Highly polar potential metabolites of the neuroleptic agent oxyprothepin: Synthesis of 2-hydroxy-8-methylsulfonyl and 3-hydroxy-8-methylsulfonyl derivatives of 10-[4-(3-hydroxypropyl)piperazino]-10,11-dihydrodibenzo[b,f]thiepin

Abstract

The acid XI, obtained by reaction of (2-iodo-5-methoxyphenyl)acetic acid with 4-(methylsulfonyl)thiophenol (VIII) in dimethylformamide in the presence of potassium carbonate and copper, was transformed via intermediates XIIa-XIVa to compound XVa. Demethylation with boron tribromide afforded compound III, the potential metabolite of oxyprothepin (II). Its oxidation with hydrogen peroxide in acetic acid gave the sulfoxide XVII, which is a further potential metabolite. A reaction of 2-iodo-4-methoxybenzoic acid with VIII and potassium carbonate in dimethylformamide in the presence of copper afforded the acid XIX whose ester XXI was reduced with diborane to the alcohol XXII; hydrogenolysis to compound XXIII was also observed. The alcohol XXII was processed via compounds XXIV and XXV to the acid XXVI which was cyclized in a low yield to the ketone XIIb. A further processing via the intermediates XIIIb and XIVb led to compound XVb. Demethylation gave compound IV, another potential metabolite.