Process for preparing 6,7-benzomorphans

Claim 1

A process for the preparation of a benzomorphan compound of the formula ##STR44## in which R is selected from the class consisting of methyl or ethyl; R 1 is selected from the class consisting of hydrogen atom, alkyl, haloalkyl and alkenyl groups containing up to seven carbon atoms, haloalkenyl and alkinyl groups containing up to four carbon atoms, cycloalkyl and cycloalkenyl groups containing up to seven carbon atoms, cycloalkylalkyl, cycloalkenylalkyl, cycloalkylidenealkyl and aralkyl groups containing up to nine carbon atoms, heteroarylalkyl compounds containing one oxygen atom and up to seven carbon atoms or heterocycloalkylalkyl groups containing one or two oxygen atoms and up to seven carbon atoms; and R 2 is selected from the class consisting of hydrogen atom, hydroxy groups, alkoxy groups containing up to three carbon atoms, alkoxyalkoxy groups containing up to four carbon atoms, nicotinoyloxy groups, lower alkanoyloxy groups, phenylalkanoyloxy groups containing up to nine carbon atoms or alkylaroyloxy groups containing up to nine carbon atoms; and pharmaceutically acceptable salts thereof; which comprises: A. reacting an aminoacid ester compound of the formula ##STR45## wherein R is as defined above, and R 3 is hydrogen or lower alkoxy, (1) with an acylating agent to form the corresponding acylamino ester compound VI; (2) alkylating the ester of compound VI to obtain the alkylamido ester compound VII; (3) saponifying the ester of compound VI or VII to obtain the corresponding acylamino or alkylamido acid compound VIII; (4) converting the acylamino or alkylamido acid compound VIII to an amidoacyl chloride compound IX; (5) converting the amidoacyl chloride compound IX by a Friedel-Crafts ring closure reaction to form a naphthalenone compund of the formula ##STR46## wherein R and R 3 are as defined above; R 4 is an acyl group; and R 5 is hydrogen alkyl, cycloalkyl or cycloalkylalkyl; (a) in the event that R 5 is hydrogen in the naphthalenone compound IV, alkylating the latter to convert R 5 to the more restricted meaning of alkyl, cycloalkyl or cycloalkylalkyl; B. reacting the naphthalenone compound IV (1) with an alkali metal acetylide to obtain an alcohol, ethinyl compound X; (2) partially reducing the ethinyl group of compound X to obtain an alcohol, ethylene compound XI; (3) isomerizing compound XI to obtain an hydroxy ethylidene compound XII; (4) (a) converting the hydroxy ethylidene compound XII by reduction to an hydroxy ethyl compound XIII and deacylating compound XIII to form an aminoalcohol compound XVI; or (b) (1) converting the hydroxy ethylidene compound XII to a tetrahydropyranyl ether compound XIV, reducing the compound XIV to compound XV and deacylating compound XV, followed by hydrolysis to form an aminoalcohol compound XVI; or (2) converting the compound XV by acid hydrolysis to compound XIII and deacylating compound XIII to an aminoalcohol compound XVI; or (c) deacylating and reducing compound XII to form an aminoalcohol compound XVI; and (5) converting the aminoalcohol compound XVI to a tetrahydronaphthalene compound having the formula ##STR47## wherein R and R 3 are as defined above, R 5 has the more restricted meaning defined above, and Y is a halogen; and C. subjecting the tetrahydronaphthalene to a ring closure in reaction in alkaline medium and treating the resulting closed ring compound to form the desired R 1 and/or R 2 substituents and/or salt derivatives of compound I, as above defined.