Potential metabolites of tricyclic neuroleptics: 3,7-Dimethoxy and 7,8-dimethoxy derivatives of 10-(4-methylpiperazino)-10,11-dihydrodibenzo[b,f]thiepin
Reaction of 2-iodo-4-methoxybenzoic acid with 3-methoxythiophenol resulted in the acid II which was transformed via the alcohol III and the nitrile IV to [4-methoxy-2-(3-methoxyphenylthio)phenyl]acetic acid (V). Reaction of (2-iodophenyl)acetic acid with 3,4-dimethoxythiophenol gave the isomeric [2-(3,4-dimethoxyphenylthio)phenyl]acetic acid (XI). Acids V and XI afforded by cyclization the ketones VIa and VIb which were converted by reactions with 1-methylpiperazine and titanium tetrachloride to the enamines IXa and IXb. Reduction of these enamines with diborane led to the title compounds. Attempts to reduce the enamines with zinc in acetic acid resulted in hydrogenolysis, the main products being 2,3-dimethoxy- and 3,7-dimethoxy-10,11-dihydrodibenzo[b,f]thiepin (Xab).