20 (1 H, d, J 6.5, 5-H), 5.43 (1 H, m, 6-H), 5.51 (1 H, d, J 10, 8-H), 5.77 (1 H, d, J 10, 7-H), 6.58 and 6.68 (2 H, ABq, 1 and 2-H), 7.11 (2 H, m, 21 and 23-H), 8.10 (2 H, m, 20 and 24-H); ~C 20.63, 34.82, 39.98, 42.41, 42.60 (NMe), 46.60, 56.74 (OMe), 59.04, 68.41, 87.85, 114.49, 115.24, 115.59, 119.37, 126.36, 128.69, 129.26, 130.49, 132.43, 132.58, 142.30, 146.76, 165.05, 167.88; rn/z 421 (M+, 53%) 282(28), 266(23), 229(14), 155(15), 122(31), 105(100), 77(51).
(Found M+, 421.1689. C2sH24NFO4 requires 421.1725).
Preparation of 6a-(4-Chlorol~ loxy)-7,8-didehydro-4,5a-epoxy-3-methoxy-17-methyl-morphinan (5 X=CI in Figure 1) To a solution of codeine (300 mg, 1 mmol) in pyridine (3 cm3), under nitrogen, was added p-chlorobenzoyl chloride (0.38 ml, 527 mg, 3 mmol). The reaction mixture was stirred at room t~ d~UI~ for 10 min. EtOAc was added and the solution washed sllcce~ively with dilute HCl/water/bicarbonate/water, dried (MgSO4), and evaporated under reduced pressure. The crude product was purified by column chromatography (elution with 1 0% MeOH in CHCl3) to give the ester (5 X=CI in Figure 1) (31 5 mg, 72%).
Recryst~ tion from DCM-petroleum ether gave crystals m.p. 165-67C;
`'max (CHCl3) cm~l 1719 (C=O ester); ~H(CDC13) 1.91 (1 H, d, J 12.5, 15e-H), 2.11 (1 H, dt, J 12.5, 5, 5, l5a-H), 2.3~ (2 H, m, 10~ and 16-H), 2.49 (3 H, s, NMe), WO 96/16063 ~ 2 ~ 1 8 8 6 PCT/GB95102712 2.65 (1 H, dd, J 12.5, 4, 16-H), 2.87 (1 H, t, J 2.5, 14-H), 3.07 (1 H, d, J 18.5, 10~H), 3.46(1 H,q,J379-H),3.72(3H,s,OMe),5.19(1 H,d,J6.5,5-H),5.43(1 H,m,6-H), 5.50 (1 H, d, J 10,8-H), 5.76 (1 H, d, J 10, 7-H), 6.57 and 6.67 (2 H, ABq, 1 and 2-H), 7.41 (2 H, d, J 8, 21 and 23-H), 8.02 (2 H, d, J 8, 20 and 24-H); ~c 20.63, 35.30, 40.59, 42.62, 43.01, (NMe), 46.70, 56.74 (OMe), 59.12, 68.68, 87.93, 114.35, 119.31, 126.95, 128.49, 128.60, 128.81, 129.75, 130.73, 131.33, 139.47, 142.18, 146.18, 146.52, 165.20;
m/z439 and437 (M+, 23 and 63%) 302(8), 300(24), 282(58), 229(26), 155(12), 141(33), 139(100), 111(38), 94(9), 59(44), 42(54).
(Found M+, 439.1364 and 437.1394. C2sH24NClO4 requires 439.1383 and 437.1397).
Preparation of 6a-(4-Bromobenzoyloxy)-7,8-didehydro-4,5a-epoxy-3-methoxy-17-methyl-morphinan (6 X=Br in Figure 1) To a solution of codeine (300 mg, 1 mmol) in pyridine (3 cm3), under nitrogen, was added p-bromobenzoyl chloride (1.1 g, 5 mmol) and a catalytic amount of DMAP. The reaction ~ Lulc was stirred at room ~el~ dLulc for 10 minllt.os CHC13 was added and the solution washed successively with dilute HCl/water/bic~l,ol,~Le/water, dried (MgSO4), and evaporated under reduced ~lCS~u,c. The crude product was purified by column chromatography (elution with 5% MeOH in CHCl3) to give the ester (6 X=Br in Figure 1) (441 mg, 92%). Recryst~ tion from DCM-petroleum ether gave crystals m.p. 177-80C; vmax(CHCl3)/cm~l 1719 (C=O ester); ~H(CDCl3) 1.90 (lH, d, J 12.5,l5e-H), 2.11 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.37 (2 H, m, 10 and 16-H), 2.48 (3 H, s, NMe), 2.65 (1 H, dd, J 12.5, 4, 16-H), 2.85 (1 H, t, J 2.5, 14-H), 3.07 (1 H, d, J 18.5, 10~-H),3.44(1 H,q,J3,9-H),3.72(3H,s,OMe),5.19(1 H,d,J6.5,5-H),5.42(1 H,m, 6-H),5.51(1H,d,J10,8-H),5.76(1H,d,J10,7-H),6.57and6.67(2H,ABq,land 2-H), 7.58 (2 H, d, J 8, 21 and 23-H), 7.94 (2 H, d, J 8, 20 and 24-H); ~c 20.46, 35.14, 40.38, 42.54, 42.88 (NMe), 46.68, 56.74 (OMe), 59.10, 68.62, 87.84, 114.38, 119.34, 126.72, 128.16, 128.42, 128.92, 129.60, 130.63, 131.46, 131.60, 142.23, 146.66, 165.31;
m/z 483 and 481 (M+, 80 and 90%), 282(100), 346 and 344(25 and 27), 229(42), 185 and 183(76 and 83), 157(27), 105(34), 81(38), 59(52).
(Found M+, 483.0887 and 481.0716. C2sH24NBrO4 requires 483.0869 and 481.0889).

2201 8~6 ~o 96/16063 PcT/Gsg5l027l2 Preparation of 7,8-Didehydro-4,5a-epoxy-3-methoxy-17-methyl-6a-(4-nitrobenzoyloxy)-morphinan (7 X=NO2 in Figure 1 ) To a solution of codeine (300 mg, 1 mmol) in pyridine (3 cm3), under nitrogen was added p-nitrobenzoyl chloride (560 mg, 3 mmol) and the reaction stirred at room 5 lt~ d~ul~ for 4 hours. EtOAc was added and the solution washed with 5% CuSO4 solution/water, dried (MgSO4), and evaporated under reduced l,le~ . The crude product was purified by column chromatography (elution with 15% MeOH in CHC13) and TLC plates (run in CHC13/MeOH/NH40H) to give the ester (7 X=N02 in Figure 1) (283 mg, 63%). Recrystallisation from DCM-petroleum ether gave crystals m.p. 186-87C;
vmax(CHCl3)/cm~l 1722 (C=O ester); ~H(CDCl3) 1.90 (1 H, d, J 12.5, 15e-H), 2.08 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.34 (2 H, m, 10 and 16-H), 2.46 (3 H, s, NMe), 2.61 (1 H, dd, J 12, 4, 16-H), 2.83 (1 H, t, J 2.5, 14-H), 3.07 (1 H, d, J 18.5, 10~-H), 3.40 (1 H, q, J 3, 9-H), 3.71 (3 H, s, OMe), 5.20 (1 H, d, J 6.5, 5-H), 5.47 (1 H, m, 6-H), 5.55 (1 H, d, J 10, 8-H), 5.76 (1 H, d, J 10, 7-H), 6.58 and 6.67 (2 H, ABq, 1 and 2-H), 8.27 (4 H, m, 20, 21, 23 and 24-H); ô 20.30, 35.35, 40.66, 42.59, 43.09, (NMe), 46.74, 56.49 (OMe), 59.13, 69.17, 87.57, 113.86, 119.46, 123.40, 127.03, 127.80, 130.20, 130.60, 131.07, 142.18, 146.44, 150.59, 164.22; m/z 448 (M+, 84%), 311(20), 282(82), 229(25), 152(16), 104(44), 92(20), 76(42), 59(39), 50(100), 44(58).
(Found M+, 448.1607C2sH24N2O6 requires 448.1634).
Preparation of 7,8-Didehydro-4,5a-epoxy-3-methoxy-6a-(4-methoxybenzoyloxy)-17-1nethyl-morphinan (8 X=OMe in Figure 1) To a solution of codeine (300 mg, 1 mmol) in pyridine (3 cm3), under nitrogen, was added p-anisoyl chloride (0.45 ml, 513 mg, 3 mmol) and the reaction stirred at room te~ JcldLul~; for 10 minl-tes EtOAc was added and the solution washed successively with dilute HCl/water/bicarbonate/water, dried (MgSO4), and evaporated under reduced pressure. The crude product was purified by column chromatography (elution with 5%
MeOH in DCM) to give the ester (8 X=OMe in Figure 1) (426 mg, 98%). Recryst~ tion from DCM-petroleum ether gave crystals m.p. 174-76C; vmax(CHCl3)/cm~l 1711 (C=O
ester); ôH(CDC13) 1.90 (1 H, d, J 12.5, 15e-H), 2.09 (1 H, dt, J 12, 5, 5, 15a-H), 2.36 (2 H,m,lOaandl6-H),2.48(3H,s,NMe),2.62(1H,dd,J12,4,16-H),2.83(1H,t,J2.5, WOg6/16063 2 2 3 1 8 8 6 PCT/GB95/02712 14-H), 3.06 (1 H, d, J 18.5, 10~-H),3.42 (1 H, q, J 3, 9-H), 3.44 (3 H, s, OMe), 3.74 (3 H, s, OMe), 5.18 (1 H, d, J 6.5, S-H), 5.41 (1 H, m, 6-H), 5.48 (1 H, d, J 10, 8-H), 5.76 (1 H, d, J 10, 7-H), 6.55 and 6.66 (2 H, ABq, 1 and 2-H), 6.92 (2 H, d, J 9, 21 and 23-H), 8.04 (2 H, d, J 9, 20 and 24-H), ~C 20.49, 35.28, 40.54, 42.69, 42.94 (NMe), 46.63, 55.42 (OMe), 57.02 (OMe), 59.05, 68.34, 88.32, 114.82, 119.19, 122.41, 126.97, 128.85, 129.42, 130.90, 131.98, 142.16, 146.78, 163.47, 165.77; m/z 433 (M+, 43%), 282(20), 229(12), 152(14), 135(100), 77(16), 44(11).
(Found M+, 433.1915 C26H27NOs requires 433.1889).

Preparation of 7,8-Didehydro-4,5a-epoxy-3-methoxy-6a-(3,4-methylenedioxybenzoyloxy)-17 m~ lh~l-morphinan (9) To a solution of codeine (200 mg, 0.67 mmol) in DCM (2 cm3) at 0C, under nitrogen, was added piperonylic acid (333 mg, 2 mmol) and DMAP (82 mg, 0.67 mmol) and the solution was stirred for 30 min. DCC (152 mg, 0.74 mmol) was added and the reaction flask fitted with a calcium chloride guard tube. After stirring for 5 minl~teC at 0C, the reaction mixture was allowed to warm up to room t~lllp.,~d~llre and stirred overnight.
The reaction mixture was filtered, washed with water/bicarbonate, dried (MgSO4) and evaporated under reduced ~le;~:~Ult;. The crude product was purified by column chromatography (elution with 10% MeOH in CHC13) to give the ester (9) (195 mg, 65%).
Recryst~ tion from DCM-petroleum ether gave crystals m.p. 63-5C;
~Jmax(CHCl3)/cm~1 1711 (C=O ester); ~H(CDC13) 1.90 (1 H, d, J 12.5, 15e-H), 2.11 (1 H, dt, J 12, 5, 5, 15a-H), 2.37 (2 H, m, 10a and 16-H), 2.46 (3 H, s, NMe), 2.64 (1 H, dd, J 12, 4, 16-H), 2.84 (1 H, t, J 2.5, 14-H), 3.06 (1 H, d, J 18.5, 10~-H), 3.44(1 H,q,J3,9-H),3.76(3H,s,OMe),5.17(1 H,d,J6.5,5-H),5.41 (1 H,m,6-H), 5.50 (1 H, d, J 10,8-H), 5.75 (1 H, d, J 10, 7-H), 6.03, (1 H, s, CH~), 6.56 and 6.67 (2 H, ABq, 1 and2-H),6.84(1 H,d,J8,23-H),7.52(1 H,d,J 1.5,20-H),7.70(1 H,dd,J8, 1.5, 24-H); m/z 447 (M+, 40%) 310(17), 282(25), 229(13), 165(29), 149(100), 121 (20), 91 (8), 65(25), 42(21). (Found M+, 447.1679. C26H2sNO6 requires 447.1682).

2201 ~86 Ivo 96/16063 PCT/GB95/02712 Preparation of 6a-(4-t-Butyldi~ ylsilyloxybenzovloxy)-7,8-didehydro-4,5a-epoxy-3-methoxy-17-methyl-morphinan (10) Freshly prepared p-t-BDMS-oxy benzoic acid (500 mg, 1.98 mmol) in DCM
(5 cm3),under nitrogen, was treated with oxalyl chloride (630 mg, 0.43 cm3, 5 mmol).
S Effervescence implied formation of the acid chloride. On completion of the reaction, after 20 minlltes, benzene (5 cm3) was added and all solvents removed under reduced ~ ule.
To the acid chloride residue, under nitrogen, was added a solution of codeine (200 mg, 0.67 mmol) in pyridine (3 cm3) and the reaction stirred at room temperature for 2 hours. EtOAc was added and the solution washed with dilute HCl/waterlbicarbonate/water, dried (MgSO4) and evaporated under reduced ~l~;S~u~t;. The crude product was purified by column chromatography (elution with 5% MeOH in DCM) to give the ester (10) (293 mg, 82%). Recryst~ tion from DCM-petroleurn ether gave crystals m.p. 102-5C; vmax(nujol)/cm~l 1709 (C=O ester); ~H(CDCl3) 0.22 (6 H, s, SiMe2), 0.98 (9 H, s, SiCMe3), 1.93 (1 H, d, J 12.5, l5e-H), 2.21 (1 H, dt, J 12.5, 5, 5, l5a-H), 2.47 (2 H, m, 10~ and 16-H), 2.56 (3 H, s, NMe), 2.83 (1 H, dd, J 12, 4, 16-H), 2.99(1 H,t,J2.5, 14-H),3.08(1 H,d,J 18.5, l0~-H),3.60(1 H,q,J3,9-H),3.73(3H, s, OMe), 5.20 (1 H, d, J 6, 5-H), 5.41 (1 H, m, 6-H), 5.48 (1 H, d, J 10, 8-H), 5.78 (1 H, d, J 10, 7-H), 6.57 and 6.68 (2 H, ABq, 1 and 2-H), 6.86 (2 H, d, J 8.5, 21 and 23-H), 7.98 (2 H, d, J 8.5, 20 and 24-H); m/z 533 (M+, 77%) 396(25), 282(57), 235(100), 229(25), 195(52), 149(14), 121(44), 91(14), 73(59), 59(18), 42(34).
(Found M+, 533.2579. C31H3gNOsSi requires 533.2597).

Preparation of 7,8-Didehydro-4,5a-epoxy-6a-(4-hydroxybenzoyloxy)-3-methoxy-17-methyl-morphinan (11) To a solution ofthe codeine ester 10 (100 mg, 0.19 mmol) in THF, under nitrogen,at 0C was added TBAF-l M solution in THF (1 cm3). After stirring for 5 minlltes the - reaction was allowed to warm up to room temperature and stirred for a further 2 hours.
EtOAc was added and the solution washed several times with water, dried (Na2S04) and evaporated under reduced ~Jres~ul~. The crude product was purified by columnn chrom~toEr~phy (elution with 10% MeOH in CHCl3) to give the ester (11) (48 mg, 61%).
Recrystallisation from DCM-petroleum ether gave crystals m.p. 132-5C;

WO96/16063 ~ ~2 0 ~ 8 8 ~ PCT/GB95/02712 vmax(nujol)/cm~l 3563 (OH), 1712 (C=O ester); 8H(CDC13) 1.91 (1 H, d, J 12.5, 15e-H), 2.15 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.41 (2 H, 10a and 16-H), 2.51 (3 H, s, NMe), 2.68 (1 H, m, 16-H), 2.89 (1 H, t, J 2.5, 14-H), 3.06 (1 H, d, J 18.5, 10~-H), 3.47 (1 H, q, J3,9-H),3.73(3H,s,Ome),5.19(1 H,d,J6,5-H),5.39(1 H,m,6-H),5.47(1 H,d,J 10, 8-H),5.78(1 H,d,J 10,7-H),6.56and6.67(2H,ABq, 1 and2-H),6.83(2H,d,J9,21 and 23-H), 7.95 (2 H, d, J 9, 20 and 24-H), m/z 419 (M+, 20%) 282(19), 229(7), 162(40), 138(32), 121(80), 94(36), 73(32), 65(30), 44(100).
(Found M+, 419.1749. C2sH2sNOs requires 419.1733).

EXAMPLE 2: SYNTHESIS OF MORPHINE ANALOGUES OF M6G
The synthesis of the compounds described in this Example is shown scht-- ~ti~llyin Figure 2 Preparation of 3-t-Butyldimethylsilyloxy-7,8-didehy~lro-4,5a-epoxy-17-methyl-morphinan-6-ol (1) To a solution of morphine (2 g, 7 mrnol), in THF, under nitrogen, was added NaH-60% dispersion in mineral oil (310 mg, 7.75 mmol) and the reaction stirred for 1 hour.
tert-Butyldimethylsilyl chloride (1.27 g, 8.45 mmol) was added and the reaction stirred overnight. The mixture was filtered and THF removed under reduced pressure. The 20 residue was purified by column chromatography (elution with 15% MeOH in CHCl3).
A cream powder was obtained (1.445 g, 52%) m.p. 121-22C (lit. 122-123C);
vmax(nujol)/cm~l 3552 (OH), 1629; H (CDCl3) 0.16 (3 H, s, SiMe), 0.20 (3 H, s, SiMe), 0.98 (9 H, s, SiCMe3), 1.89 (1 H, d, J 12, l5e-H), 2.21 (1 H, dt, J 12.5, 5, 5, l5a-H), 2.43 (2 H, m, 10a and 16-H), 2.55 (3 H, s, NMe), 2.75 (1 H, dd, J 12.5, 4, 16-H), 2.89(1 H,t,J2.5, 14-H),3.04(1 H,d,J 18.5, 10~-H),3.50(1 H,q,J3.5,9-H),4.19(1 H, m, 6-H), 4.87 (1 H, d, J 6.5, 5-H),5.26 (1 H, d, J 10, 8-H),5.70 (1 H, d, J 10, 7-H), 6.50 and 6.60 (2 H, ABq, 1 and 2-H); m/z 503 (M+, 15%) 446(10),324(6), 266(9), 122(8), 105(100), 77(27), 57(16), 41(35). (Found M+, 503.2446. C30H37NO4Si requires 503.2492).

22~ 1 ~8~

~o 96/16063 PcT/Gss5/027l2 Preparation of 6a-Benzoyloxy-3-t-butyldimethylsilyloxy-7,8-did~ hy~lr~,-4,5a-epoxy-17-methyl-morphinan (2 X----H in the relevant part of Figure 2) To a solution of 3-t-BDMS-morphine (1) (300 mg, 0.75 mmol) in pyridine (3 cm3) with a little DMAP, under nitrogen, was added benzoyl chloride (0.5 cm3, 317 mg,2.25 mmol) and the reaction stirred at room t~ c.dLul. for 10 I.l;llllles. CHC13 was added and the solution washed successively with 5% CuSO4 solution/water, dried (MgSO4), and evaporated under reduced yles~ The crude product was purified by column chromatography (elution with 3% MeOH) in CH2C12) to give the ester (2 X=H in Figure 2) (336 mg, 89%) m.p. 133-5C; vmax(CHCl3)/cm~l 1717 (C=O); ~H (CDC13) 0.13 (6 H, s, SiMe2), 0.84 (9 H, s, SiCMe3), 1.93 (1 H, d, J 11, 15e-H), 2.33 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.56 (2 H, m, 10a andL 16-H), 2.64 (3 H, s, NMe), 2.95 (1 H, dd, J 12.5, 4, 16-H), 3.09 (2 H, m, 10~ and 14-H), 3.71 (I H, q, J 3.5, 9-H), 5.24 (1 H, d, J 6, 5-H), 5.44 (2 H, m, 6 and 8-H), 5.79 (1 H, d, J 10, 7-H), 6.51 and 6.62 (2 H, ABq, 1 and 2-H), 7.42(2H,t,J7.521 and23-H),7.56(1 H,t,J7.5,22-H),8.09(2H,d,J7,20and24-H).
Preparation of 3-t-Butyldimethylsilyloxy-7,8-didehydro-4,5a-epoxy-6a-(4-fluoro-benzoyloxy)-17-methyl-morphinan (3 X=F in the relevant part of Figure 2 ) To a solution of 3-t-BDMS-morphine (1) (300 mg, 0.75 mmol) in pyridine (3 cm3), under nitrogen, was added p-fluorobenzoyl chloride (0.3 cm3, 360 mg, 2.25 mmol) and the reaction stirred at room ~ Jc~dlul~ for 20 minlltes CHC13 was added and the solution washed s~-ccee~ively with 5% CuSO4 solution/water~ dried (MgSO4), and evaporated under reduced ~le;,~ . The crude product was purified by column chromatography (elution with 3% MeOH in CH2C12) to give the ester (3 X=F) (342 mg, 87%) m.p. 134-6C;
vmax(CHCl3)/cm~l 1717 (C=O ester); ~H (CDC13) 0.04 (6 H, s, SiMe2), 0.84 (9 H, s, SiCMe3), 1.90 (1 H, d, J 11, 15e-H), 2.24 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.52 (2 H, m, lOa and 16-H), 2.58 (3 H, s, NMe), 2.85 (1 H, dd, J 12.5, 4, 16-H), 3.01 (1 H, t, J 2.5, 14-H), - 3.08(1H,d,J18.510~-H),3.66(1H,q,J3,9-H),S.l9(lH,d,J6.5,5-H),5.39(1H,m, 6-H), 5.48 (1 H, d, J 10, 8-H), 5.76 (1 H, d, J 10, 7-H), 6.50 and 6.61 (2 H, ABq, 1 and 2-H),7.07and7.11(2xlH,d,J8.5,21and23-H),8.08and8.12(2xlH,d,J8.5,20and 24-H); ~C -4.85, 18.06, 21.11, 25.51, 34.56, 39.55, 42.16 (NMe), 42.71, 46.39, 58.90, 69.16, 87.79, 115.24, 115.59, 119.31, 121.71, 126.11, 128.80, 129.04, 130.11, 131.96, ~20 ~ 886 132.52, 132.52, 132.67, 137.76, 149.03, 163.86, 168.86, 168.12; m/z 521 (M+, 14%) 464(9), 382(5), 324(4), 284(5), 140(20), 123(1 00), 95(28), 73(21), 59(9), 42(1 1).
(Found M+, 521.2413. C30H36NFO4Si requires 521.2398).

S Preparation of 3-t-Butyldimethylsilyloxy-6a-(4-chlorol,ezu~loxy)-7,8-didehy~lr.,-4,5a-epoxy-17-methyl-morphinan (4 X=CI in the relevant part of Figure 2) To a solution of 3-t-BDMS-morphine (1) (300 mg, 0.75 mmol) in pyridine (3 cm3), under nitrogen, was added p-chlorobenzoyl chloride (0.3 cm3, 396 mg, 2.25 mmol) and the reaction stirred at room t~lllpeldLu.e for 5 minllte~ CHC13 was added and the solution washed sl~c~c~ively with 5% CuSO4 solution/water, dried (MgSO4), and evaporated under reduced ~l~S~ . The crude product was purified by column cl~ lldL~graphy (elution with 3% MeOH in CH2Cl2) to give the ester (4 XcCI) (381 mg, 94%) m.p. 119-21C;
vmax(CHCl3)/cm~l 1719 (C=O ester); ~H(CDCl3) 0.05 (6 H, s, SiMe2), 0.85 (9 H, s,SiCMe3), 1.84 (1 H, d, J 11, 15e-H), 2.05 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.34 (2 H, m, 10~
and 16-H), 2.45 (3 H, s, NMe), 2.57 (1 H, dd, J 12.5, 4, 16-H), 2.77 (1 H, t, J 2.5, 14-H), 3.04(1H,d,J18.5,10~-H),3.38(1H,q,J3.5,9-H),5.16(1H,d,J6.55-H),5.39(1H, m, 6-H), 5.48 (1 H, d, J 10, 8-H), 5.72 (1 H, d, J 10, 7-H), 6.47 and 6.58 (2 H, ABq, 1 and 2-H), 7.41 (2 H, d, J 8.5, 21 and 23-H), 8.01 (2 H, d, J 8.5, 20 and 24-H), ~c -4.78, 18.31.
21.46, 25.03, 32.76, 37.64, 40.86 (NMe), 41.56, 46.50, 59.50, 68.39, 86.77, 119.47, 122.11, 127.01,128.08,128.38,129.29,130.89,131.11,137.76,139.45,148.03,164.76; m/z539 and 537 (M+, 23 and 55%) 482(13), 480(34), 456(15), 413(13), 382(25), 324(18), 300(14), 266(14), 141(35), 139(91), 123(7), 94(10), 73(100), 59(36), 42(48).
(Found M+, 539.2070 and 537.2123. C30H36NClO4Si requires 539.2072 and 537.2102).
Preparation of 6a-(4-Bromol,~ u~loxy)-3-t-butyldim~lh~ oxy-7,8-didel.ydr~-4,5a-epoxy-17 Ihyl-morphinan (5 X=Br in the relevant part of Figure 2) To a solution of 3-t-BDMS-morphine (1) (300 mg, 0.75 mmol) in pyridine (3 cm3) with a little DMAP, under nitrogen, was added p-bromobenzoyl chloride (825 mg, 3.75 mmol) and the reaction stirred at room Lt;~ dLulc; for 20 mimlt~ CHCl3 was added and the solution washed successively with 5% CuSO4 solution/water, dried (MgSO4), and evaporated under reduced pressure. The crude product was purified by column 22U 1 ~86 chromatography (elution with 3% MeOH in CH2C12) to give the ester (5 X=Br) (315 mg, 72%) m.p. 137-8C; vmax(CHCl3)/cm~l 1719 (C=O ester); ~H (CDC13) 0.01 (3 H, s, SiMe), 0.04 (3 H, s, SiMe), 0.84 (9 H, s, SiCMe3), 1.87 (1 H, d, J 11, 15e-H), 2.15 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.40 (2 H, m, 10cc and 16-H), 2.47 (3 H, s, NMe), 2.72 (I H, dd, J
12,4, 16-H),2.88(1 H,t,J2.5, 14-H),3.06(1 H,d,J 18.5, 10~-H),3.50(1 H,q,J3,9-H),5.17(1H,d,J6.5,5-H),5.38(1H,m,6-H),5.48(1H,d,J10,8-H),5.73(1H,d,J10, 7-H), 6.49 and 6.59 (2 H, ABq, 1 and 2-H), 7.56 (2 H, d, J 8.5, 21 and 23-H), 7.95 (2 H, d, J 8.5, 20 and 24-H); m/z 583 and 581 (M+, 22 and 22%) 527(15), 525(14), 382(19),266(15), 202(29), 200(30), 185(96), 183(100), 155(31), 123(41), 105(33), 75(50), 73(62), 51(56), 41(58).
(Found M+, 583.1641 and 581.1603. C30H36NBrO4Si requires 583.1578 and 581.1597).
Preparation of 3-t-Butyl~ lLylsilyloxy-7,8-didehydro-4,5a-epoxy-17-methyl-6a-(4-nitrobenzoyloxy)-morphinan (6 X=N02 in the relevant part of Figure 2) To a solution of 3-t-BDMS-morphine (1) (150 mg, 0.37 mmol) in pyridine (5 cm3) with a little DMAP, under nitrogen, was added p-nitrobenzoyl chloride (210 mg, 1.13 mmol) and the reaction stirred overnight. EtOAc was added and the solution washed with 5% CuSO4 solution/water, dried (Na2S04) and evaporated under reduced pressure.
The crude product was purified by column chromatography (elution with 10% MeOH in CHCl3) to give the ester (6 X=NO2) (162 mg, 78%) m.p. 129-31C; vmax(nujol)/cm~l1718 (C=O ester); ~H (CDC13) 0.03 (3 H, s, SiMe), 0.06 (3 H, s, SiMe), 0.85 (9 H, s, SiCMe3),1.89(1H,d,J11,15e-H),2.13(1H,dt,J12.5,5,5,15a-H),2.40(2H,m,lOa and 16-H), 2.50 (3 H, s, NMe), 2.65 (1 H, dd, J 12.5, 4, 16-H), 2.85 (1 H, t, J 2.5, 14-H), 3.10 (1 H, d, J 18.5, 10~-H), 3.44 (1 H, q, J 3, 9-H), 5.20 (1 H, d, J 6.5, 5-H), 5.43 (1 H, m, 6-H), 5.54 (1 H, d, J 10, 8-H), 5.75 (1 H, d, J 10, 7-H), 6.49 and 6.59 (2 H, ABq, 1 and 2-H), 8.29 (4 H, s, 20, 21, 23 and 24-H); ~c -4.92, 17.96, 20.36, 25.35, 35.43, 40.71, - 42.87, 42.95 (NMe), 46.51, 58.91, 69.85, 87.37, 119.19, 121.23, 123.29, 127.27, 127.49, 130.27, 130.43, 131.01, 135.29, 137.06, 148.42, 150.48, 163.98; m/z 548 (M+, 52%) 491(38), 382(25), 266(21), 137(18), 122(14), 104(40), 92(20), 77(45), 50(79), 41(100).
(Found M+, 548.2331. C30H36N2O6Si requires 548.2342).

F~r~l ~ISPE~1115 2 2 0 1 8 8 6 . . ~ . .
Preparation of 3-t-Butyldimethylsilyloxy-7,8-didehydro4,5a-epoxy-6a-(4-methoxy-benzoyloxy)-17-methyl-morphinan (7 X=OMe in the relevant part of Figure 2) To a solution of 3-t-BDMS-morphine (1) (100 mg, 0.25 mmol) in pyridine (3 cm3), under nitrogen, was added p-anisoyl chloride (0.1 cm3, 128 mg, 0.75 rnrnol) and the S reaction stirred at room temperature for 30 minl-tes. EtOAc was added and the solution washed successively with dilute HCl/water/bicarbonate/water, dried (MgSO4), and evaporated under reduced pressure. The crude product was purified by column chromatography (elution with 5% MeOH in CHCl3) to give the ester (7 X=OMe) (82 mg, 61%) m.p. 173-5C; vmax(CHCl3)/cm~l 1710 (C=O ester); 8H(CDCl3) 0.04 (3 H, s, 10 SiMe),0.06(3H,s,SiMe),0.87(9H,s,SiCMe3),1.88(1H,d,Jll,lSe-H),2.10(1H, dt, J 12.5, S, S, lSa-H), 2.38 (2 H, m, 10a and 16-H), 2.46 (3 H, s, NMe), 2.61 (1 H, dd, J
12.5,4, 16-H),2.80(1 H,t,J2.5, 14-H),3.05(1 H,d,J18.5, 10~-H),3.40(1 H,q,J3, 9-H),3.87(1H,s,O-Me),5.17(1H,d,J6.5,5-H),5.38(1H,m,6-H),5.45(1H,d,J10, 8-H), 5.73 (1 H, d, J 10, 7-H), 6.47 and 6.59 (2 H, ABq, 1 and 2-H), 6.90 (2 H, d, J 9, 21 15 and 23-H), ~.06 (2 H, d, J 9, 20 and 24-H); m/z 533 (M+, 8%) 476(4), 382(3), 324(4), 296(4), 152(5), 135(100), 92(4), 73(11), 51(9), 41(10).
(Found M+, 533.2602. C31H39NOsSi requires 533.2598).

Preparation of 3-t-Butyldimethylsilylo~y-6a-(4-t-butyldimethylsilyloxybenzoyloxy)-20 7,8-didehydro-4,5a-epoxy-17-methyl-morphinan (8 X=OTBDMS in the relevant part of Figure 2) Freshly prepared p-t-BDMS-oxy benzoic acid (500 mg, 1.98 mmol) in DCM
(5 cm3), under nitrogen, was treated with oxalyl chloride (630 mg, 0.43 cm3, 5 mrnol).
Effervescence implied formation of the acid chloride. On completion of the reaction, 25 after 20 minutes, benzene (5 cm3) was added and all solvents removed under reduced pressure. To the acid chloride residue, under nitrogen, was added a solution of 3-t-BDMS-morphine (1) (250 mg, 0.63 mrnol) in pyridine (3 cm3) and the reaction stirred at room temperature overnight. EtOAc was added and the solution washed with dilute HCl/water/bicarbonate/water, dried (Na2S04) and evaporated under reduced ~l~S:jU~. The 30 crude product was purified by column chromatography (elution with 5% MeOH in DCM) to give the ester (8 X=OTBDMS) (276 mg, 70%) m.p. 122-4C; H (CDC13) 0.02 (3 H, AMEND'D SH~Er vo 96/16063 2 2 0 1 8 8 6 PCT/GB95/02712 s, SiMe), 0.04 (3 H, s, SiMe), 0.17 (6 H, s, SiMe2) 0.82 (9 H, s, SiCMe3), 0.94 (9 H, s, SiCMe3), 1.83 (I H, d, J 11, 15e-H), 2.07 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.34 (2 H, m, lOa and 16-H), 2.42 (3 H, s, NMe), 2.58 (1 H, dd, J 12, 4, 16-H), 2.78 (1 H, t, J 2.5, 14-H), 3.00(1 H,d,J 18.5, 10~-H),3.39(1 H,q,J3,9-H),5.13 (1 H,d,J6.5,5-H),5.31 (1 H,m, 6-H), 5.40 (1 H, d, J 10, 8-H), 5.68 (1 H, d, J 10, 7-H), 6.42 and 6.53 (2 H, ABq, 1 and 2-H),6.80(2H,d,J9,21 and23-H),7.94(2H,d,J9,20and24-H).

Preparation of 3-t-Butyldimethylsilyloxy-7,8-~ lro-4,5a-epoxy-17-methyl-6a-succinyloxy-morphinan (9) A mixture of 3-t-BDMS-morphine (1) (300 mg, 0.75 mmol) and succinic anhydride (375 mg, 3.75 mrnol) in pyridine (5 cm3), under nitrogen, was refluxed for 1 hour. The hot reaction ~ e was poured onto ice and the resl-lting white precipitate collected on a filter. The ~ ,ilale was washed with cold water. Cryst~ tion from DCM-petroleum ether gave the ester (9) (225 mg, 60%) m.p. 144-7C; vmax(CHC13)/cm~l 1735 (C=O ester), 1604 (C=O acid); ~H (CDC13) 0.15 (3 H, s, SiMe), 0.20 (3 H, s, SiMe), 0.98 (9 H, s, SiCMe3), 1.86 (1 H, d, J 12, 15e-H), 2.41-2.82 (10 H, m, N-Me, 2xCH2, lOa, 15c~and 16-H),3.00(1 H,d,J 18.5, 10~-H),3.10(2H,m, 14andl6-H),3.79(1 H,q, J 3.5, 9-H), 5.09 (1 H, d, J 6, 5-H), 5.28 (2 H, m, 6 and 8-H), 5.56 (1 H, d, J 10, 7-H), 6.47 and 6.61 (2 H, ABq, 1 and 2-H); ~c ~.78, ~.55, 18.15, 21.19, 25.66, 30.18, 30.95, 33.20, 37.63, 40.92 (NMe), 42.01, 46.16, 58.66, 68.08, 88.18, 119.19, 122.01, 124.45, 127.71, 129.60, 129.94, 137.80, 148.62, 172.70, 172.85; m/z 499 (M', 3%) 456(5), 382(9),324(11), 267(12), 215(29), 105(24), 73(100), 41(94).
(Found M+, 499.2388. C27H37NO6Si requires 499.2390).

Preparation of 3-t-Butyldimethylsilyloxy-6a-(2-carbol-yl,e~zuyloxy)-7,8-didehydro-4,~a-epoxy-17-methyl-mûrphinan (10) A lllixlLllc; of 3-t-BDMS-morphine (1) (250 mg, 0.63 mmol) and phthalic anhydride (500 mg, 3.38 mmol) in pyridine (2 cm3), under nitrogen, was refluxed for 1 hour. The hot reaction lllix~ was poured onto ice and the resultinp white precipitate collected on a filter. The ple~ e was washed with cold water. Cryst~ fion from DCM-petroleum ether gave the ester (10) (237 mg, 69%) m.p. 193-5C (decomp); vmax(CHCl3)/cm~l 220 ~ 886 1714 (C=O ester), 1602 (C=O acid); ~H (CDC13) 0.04 (3H, s, SiMe), 0.06 (3 H, s, SiMe), 0.88 (9 H, s, SiCMe3), 1.97 (1 H, d, J 11, 15e-H), 2.78-2.88 (3 H, m, 10a, 15a and 16-H), 2.91(3H,s,NMe),3.08(1H,d,J18.5,10~-H),3.45(1H,dd,J12,4,16-H),3.59(1H, t,J2.5, 14-H),4.03(1 H,q,J3.5,9-H),5.32(1 H,d,J6.5,5-H),5.40(1 H,d,J 10,8-H), 5.55 (1 H, m, 6-H), 5.80 (1 H, d, J 10, 7-H), 6.54 and 6.66 (2 H, ABq, 1 and 2-H), 7.38(1H,t,J7.5,22-H),7.52(1H,t,J7.5,23-H),7.66(1H,d,J7.5,21-H),7.92(1H, d,J7.5,24-H).

Preparation of 6a-Benzoyloxy-7,8-didehydro-4,5a-epoxy-17-methyl-morphi~an-3-ol (11 X=H in the relevant parts of Figure 2) To a solution of the ester (2) (150 mg, 0.27 mmol) in dry THF (3 cm3), under nitrogen, at 0C, was added TBAF (1 M solution in THF) (1 cm3). The reaction was stirred at 0C for 5 minllt~s and then allowed to warm up to room l~ dlulc, with stirring COIlt;.,~.;..g overnight. The reaction mixture was dissolved in EtOAc and washed with water, dried (Na2S04) and evaporated under reduced ~le;,~ . The crude product was purified by TLC to give the ester (11 X=H), a white powder, (102 mg, 88%).
Cry~t~ fion was from CHC13/MeOH. m.p. 264-8C (decomp); (found C, 73.25, H, 5.85; N, 3.65. C24H23NO4 requires C, 73.2; H, 5.95; N, 3.55%);
vmax(nujol)/cm~l 1713 (C=O ester); ~H(CD3OD/CDC13) 1.88 (I H, d, J 12.5, 15e-H),2.08 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.37 (2 H, m, 10a and 16-H), 2.44 (3 H, s, NMe), 2.61 (1 H,dd,J 12.5,4, 16-H),2.80(1 H,t,J2.5, 14-H),3.04(1 H,d,J 18.5, 10~-H), 3.38 (1 H, q, J 3, 9-H), 5.21 (1 H, d, J 6.5, 5-H), 5.41 (1 H, m, 6-H), 5.49 (1 H, d, J 10, 8-H),5.76 (1 H, d, J 10, 7-H), 6.52 and 6.63 (2 H, ABq, 1 and 2-H), 7.45 (2 H, t, J 8, 21 and 23-H), 7.59 (1 H, t, J 7.5, 22-H), 8.10 (2 H, d, J 7, 20 and 24-H); ~c 20.30, 34.92, 40.23, 42.71 (NMe), 46.58, 58.98, 68.74, 88.07, 116.69, 119.63, 125.34, 128.16, 128.35, 129.46, 129.58, 129.71, 129.71, 129.92, 133.20, 138.27, 144.94, 166.24; m/z 389 (M+, 38%) 268(33), 215(13), 146(12), 122(11), 105(100), 94(6), 77(34).
(Found M+, 389.1623. C24H23NO4 requires 389.1627).

~ 20 1 ~86 ~O 96/16063 PCT/GB9S/02712 Pre~aration of 7,8-Didehydro-4,5a-epoxy-6a-(4-fluorobenzoyloxy)-17-methyl-morphinan-3-ol (12 X=F in the relevant parts of Figure 2) To a solution of the ester (3) (150 mg, 0.29 mmol) in dry TH~ (3 cm3), under nitrogen, at 0C, was added TBAF (1 M solution in THF) (1 cm3). The reaction was stirred S at 0C for S minutes and then allowed to warrn up to room t~llly~ldlul~, with stirring continl-in~ overnight. The reaction mixture was dissolved in EtOAc and washed with water, dried (Na2S04) and evaporated under reduced yn~ e. The crude product was purified by TLC to give the ester (12 X=F), a white powder, (96 mg, 82%). Cr,vst~ tion was from CHC13/MeOH. m.p. 279-83C (decomp); (Found: C, 70.45; H, 5.4; N, 3.3.
C24H22NFO4 requires C, 70.75, H,5.45; N,3.45%); vmax(nujol)/cm~l 1713 (C=O ester);
~H(CD3OD/CDCl3) 1.88 (1 H, d, J 11, 15e-H), 2.06 (1 H, dt, J 12.5, 5, 5, 15a-H),2.37 (2 H, m, 10 and 16-H), 2.45 (3 H, s, NMe), 2.62 (1 H, dd, J 12.5, 4, 16-H), 2.80(1H,t,J2.5,14-H),3.04(1H,d,J18.5,10~-H),3.38(1H,q,J3.5,9-H),5.18(1H, d, J 6.5, 5-H), 5.40 (1 H, m, 6-H), 5.50 (1 H, d, J 10,7-H), 6.51 and 6.62 (2 H, ABq, 1 and 2-H),7.11and7.15(2xlH,d,J8.5,21and23-H),8.09and8.11(2xlH,d,J8.5,20and 24-H); ~C 21.28, 34.77, 40.06, 42.59 (NMe), 46.56, 58.95, 68.66, 87.84, 115.21, 115.56, 116.64, 119.53, 125.15, 128.10, 129.39, 129.86, 132.26, 132.41, 138.36, 145.03, 163.80, 165.32, 167.84; m/z407 (M+, 30%) 284(17), 268(33), 215(14), 146(13), 123(100), 95(31), 84(21). (Found M+, 407.1593. C24H22NFO4 requires 407.1533).
Preparation of 6a-(4-Chlorobenzoylo~y)-7,8-didehydro-4,5a-epoxy-17-methyl-morphinan-3-ol (13 X=CI in the relevant parts of Figure 2) To a solution of the ester (4) (150 mg, 0.28 mmol) in dry THF (3 cm3 ), under nitrogen, at 0C, was added TBAF (1 M solution in THF) (1 cm3). The reaction was stirred 25 at 0C for 5 mim-t~s then allowed to warm up to room t~llly~dlule, with stirring co~ .;g overnight The reaction mixture was dissolved in EtOAc and washed with water, dried (Na2S04) and evaporated under reduced yl~s~ . I he crude product was purified by TLC
to give the ester (13 X-CI) 105 mg, 89%). Cryst~ tion was from CHC13/MeOH.
m.p. 269-72C (decomp); (Found: C, 67.7; H, 5.; N, 3.25. C24H22NClO4 requires C, 68.0; H, 5.25; N, 3.3%); vmax(nujol)/cm~l 1719 (C=O ester); ~H(CD3OD/CDCl3) 1.95 (1 H, d, J 12, 15e-H), 2.29 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.57 (2 H, m, 10a and 16-H), 220~ 886 2.66 (3 H, s, NMe), 3.04 (3 H, m, 10~, 14 and 16-H), 3.75 (1 H, q, J 3, 9-H), 5.22 (1 H, d, J6.5,5-H),5.41(1H,m,6-H),5.51(1H,d,J10,8-H),5.79(1H,d,J10,7-H),6.55and 6.65 (2 H, ABq, 1 and 2-H), 7.39 and 7.42 (2 x 1 H, d, J 8.5, 21 and 23-H), 7.98 and 8.01 (2 x 1 H, d, J 8.5, 20 and 24-H); m/z 423 and 425 (M+,36 and 12%) 300(8), 268(54), 215(21), 141(34), 139(100), 111(32), 94(10), 81(17).
(Found M+, 425.1207 and 423.1237. C24H22NC1O4 requires 425.1227 and 423.1268).

Preparation of 6a-(4-Bromobenzoyloxy)-7,8-didehy(lru-4,5a-epoxy-17-methyl-morphinan-3-ol (14 X=Br in the relevant parts of Figure 2) To a solution of the ester (5) (150 mg, 0.26 mmol) in dry THF (3 cm3), under nitrogen, at 0C, was added TBAF (lM solution in THF) (1 cm3). The reaction was stirred at 0C for 5 mimltes and then allowed to warm up to room tellly~ with stirring col,l;l,l.il-g overnight. The reaction llli~ e was dissolved in EtOAc and washed with water, dried (Na2S04) and evaporated under reduced l,le~ . The crude product waspurified by TLC to give the ester (14 X=Br), a white powder, (97 mg, 80%).
Cryst~ tion was from CHCl3/MeOH. m.p. 279-84C (decomp); (Found: C, 61.25;
H, 4.7; N, 3.05. C24H22NBrO4 requires C, 61.5; H, 4.7; N, 3.0%); vmax(nujol)/cm~l 1718 (C=O ester); ~H(CD3OD/CDCl3) 1.88 (1 H, d, J 12.5, lSe-H), 2.08 (1 H, dt, J 12.5, 5, 5, l5a-H), 2.37 (2 H, m, 10a and 16-H), 2.46 (3 H, s, NMe), 2.62 (1 H, dd, J 12.5, 4, 16-H), 2.81 (1 H, t, J 2.5, 14-H), 3.04 (1 H, d, J 18.5, 10~,-H), 3.40 (1 H, q, J 3, 9-H), 5.18(1H,d,J6.5,5-H),5.40(1H,m,6-H),5.51(lH,d,J10,8-H),5.74(1H,d,J10, 7-H), 6.51 and 6.63 (2 H, ABq, 1 and 2-H), 7.60 (2 H, d, J 8.5, 21 and 23-H), 7.95 (2 H, d, J 8.5, 20 and 24-H); m/z 469 and 467 (M+, 39 and 42%) 268(95), 215(36), 185(92), 183(100), 155(42), 141(23), 94(17), 81(32).
(Found M+, 469.0544 and 467.0583. C24H22NBrO4 requires 469.0713 and 467.0733).

Preparation of 7,8-Didehydro-4,5a-epoxy-17-methyl-6a-(4-nitrol)e.lzo~loxy)-morphinan-3-ol (15 X=NO~ in the relevant parts of Figure 2) To a solution of the ester (6) (300 mg, 0.18 mmol) in dry THF (5 cm3), under 30 nitrogen, at 0C, was added TBAF (1 M solution in THF) (1 cm3). The reaction was stirred at 0C for S mim~t~s and then allowed to warm up to room t~ dlul~, with stirring - 220 1 8~6 ~O 96/16063 PCT/GB9S/02712 co~ overnight. The reaction rnixture was evaporated under reduced ~ . The crude product was purified by TLC to give the ester (15 X=NO2), a yellow powder,(206 mg, 87%). Cryst~ tion was from DMSO/H20. m.p. 260-9C (decomp);
(Found: C, 64.0; H, 5.4; N, S.95. C24H22N206 requires C, 63.7; H, 5.35; N, 6.2%);
S vmax(nujol)/cm~1 1719 (C=O ester); ôH(DMSO-d6) 1.62 (1 H, d, J 11, 15e-H), 2.06 (1 H, dt, J 12.5, 5, S, 15a-H), 2.21 (2 H, m, 10~ and 16-H), 2.31 (3 H, s, NMe), 2.48(1 H,m, 16-H),2.76(1 H,t,J2.5, 14-H),2.89(1 H,d,J 18.5, 10~-H),3.31 (1 H,q, J 3, 9-H), 5.12 (1 H, d, J 6.5,5-H), 5.43 (1 H, m, 6-H), 5.55 (1 H, d, J 10, 8-H), 5.72 (1 H, d, J 10, 7-H), 6.41 and 6.47 (2 H, ABq, 1 and 2-H), 8.22 (2 H, d, J 9, 20 and 24-H), 8.36 (2 H, d, J 9, 21 and 23-H); ~C 19.90, 34.85, 39.94, 42.12, 42.78 (NMe), 46.32, 58.27, 69.38, 86.84, 116.48, 119.16, 123.87, 125.18, 127.64, 130.46, 130.53, 130.98, 135.32, 138.88, 145.14, 150.36, 163.90;m/z434(M+, 14%)268(15),248(16), 136(11), 104(17),91(21), 88(19), 44(100). (Found M+, 434.1479. C24H22N2O6 requires 434.1478).

Preparation of 7,8-Didehydro-4,5a-epoxy-6a-(4-hydro~y~ o~loxy)-17-methyl-morphinan-3-ol (16 X=OH in the relevant parts of Figure 2) To a solution of the ester (8) (500 mg, 0.79 mmol) in dry THF (S cm3), under nitrogen, at 0C, was added TBAF (1 M solution in THF) (2 cm3). The reaction was stirred at 0C for 5 minl-~ec and then allowed to warm up to room temperature, with stirring 20 cot.i;-.;.,g overnight. The reaction mixture was dissolved in EtOAc and washed with water, dried (Na2S04) and evaporated under reduced pressure. The crude product was purified by TLC to give the ester (16 X=OH) (268 mg, 84%). Crystallisation was from CHC13/MeOH. m.p. 178-82C (decomp); (Found: C, 68.1; H, 5.65; N, 3.2.
C24H23NOs requires C, 68.1; H, 5.9; N, 3.3%); vmax(nujol)/cm~l 1715 (C=O ester);~H(CD3OD/CDC13) 1.81 (1 H, d, J 11.5, 15e-H), 2.05 (1 H, dt, J 12.5, 5, 5, 15a-H), 2.34 (2 H, m, 10a and 16-H), 2.43 (3 H, s, NMe), 2.61 (1 H, dd, J 12.5, 4, 16-H), 2.79 (1 H,t,J2.5,14-H),3.02(1H,d,J18.5,10~,-H),3.38(1H,q,J3,9-H),5.15(1H,d,J6, 5-H), 5.34 (1 H, m, 6-H), 5.46 (1 H, d, J 10, 8-H), 5.73 (1 H, d, J 10, 7-H), 6.50 and 6.63 (2 H, ABq, 1 and 2-H), 6.85 (2 H, d, J 9, 21 and 23-H), 7.95 (2 H, d, J 9, 20 and 24-H);
~C 20.38, 34.68, 39.94, 42.48 (NMe), 42.62, 46.56, 58.94, 68.27, 88.15, 115.30, 116.78, 119.58, 120.47, 125.27, 128.48, 129.19, 129.97, 132.04, 138.28, 145.02, 162.06, 166.27;

220 ~ 88~

mlz 405 (Mt, 11%) 285(14), 210(14), 155(15), 138(23), 121 (84), 94(100), 65(42), 51 (28), 44(49). (Found M+, 405.1569. C24H23NOs requires 405.1576).

Preparation of 7,8-didehydro-4,5a-epoxy-17-methyl-6a-succinyloxy-5 morphinan-3-ol (17) To a solution ofthe ester (9) (150 mg, 0.3 mmol) in THF (2 cm3), under nitrogen,at 0C, was added TBAF (1 M solution in THF) (1 cm3). The reaction was stirred at 0C
for S .,.;..~ s and then allowed to warm up to room le.l.~ dLulc:, with stirring C(JIll;..l.;l-g overnight. The reaction mixture was quenched with water. The resnltin~ cci~iL~e was collected on a filter giving the acid/ester (17) (62 mg, 54%). Crystallisation was from CHCl3/MeOH. m.p. 275-9C (decomp); vmax(nujol)/cm~l 3382 (OH), 1736 (C=O ester),1605 (C=O acid); ~H(CD3OD/CDCl3) 1.96 (1 H~ d, J 12, 15e-H), 2.43-2.86 (10 H, m,N-Me, 2xCH2, 10a, 15a, and 16-H), 3.04 (1 H, d, J 18.5, 10~-H), 3.15 (2 H, m, 14 and 16-H), 3.83 (1 H, q, J 3.5, 9-H), 5.11 (1 H, d, J 6, S-H), 5.30 (2 H, m, 6 and 8-H), 5.58 (1 H, d, J 10, 7-H), 6.57 and 6.61 (2 H, ABq, l and 2-H).

Preparation of 6a-(2-Carboxybenzoyloxy)-7,8-didehydro-4,5a-epoxy-17-methyl-morphinan-3-ol (18) To a solution of the ester (10) (300 mg, 0.18 mmol) in pyridine (5 cm3), under 20 nitrogen, at 0C, was added HF-pyridine (1 cm3). The reaction was stirred at 0C for 5 minlltes and then allowed to warm up to room te~ dLule, with stirring co.,~ .;..g overnight. The reaction lllixLule was quenched with water. The reslllting precipilale was collected on a filter giving the acid/ester (18) (135 mg, 57%). Cryst~ tion was from CHC13/MeOH. m.p. 225-8C (decomp); (Found: C, 65.5; H, 5.35; N, 2.85. C2sH23NO6 requires C, 65.2; H, 5.65; N, 3.05%); vmax(nujol)/cm~l 3398 (OH), 1716 (C=O ester), 1601 (C=O acid); ~H(CD3OD/CDCl3) 2.03 (1 H, d, J 10, 15e-H), 2.90 (3 H, m, 10a, 15a and 16-H), 3.01 (3 H, s, NMe), 3.21 (1 H, d, J 18.5, 10~-H), 3.48 (I H, d, J 8, 16-H), 3.86(1 H,t,J2.5, 14-H),4.12(1 H,q,J3,9-H),5.53 (2H,m,6and8-H),5.66(1 H,d, J 6.5, 5-H), 5.91 (I H, d, J 10, 7-H), 6.59 and 6.63 (2 H, ABq, 1 and 2-H), 7.40 (1 H, m, 22-H), 7.56 (2 H, m, 21 and 23-H), 7.92 (I H, d, J 7.5, 23-H); m/z (M+, 433) 285(100), 268(11), 215(21), 162(29), 124(17), 104(96), 76(79), 42(31).

~JO 96116063 ~ PCT/GB95/02712 IlV V7VO EXPF,RIMF'.NTS
EXAMPLE 3: OPIOII)RFCEPTORPROFILE
Solutions Tris buffer was ~ d as 50mM in distilled water and the pH adjusted to 7.4 with S HCl(4N). Tris-NaCI buffer contained lOOmM NaCl.
Krebs buffer solution for the myenteric plexus longitudinal muscle (MPLM) comprised the following:-NaCl (6.92g/1), KCl (0.35g/1), KH2P04 (0.16g/1), CaC12.2H20 (0.375g/1 forMPLM and 0.188g/1 for RVD), NaHC03 (2.1g/1), MgS04.7H20 (0.29g/1) and glucose (2g/1). The buffer was gassed with 95% 2~ 5% C2 Krebs solution for the mouse vas deferens (MVD) plc~lion was as above, but with the omission of MgSO4.7H2O (Ward et al., 1986, J. Ph~rrn~ol. Exp. Ther., ;~, 625-634). Krebs/HEPES buffer was made up as Krebs buffer (above) with HEPES at a concentration of 25mM adjusted to pH 7.4 with 0.88M ammonia solution.
Methods T,~z-nd binllin~ assays Brain homo~enates Brains were removed from male CSI mice (discarding the cerebellum) and homogenised in Tris buffer (50mM, pH 7.4) at 10% tissue w/v. The homogenate was centrifuged at 25,500g for 20 mins. The supern~t~nt was discarded and the pelletresuspended in buffer. The suspension was inc~lb~tPcl at 37C for 30 mins, then recentrifuged. The pellet obtained was .~;,u~GIlded in buffer to obtain a 1 :60 tissue w/v ratio. This dilution co..~ ollds to a protein concentration of app~ illlately lmg/ml as ~iet~rrnined by Lowry's method (Lowry etal., 1951, J. Biol. Chem., 193, 265-275).
For saturation binding assays tubes were set up co~ i"g 20111 of tritiated ligand and 960~1 of brain homogenate in a total volume of lml. 20111 of naloxone (lO,uM) was added to each tube to deterrnine the non-specific binding. For competition assays tubes contained labelled ligand (usually l.OnM final concentration) plus increasing concentrations of competing cold ligand, or 20!11 of water or 20111 of naloxone (lO,uM), which represented the total bound ligand and non-specifically bound ligand values respectively. Assay tubes were inc~lb~te(l at 25OC for 40 mins, unless stated otherwise. At 22() ~ 8~6 the end of the incubation period the tube contents were filtered through glass filter papers (Whatman GFB) which were preso~ked in either Tris buffer pH 7.4 or Tris-buffer pH 7.4 co~ g polyethyleneimine (0.1 %) to reduce non-specific binding to filters. The tubes were washed three times with 3ml of ice cold Tris buffer and the washings were also 5 filtered. The filters were placed in scintillation vials, ecoscint scintill~nt fluid added, and the filters soaked for 8 hours. The radioactivity rem~ining on the filters was counted in a Minaxi Tricarb 4000 Series Liquid Scintill~tion Counter at an efficiency of 58%.Binding parameters KD and BmaX were obtained using the LIGAND programrne, following Scatchard analysis using the EBDA progr~mme (McPherson,1985, J. P~ ",~ol.
Meth., 14, 213-228). ICso values for competing ligands were detPrminPd using a logistic curve fitting programme developed by Barlow (1991, Ash Lea Cottage, Ravenstonedale, Kirkby Stephen, Cumbria. Foundations of pharmacology-co~ ul~l curve fitting programme, publisher, Barton 1991).
I~olat~d tissuç st~ldies Tissue prcparation a) Guinea-pi~ myenteric plexus-lon~itudinal muscle (MPLM) b~o~s ,,.y Male Dunkin-Hartley guinea-pigs (400-500g) were killed by cervical dislocation.
The ileum was removed and imm~ t~ly placed in~r~ted Krebs solution at room te~ c;ldLulc (Ward et al., 1986, J. Ph~rm~sol. Exp. Ther., ~, 625-634). After flushing out the collL~ll~, strips of myenteric plexus longit~ in~l muscle (MPLM) were removed and mounted, under a tension of 1 g, in 3ml organ baths previously coated with silicon to reduce adsorption of peptides onto the glass surface. Tissues were bathed in Krebs solution at 37C, aerated with 5% CO2 in 95% 2 After allowing a recovery period of 1 h, each tissue was stimul~t~d through platinurn ring electrodes using square wave pulses at supramaximal voltage at a frequency of 0.16Hz and a pulse width of 400~Ls.
b) ~Iouse vas deferPn~ (MVD) preparation Male CSI mice (930-50g), were killed by cervical dislocation. The vasa deferentia were removed immediately, and mounted under a tension of 0.5g in 1.8ml organ baths, previously coated with silicon to reduce adsorption losses of peptides. Tissues were bathed in Krebs without MgSO4 at 37C, aerated with 5% C2 in 95% 2 After allowing a recovery period of 1 h, each vas deferens was sfim~ te~l through pl~tinllm ring electrodes ~ 2201 81~
O 96tl6063 PCT/GB95102712 using a train of 3 square wave pulses of lms duration and 250ms delay at supr~m~im~l voltage at a frequency of 0.1 Hz.
F~perimental For all in vitro l"~p~lions the same procedure was performed as follows:-5 a) ~gonist potencies Agonists were added to the organ baths in a cllmnl~tive way such that when the response to any one dose reached a m~ximllm the next dose was ~tlmini~t~red, until approximately 80% inhibition of twitch height was ~tt~in~ after about four cllmlll~tive doses. The tissues were washed by overflow with Krebs solution until the original twitch 10 height was restored. The potency of agonists was ~se~ed by measurement of ICso's, the concentration of agonist c~ in~ 50% inhibition of the electrically evoked twitch.
b) Ant~q~onist affinities Antagonists were preincubated with the ~l~lu~liate tissue for l 5 mins, prior to the addition of an agonist. Dose-response curves for agonists were obtained before the addition 15 of an antagonist and then repeated in the presence of varying concentrations of the antagonist (normally 10, 30, 100nM)> Dose-ratios were calculated at 50% inhibition and Schild plots constructed. Antagonists were removed from the tissue by continuous washing until the response to the added agonist was fully recovered. In some t;~ i,llents antagonist Ke values were calculated using a single-dose method. The antagonist 20 equilibrium dissociation constant (Ke) is a measure of affinity and was determined for a partial agonist in the rat vas deferens by pre-inr~lb~ting the test compound for 15 mins and observing the effect on the dose-response curve for the full ~ agonist DAMGO. Antagonist equilibrium dissociation constants (Ke) were obtained by analysing the results according to Kosterlitz and Watt (1968, Br. J. Pharmacol. Chemother., 33, 266-276).
25 Results Opioid Receptor Profile - Morphine and morphine-6-~lucuronide - The purpose of this experiment was to test analogues of morphine-6-glucuronide for their selectivity for different opioid binding sites. r ig~nr1c which have relative selectivity for different opioid binding sites are well known. The ~ffiniti~s of some 30 illustrative compounds, DAMGO ([D-Ala2, MePhe4,Gly-ol5]encephalin, DPDPE
([D- Pen2,D-Pen5]çn~eph~1in) and U69593 which have high affnities and are selective for the opioid ~ -, and lC- binding sites respectively are shown in Table I below:

Table 1: ~fflniti~ of opiates and specific ligands at mu, delta and kappal,i..(liu~ sites in mouse brain homogenates.

Ki (nM) Compound ~ L ,~ ~c morphine 6.22 + 0.86 218.0 ~ 41.2 84.7 + 4.01 morphine-6-glucuronide 7.90+ 1.48 75.1 ~ 15.6 850 + 118 morphine-3-glucuronide > 10,000 > 10,000 > 10,000 DAMGO 2.45 ~ 0.40 423.0 ~ 7.9 1267 ~ 265 DPDPE > 10,000 4.76 + 1.44 600 ~ 124 U69593 > 10,000 > 10,000 2.51 + 1.22 At the 3 opioid binding sites, morphine and M6G demonstrate the highest affinity for, and 20 are approximately equipotent at, the ~-site (Table 1). The profile of morphine and M6G
affinities differ, however, at the ~- and lc- sites, M6G being approximately 3-fold more potent at ~-sites and 10-fold less potent at lC- sites than morphine.
The actions of morphine and M6G on 2 isolated tissue plcpdldlions, namely the guinea-pig myenteric plexus-longitudinal muscle (MPLM) and the mouse vas deferens 25 (MVD) are shown in Table 2. M6G is slightly more potent than morphine (approximately 2-fold) in both ~ dLions. Also on both isolated tissues, the concentration of naloxone required to antagonise morphine and M6G to the same degree Ke) is equivalent and similar to that required to antagonise the selective !l-receptor ligand DAMGO (approximate Ke) naloxone = 3nM in each case). Thus the agonists actions of morphine and M6G on the 30 MPLM and MVD are due to actions at the ~ ecel"ol in both isolated tissue ~lc~dldlions.
Relatively higher concentrations of naloxone are required to antagonise ~-mediated effects (DPDPE on the MVD, Ke naloxone = 20.4nM) and lc-mediated effects (U69593 on the MPLM. Ke naloxone = 9.0nM).

~, . 220 1 ~86 Table 2: Against potencies and antagonism by naloxone in the mouse vas def~
(MVD) and 7~ pig ~ e. ic IJ~ , lorlgitudinal muscle (MPLM) preparations.

MPLM MVD

CompoundK50/nM Ke(Nx)/nM K50/nM Ke(Nx)/nM

morphine130.0 ~ 7.23.45 + 0.59173.4 + 62.8 3.60 + 0.80 M-6-G 58.0 + 4.3 3.00 + 0.80104.2 + 17.1 2.61 + 0.90 DAMGO11.8 + 1.2 1.60~ 0.06 24.7+ 3.0 1.90+ 0.60 DPDPE NT NT 2.80 ~ 0.63 20.4 + 2.6 U695932.20 + 0.419.00 ~ 2.11 NT NT

NT = not tested 20 Morphil~c-6 t II.curonide analo~ues Opioid Bin-li~ Site Affinities Analogues were tested and selected to at least retain and preferably exaggerate the relative binding profiles of M6G co~ ~cd to morphine, i.e. equivalent, high affinity at ~1-sites, and decreased afflnity at lc-sites. Initially, 6-substituted codeine derivatives (i.e. with 25 a 3-OMe function) were investig~t~l as target compounds. Such derivatives, e.g. 3-OMe, 6-~hth~l~te (BTG 2379) were shown to have low affinity for !l-binding sites (Ki=4SOOnM, Table 3). 3-silylmorphine (BTG 2381), however, itself retained a high affinity for ~l-sites (Ki=2.5nM) and 3-silyl compounds were used as plCIJdld~ e intt?rrne~ tt?~ for 6-substituted analogues. The addition of an aromatic ring at the 6-position, particularly phth~ te (BTG
2382) and to a lesser extent benzoate (BTG 2383), further bçnefici~lly modified the binding profile. Table 3 below shows that BTG 2382 and BTG 2383 retained affinity at ~l-binding sites (Ki = 17.5 and 31 OnM respectively), whilst losing lc-binding activity S (Ki = > 10,000nM) and ref~ining ~-activity, in the case of BTG 2382 the affinity at the ~-site being in fact t?nh~nl~ecl m~rk~rlly (Ki = 4.1nM, Table 3). Analogues with 6-phth~l~te and 6-benzoate substitutions were investig~teA~ therefore, ,etl" "i"g to desilylated, morphine based structures (i.e. 3-OH). As with the ~.c,L~ed series and shown in Table 4, the 6-phth~l~t'? ester of morphine (BTG 2403) retained good affinity at the ~-binding site (Ki = 27.8nM), slightly higher affinity at the ~-binding site (14.2nM) and low affinity at the lc-binding site (Ki = 2774nM). A series of para substituted 6-benzoate analogues (Table 4) demonstrated that the 6-(p-nitrobenzoate) ester (BTG 2404) showed a related profile with again good affinity at the ,u-binding site (Ki = 30.1nM), slightly lower affinity at the ~-binding site (Ki = 68.5nM), but no demonstrable affinity at the lc-binding site, at least up to 10,000nM. The 6-(p-hydroxybenzoate) ester (BTG 2408) also displayed a related profile with high affinity at the ~l-site (Ki~ = 1.7nM, Ki~ = 22.2nM, Kilc = 157nM, Table 4). Morphine-6-phth~l~te (BTG 2403), morphine-6-(p-nitrobenzoate) (BTG 2404) and morphine-6-(p-hydroxyb~n70~t~) (BTG 2408), therefore, all extend the differences in binding profile seen in M6G co~ d to morphine; all 5 compounds having ll-affinity in the 1-30nM range, with ~-affinities, ranging from morphine of 218nM to BTG 2403 of 14.2nM, and lc-affinity, ranging from morphine of 84.7nM to BTG 2404 of >10,000nM.

- 2201 &~6 ~/0 96/16063 PCT/GB95102712 Table 3: Affinity of 3,6-sul"lil~l_d morphine d~ liv_s at mu, delta and kappa binding sites in mouse brain homogenates.

~r~

R1 0~ ~oR2 Ki (nM) Compound Rl R2 ~1 ~ K
BTG
morphine H H 6.22~0.86 218.0 1 41 84.7 1 4.0 codeine Me H 2700+ 3.02 NT NT
2379 Me phth~l~te 4500~ 513 NT NT
2381 silyl H 2.50 ~ 0 41 175 ~ 6 135 ~ 14 2382 silyl phth~l~te 17.5 ~ 2.8 4.1 1 0.3 >10,000 2383 silyl benzoate310 + 22 485 ~ 25 >lO,000 Table 4: Affinity of 6-suL,slil~.led morphine derivatives at mu, delta and kappabinding sites in mouse brain homogenates.

Ho~o /~R4 Ki (nM) Compound R3 R4 ~1 ~ lC
BTG
morphine 6.22 ~ 0.86218.0 ~ 41.2 84.7 + 4.0 M-6-G 7.90+ 1.48 75.1 + 15.6 850+ 118 2403 COOH H 27.8 i 3.8 14.2 + 2.9 2774 + 205 2404 H NO230.1 + 1.4 68 + 4.6 >10,000 2405 H F 16.6 + 3.2 83.3 + 6.8 193.2 +14.1 2406 H Cl 17.7+ 2.8 84.9 + 8.4 149.9 +12.2 2407 H Br 28.4+ 5.2 205.0 +10.2 832.9 +24.1 2408 H OH1.73+ 0.26 22.2 + 3.4 157.0 +12.6 Opioid activity on isolated tissues The above series of 6-substituted morphine derivatives was tested for activity on 35 the isolated tissue ~lc~.~d~ions described previously. The results are shown in Table 5.

220~ ~86 o 96/16063 ~ Pcr/Gss5/027l2 Table 5: Pol~ s of 6-s~ le~l morphine d~ s in the guinea-pig MPLM and mouse vas deferens (MVD) preparations.

ICso nM

Compound 6- MPLM MVI) BTG s~hstitntion morphine H 130.0 - 7.2 173.4 i 62.8 M-6-G glucuronide58.0 + 4.3 104.2+ 17.1 2403 phth~l~te350 _ 25 24.3 ~ 3.5 2404 p-NO2-bz132 + 12 1166+ 467 2405 p-F-bz1010 + 102 1325 + 262 2406 p-Cl-bz1506 ~t 161 1162 + 151 2407 p-Br-bz1800 + 183 1281 + 186 2408 p-OH-bz9004 ~ 106 230 ~ 18 As ~ cl-c~ecl previously, although M6G has a slightly higher affinity in brain homogenate plcy~dlions for b-binding sites co~ d to morphine (approximately 3-fold increase), on a relevant isolated tissue pl~paldlion, the mouse vas deferens (MVD), the potency difference is small (approximately 1.7-fold). Studies with the opioid antagonist naloxone on the MVD show that M6G, like morphine~ is still acting via ~1- and not a-receptors in this tissue.
It was of interest, therefore, to investigate whether representative examples of the 6-substituted analogues with high a-binding affinity in mouse brain homogenates were exerting their agonist effects on the MVD through tl- or ~-receptors in this isolated tissue.
3 compounds were studied, 3-silylmorphine-6-phth~l~te (BTG 2382, Ki ~ binding = 4.1nM), morphine-6-(p-nitrobenzoate) (BTG 2404, Ki a binding = 68.5nM) and morphine-6-(p-hydroxybenzoate (BTG 2408, Ki a binding 22.2nM). The respective ICsos of these compounds on the MVD were 41nM, 1166nM and 230nM. As shown in Table 6, the Ke's for antagonism by naloxone of BTG 2382, BTG 2404 and BTG 2408 were similar and in the range 14.9 - 20.2 nM. The concentrations of naloxone required for WO 96/16063 i 2 0 1 8 8 6 PCT/GB95/02712 '~
antagonism of the analogues are considerably higher (approximately 6-7 times) and in marked contrast to that required for equivalent antagonism by naloxone of morphine and M6G (Ke naloxone = 3.6nM and 2.6nM respectively).
Thus, whereas in the MVD isolated tissue l)rel,~dLion morphine and M6G act via S ll-receptors, the 6-substituted morphine analogues tested acted on this tissue via ~-receptors.
As may be expected, on the guinea-pig ileum myenteric plexus-longih~-lin~l muscle (MPLM) plc~dLion which lacks functional ~-lec~lulj, naloxone antagonism of all ~compounds showed similar Ke's (range 3.0 - 4.1 nM) indicating their action on this tissue 10 is via ~L-lece~)~ol~.

Table 6: Antagonism by naloxone of morphine and de. ;valives on the MPLM and MVD isolated tissue preparations.

Compound Sul,slil~lion Ke naloxonenM

morphine OH H 3.5 + 0.611 3.6 + 0.8 M-6-G OH glucuronide 3.0+0.811 2.6~0 9 !
2382 silyl phth~l~te 4.1 + 1.4~120.2 ~ 3.0 ,b 2404 OH p-N02-bz 3.5 + 0.3~114.9l 1.5 2408 OH p-OH-bz 3.2 + 0.41117.8 l 1.9 F~ OISPEC~AM9611~5 2 2 0 1 8 8 6 ~ . .
... ...
IN VIVO EXPERIMENTS:
EXAl~IP1E 4: GFl~ERAL METHOD FOR ASSESSING THE ANTINOCI(,`~
~CTIVITY OF COMPOUNDS OF THE INVENTION
The antinociceptive effects of morphine and morphine-6-glucuronide in ~nim~l~
(and analgesia in man) are well known. In the present studies, therefore, only one confirm~tory study was carried out in the mouse tail-flick test which showed, bysubcutaneous ~11mini~tration, morphine and morphine-6-glucuronide to be equipotent, EDso = 2.2 gl/kg and l.9 mg/kg respectively, see Table 12 below.
Male CSI mice (25.30 g) (University of Noltin~h~m Medical School) were used in these experiments. Animals were housed in groups of twelve in a room with a L~ Lu~c;
controlled at 20C on a 12 hour light-dark cycle and with free access to food and water.
Compounds of the current invention morphine sulphate and related compounds or vehicle controls (saline with 0.25% carboxy- methylcellulose) were injected subcutaneously. Six control mice (injected with vehicle) and six test mice were used for lS each study. Where antagonists were used thése were injected subcutaneously 15 minlltes prior to the agonists.
Antinociceptive activity was determined by the mouse tail-immer~ion test as follows:
Prior to injection and at the stated times past injection the tail was immersed in warm water at 50C. The time for withdrawal of the tail was recorded. Antinociception was de~rmin~cl by an increase in the time-latency to withdrawal. The cut-off tirne for non-responding ~nim~l~ was l0 seconds. The time to reach maximal analgesie was dedll~etl and ED50 values obtained for each drug as a measure of potency. The same points were subtracted from the test points and the dose required to give 50% of the m~xim~l tail-flick latency (EDso) was de~ ce~l The results are shown in the following Tables.

~,~,AE~E~ S~Er 220 1 ~6 Table 7: Antinc~ ~ ~ti~e acli~ of morphine-6-p-nitroben7O~t~ and morphine-6-phth~ t~ in the mouse warm-water tail flick test Compound Tail-flick 1~ _~(s) Morphine-6-~-nifrobezort~ vehicle control drug 10I mg/kg 2.2~0.4 2.6~0.4 3 mgAkg 1.9 + 0.2 2.7 + 0.1 10 mg/kg 1.3 + 0.2 2.1 + 0.1 30 mg/kg 1.7 + 0.1 5.0 + 0.1*
Morphine-6-phrho/~f~
151 mg/kg 1.3 ~0.1 2.3 +0.3 3 mg/kg 2.7 + 0.2 5.5 + 0.3*
lOmg/kg 1.7 + 0.2 6.7 ~ 0.3*
30 mg/kg 1.4 + 0.2 8.2 + 0.9*

Drugs were ~1ministered s.c. in saline co~ Q.25% carboxylmethylcellulose and tail-flick latencies were measured at 50C, 60 .,.;.. ,.l~s later. There were six ~nim~l~ in each group *P<0.05 (Wilcoxon signed rank test).

~o 96/16063 2 2 0 1 8 8 6 PCT/GB95/02712 Table 8: Time course of the antino~;c~plive activity of morphine-6-p-nitroben~o~t~
(10 mg/kg s.c.) and morphine-6-phthalate (10 mg/kg s.c.) in the mouse war ..
tail-flick test Tail-flick latency (s) Time (mins) vehicle confrolmorphine-6-~-nitrobf"~z~ "t~morphine_6_phthnl,7t~
-15 2.5 + 0.2 1.9 + 0.2 2.3 + 0.2 2.8+0.3 2.8~0.5 3.0+0.4 3.2+0.4 5.3+0.5* 4.6+0.3*
2.9 ~ 0.3 7.3 ~ 1.0* 5.9 ~ 0.5*
3.0 + 0.3 8.9 + 0.9* 6.2 + 0.6*
120 2.8+0.2 8.4~0.8* 7.0~0.5*
240 2.6 ~ 0.2 4.1 ~: 0.9* 3.4 + 0.3*
360 2.3 + 0.2 2.2 + 0.3 2.1 + 0.2 Drugs were ~-lmini~tered s.c. in saline co~ g 0.25% carboxymethylcellulose and tail-flick latencies cl~L~ . .,.il-~d at 50C at the stated times. There were 6 mice in each group.
*P<0.05 (Wilcoxon signed rank test).

Discussion Tables 7 and 8 show dose-related antinociceptive activities of the morphine-6-ph~h~l~te (BTG 2403) and morphine-6-~-nitrobenzoate (BTG 2404) on subcutaneous ~rimini~tration in the mouse tail-flick assay. BTG 2403 was slightly more potent than BTG 2404, ICsos being 2.6 mg/kg and 16.2 mg/kg respectively.
Data from similar experiments with morphine (5 mg/kg and morphine-6-glucuronide were compared. The results are shown in Tables 9 and 10 below.

~ 2 ~ 6 Table 9: Time Course Experiment of the antinoc;c~ e acli~ily of morphine, 5mg/kg s.c. and morphin~6-~lncuronide (M6G) 5mg/kg s.c. in the mouse warm water flick tail test Time(mins) Vehicle Morphine- Ve~icle M6G
Control treated Control treated -15 2.2+0.3 2.1 +0.2 2.6+0.3 1.8+0.3 2.6 i 0.4 8.5 + 0.6 * 3.6 + O.S 7.6 + 1.2 *
3.8~0.3 9.8+0.2* 2.9~0.4 10*
2.9 + 0.2 10 * 3.4 + 0.3 10 *
2.7+0.2 9.8+0.2* 2.8+0.3 10*
lS 120 3.0 + 0.2 7.9 + 0.5 * 3.0 + 0.2 10 *
240 2.7+0.2 4.9~0.6* 3.0+0.2 10*
360 2.8~0.2 2.7+0.2 2.5~0.2 10*
540 NT NT 2.5 + 0.2 7.1 + 0.9 *
720 NT NT 1.8 + 0.2 3.2+ 0.5 *
1440 NT NT 1.8 + 0.1 2.0 + 0.4 NT = not tested Drug was ~-lmini~tered s.c. (sub-~;ul~leo~sly) in saline and tail flick latencies (SOo water) ~l~L~ . . .;, .~-1 at the stated times. A cut-off time of 10 seconds was used. There were 25 six mice in each group * P < 0.05 (Wilcoxon signed rank test).

220 1 8~6 ~O 96/16063 PCT/GB95/02712 Table 10: Dose effect responses for tlhe antino~;c~ e effect of morphine and morphil.c-6 ~ I~,curonide (M6G) in the mouse warm water tail-flick test Tail flick latency (seconds) SCompound Morphine M6G
mglkg 0 2.4+0.3 2.3+0.1 0.3 3.5 ~ ~.4 * 3.4 ~ 0.3 *
1.0 3.9~0.4* 3.8~t0.5 *
3.0 7.0 + 1.0 * 9.2 + 0.6 *
5.0 10* 10*
10.0 10 * 10 *

Drug wæ a(lmini~tered in saline, subcutaneously, using 6 mice for each con~ntr~tion. Tail flick latencies were determinecl 60 minl-tes after injection using SOoC
water. A cut-offtime of 10 seconds was used.
* Represents P < O.OS (Wilcoxon signed rank test) Peak antinociceptive activity with BTG 2403 and BTG 2404 (120 minlltes and 90 ~ ) was delayed co~ ,~ed to that of morphine (60 minlltes) and activity by all 3 compounds had returned to control levels 360 minllt~s after subcutaneous ~rlmini~tration.
With an ~xtton~ion of the profile of the 6-substituted analogues in binding and in vitro studies demon~L,d~ g increased affinity and actions merli~ted by the ~-receptor, one compound, the 6-phth~l~te ester of morphine (BTG 2403), was tested for ~-mP~ tPd effects in an antinociceptive test, the mouse tail-flick. Results are shown in Table 11.
Morphine (Smg/kg) and BTG 2403 (30mg/kg), ~1mini~tered subcutaneously, demon~tr~t~cl approximately equivalent antinociceptive effects. The selective ~-receptor antagonist n~l~rin~ le (lmg/kg sc) completely antagonised the effects of BTG 2403, but had no effect on those intl~lce~l by morphine. BTG 2403 would appear to exert antinociceptive effects via ~-opioid receptors.

Wo 96/16063 2 2 ~ b PCT/GB95/02712 Table 11: Ef~ect of naltrindole (1 mg/kg) on the antino~;c~ e a~ ily of morphine(5 mg/kg) and morphine-6-phthalate (30 mg/kg) in the mouse warr .. at~. tail-flick test Tr~ .,t Tail-flick latency(s) pre-test 2.0 + 0.3 vehicle 2.3 ~ 0.2 naltrindole 2.2 ~ 0.2 morphine 10.0 (cut-off)*
morphine + n~ltnntlole 10.0 (cut-off~*
morphine-6-phth~ te 9.8 ~ 0.2*
mol~hillc-6-phth~l~te + n~ltrin~lole 2.5 ~ 0.3 Drugs were ~lmini~t~red subcutaneously in saline co~ g 0.25%
cdll,o~sylllethylcellulose and tail-flick latencies were determinPd at 50C 90 minlltes (morphine) or 120 min-ltPs (morphine-6-phth~l~te) later. Naltrindole was ~-lmini~tered 15 mimlteS prior to the agonists. *P<0.05 (Wilcoxon signed rank test).

EXAMPLE 5: Al~ITINOCI(~ F FFFECTS OF MORPHINE
AND DERIVATIVES
OP~AT, AN~l-GESIC STUDY:- PAW LICKING T~!;;T IN MICE
Male, LACA mice (Tucks), weighing between 30-40g, were dosed orally with the vehicle or compound, 1 h prior to the sub-plantar injection of 10 ~11 of 5% formalin. The duration of paw licking was measured 0-5 min and 15-30 min after formalin ~ h li~i, dlion.
The vehicle was 0.25% carboxymethylcellulose in 0.9% saline and solutions were sonicated and shaken prior to ~-lmini~tration; this was especially necess~ for the high concentrations of the two test compounds (morphine-6-phth~l~t~ and morphine-6-l2-nitrob~n70~te).

~o 96/16063 PcT/Gss5/027l2 All experiment.s were l.~,ro-,l,ed between 1400-1700h and in any one experiment at least one control animal and three of the compounds were studied.
Animals were removed from the animal house at 1300h and the temperature of the behavioural room was noted (it did not exceed 25 C although several of the t;x~.;, . .ent~
S were ~lr~l.l.ed when the outside te...~;.dlu,e was 30-350C).
The duration of licking in the treated groups was ~ ~cd with that of the controls using one-way ANOVA followed by the Dunnett Multiple Comparison Test. A non-pararnetric test (Kruskal-Wallis, followed by Dunn's Multiple Comparison Test) was also used as there was some concern about the norrnal distribution of the values. Calculations 10 were p~.rc,~ cd through the INSTAT programme.
The results are shown in Table 12 below Table 12: Antinociceptive effects of morphine and d~ tlives Antinociceptive e~ect Compound 6- tail-Jlick paw-lick BTG sl~hstitution EDso mg/kg lowest dose *
sc po morphine OH 2.2 + 0.3 10.0 M6G glucuronide 1.9 ~ 0.3 No effectat 80 2403 phth~l~tt~ 2.6 + 0.4 40.0 2404 p-NO2-bz 16.2+ 2.6 40.0 * lowest dose producing a statistically significant (p < 0.05) antinociceptive effect.
Morphine in~ ce~l, dose related arltinociceptive effects were observed at doses of 30 10 mg/kg and higher. In comparison, morphine-6-glucuronide failed to induce statistically significant antinociceptive effects at any dose tested (10-80 mg/kg po). BTG 2403 and BTG 2404 (both at 40 mg/kg) incl~l-e~l antinociceptive effects on oral ~flmini~tr~tion although dose related effects with a highest dose were demon~tr~tecl only with the latter compound.

WO 96/16063 ~ 2 0 1 8 8 6 PCT/GB95/02712 Boththe 6~ LiL~ aromatic analogues, therefore showed st~ti~ti~lly significant oral antinociceptive effects, the compound being slightly less potent than morphine, but more potent than morphine-6-glucuronide, which failed to demonstrate antinociceptive effects, even at the highest dose tested.

Claims

1. A compound of Formula I

wherein R1 = H (morphine analogue), CH3 (codeine analogue) R2 = H, alkyl group of 1 to 4 carbon atoms, allyl, cyclopropylmethyl R3 = a group -O-CH2-R4 (ether) -O-COCH=CHR4 (cinnamate) R4 =

wherein X1,X2,X3,X4 and X5 which may be the same or different are separately selected from H, alkyl of 1 to 4 carbon atoms, NH2, NO2 alkoxy group of 1 to 4 carbon atoms, hydroxy, halogen, N-alkyl, group of 1 to 4 carbon atoms, morpholine, or a group COR5 wherein R5 is H, OH, O-alkyl where alkyl is from 1 to 4 carbon atoms, or one of X1 and X2, X2 and X3, X3 and X4 or X4 and X5 together with an alkylene group optionallyinterrupted by O, S or N of up to 5 atoms in length complete a ring and a pharmaceutically acceptable salt thereof for use in therapy.

2. A compound according to Claim 1, wherein R2 is H or alkyl group of 1-4 carbonatoms or pharmaceutically acceptable salts thereof.
3. A compound according to Claim 2, wherein the alkyl group is methyl or pharmaceutically acceptable salts thereof.
4. A compound according to Claim 1, 2 or 3 wherein R3 =
or pharmaceutically acceptable salts thereof.
5. A compound according to any preceding claim wherein R4 is wherein X1,X2,X3,X4 and X5 which may be the same or different are separately selected from H, NH2, NO2, OH, halogen or COR5 wherein R5 is OH or pharmaceutically acceptable salts thereof.
6. A compound according to Claim 5, wherein at least 3 of X1,X2,X3,X4 and X5 are H or pharmaceutically acceptable salts thereof.
7. A compound according to Claim 5 or 6, wherein when there is only one substituent, the X substituent is in the para position or when there is more than one substituent, one is in the para position or pharmaceutically acceptable salts thereof.
8. A compound according to Claim 1 which is morphine or codeine-6-nitrobenzoate or pharmaceutically acceptable salts thereof.
9. A compound according to Claim 1 which is morphine or codeine-6-phthalate or pharmaceutically acceptable salts thereof.

10. A process for making a compound of Formula I which are ethers defined in Claim 1 which comprises the reaction of codeine or morphine with the appropriate alkyl chloride in the presence of sodium hydride in THF.
11. A pharmaceutical composition comprising a compound of Formula I as defined in any of Claims 1-9 together with a pharmaceutically acceptable diluent or carrier12. A pharmaceutical composition according to Claim 11 adapted for oraladministration.
13. A pharmaceutical composition according to Claim 11 adapted for parenteraladministration.
14. A pharmaceutical composition according to Claim 11 adapted for delayed release.
15. A compound of Formula II

wherein R1 = H (morphine analogue), CH3 (codeine analogue) R2 = H, alkyl group of 1 to 4 carbon atoms, allyl, cyclopropylmethyl R3 = a group -O-CH2-R4 (ether) -O-COCH=CHR4 (cinnamate) wherein R4 = wherein X1, X2, X3, X4 and X5 which may be the same or different are separately selected from H, an alkyl group of 1 to 4 carbon atoms, NH2, NO2, alkoxy group of 1 to 4 carbon atoms, hydroxy, halogen, N-alkyl group of 1 to 4 carbon atoms, morpholine, a group COR5 wherein R5 is H, OH, O-alkyl where alkyl is from 1 to 4 carbon atoms, or one of X1 and X2, X2 and X3, X3 and X4 or X4 and X5 together with an alkylene group optionally interrupted by O, S or N of up to 5 atoms in length complete a ring with the proviso that not all X1, X2, X3, X4 and X5 are hydrogen and pharmaceutically acceptable salts thereof.
16. The use of a compound according to any one of Claims 1-9 or Claim 15 for the manufacture of a medicament for use in the alleviation of pain.
17. A method of alleviating pain in an individual comprising administering a therapeutically effective amount of a compound according to any one of Claims 1-10 or Claim 15 to the individual.