Abstract
The synthesis of 2'-hydroxy-2-benzyl-5, 9-dimethy1-6, 7-benzomorphan (1a) starting from tyrosine was studied.
Tyrosine was converted to 3-benzylamino-4- (p-methoxyphenyl) -2-butanone (6) via four steps. Reaction of (6) with 3-ethoxy-1-methylpropylmagnesium bromide gave 2-benzylamino-6-ethoxy-1- (p-methoxyphenyl) -3, 4-dimethyl-3-hexanol (7). Dehydration of (7) afforded 2-benzylamino-6-ethoxy-1- (p-methoxyphenyl) - 3, 4-dimethyl-3-hexene (8). (8) was converted to 2-benzylamino-4- (2-ethoxyethyl) -3, 4-dimethy1-6-methoxy-1, 2, 3, 4-tetrahydronaphthalene (9) on cyclization in polyphosphoric acid. Treatment of (9) with HBr gave (1a).
Cis-trans isomers of (8) and stereoisomers of (9) were separated by column chromatography and relationships between these isomers and those of (la) were discussed.
