Patent GB-1379940-A (GB)
Title: Carbazole derivatives
IPC: C07D209/86
Filed: 1972-12-29
Abstract: 1379940 1-Aminoalkyl-1,2,3,4-tetrahydrocarbazoles F HOFFMANN-LA ROCHE & CO AG 29 Dec 1972 [30 Dec 1971] 60039/72 Heading C2C 1-Aminoalkyl-1,2,3,4-tetrahydrocarbazoles of the general formula wherein R 1  is a hydrogen or halogen atom or a trifluoromethyl, C 1-7  alkyl, cyano, hydroxy, C 1-7  alkoxy or C 1-7  alkylthio group, R 2  is a hydrogen or halogen atom, R 3  is a hydrogen atom or a C 1-7  alkyl group which may be phenyl-substituted, R 4  is a hydrogen atom or a C 1-7  alkyl group, each of R 5  and R 6  is a hydrogen atom or C 1-7  alkyl group or R 5 R 6 N- is a piperazino group optionally substituted by a C 1-7  alkyl or C 1-7  hydroxyalkyl group and n is 0 or 1, and acid addition salts thereof, which are novel except when R 1  is a hydrogen atom, are prepared (a) by reacting a 1-(substituted alkyl) - 1,2,3,4 - tetrahydrocarbazole of the general formula wherein X is a leaving atom or group, with ammonia or an amine of the general formula R 5 R 6 NH; (b) by reacting a phenylhydrazine of the general formula or an acid addition salt thereof with a 2-amino alkyl-cyclohexanone of the general formula or with an acid addition salt thereof in the presence of a Lewis acid; (c) when R 4  is a hydrogen atom if n is 0, by reducing an amide of the general formula wherein m is 0 or 1; (d) when R 1  is a hydroxy group and/or R 3  is a hydrogen atom, by cleaving off the protecting group(s) in a protected 1-aminoalkyl-1,2,3,4-tetrahydrocarbazole of the general formula wherein R 10  is as R 1  or a hydroxy group substituted by a hydrolysable or hydrogenolysable protecting group and R 30  is a C 1-7  alkyl group which may be phenyl-substituted or a hydrolyssable or hydrogenolysable protecting group, at least one of R 10  and R 30  containing a protecting group, or in an acid addition salt thereof; (e) when R 1  is other than a cyano group and each of R 5  and R 6  is a hydrogen atom, by reducing a nitrile or azide of the general formula wherein R 11  is as R 1  with the exception of a cyano group and A is a -CH(R 4 )CN or (f) when each of R 3 , R 5  and R 6  is a C 1-7  alkyl group, by alkylating the corresponding compound in which one of R 3 , R 5 , and R 6  is a hydrogen atom or an acid addition salt thereof; and (g) when R 4  is a hydrogen atom and n is 0, by reacting a 1,2,3,4-tetrahydrocarbazole of the general formula or an acid addition salt thereof with formaldehyde and an acid addition salt of ammonia or an amine of the third general formula above; and, in optional sequence, optionally replacing a chlorine or bromine atom denoted by R 1  by a cyano group, splitting a resulting racemate into the optical antipodes, and/or converting a resulting base into an acid addition salt thereof or vice-versa. Amides of the sixth general formula above in which m is 0 are prepared by reacting the corresponding carboxylic acid with phosphorus pentachloride, followed by ammonia or an amine of the third general formula above. Amides of the sixth general formula above in which m is 1 and R 4  is a hydrogen atom are prepared by reducing the corresponding 1,2,3,4- tetrahydrocarbazole-1-carboxylic acid alkyl ester with lithium aluminium hydride, treating the resulting 1-hydroxymethyl derivative with p-toluenesulphonyl chloride, reacting the resulting 1 - p - toluenesulphonyloxymethyl derivative with sodium cyanide, hydrolysing the resulting 1-cyanomethyl derivative with ethanolic KOH and reacting the resulting 1-carboxymethyl derivative with ammonia or an amine of the third general formula above in the presence of triethylamine and isobutyl chloroformate. 6 - Benzyloxy - 1 - dimethylaminomethyl- 1,2,3,4-tetrahydrocarbazole hydrochloride is prepared by treating 6-benzyloxy-1,2,3,4-tetrahydro-1-carboxylic acid with phosphorus pentachloride, followed by dimethylamine, and converting the resulting N,N-dimethyl-1-carboxylic acid amide derivative to the desired compound by a process analogous to (c) above, followed by salification. Pharmaceutical compositions having antidepressant and appetite-inhibiting activity comprise, as active ingredient, a 1-aminoalkyl- 1,2,3,4-tetrahydrocarbazole of the first general formula above or acid addition salt thereof, together with a compatible pharmaceutical carrier.