Potential metabolites of the neuroleptic agents belonging to the 8-methylthio-10-piperazino-10,11-dihydrodibenzo[b,f]thiepin series; Synthesis of 2-hydroxy and 3-hydroxy derivatives

Abstract

The acid VI, prepared by reaction of potassium salts of (2-iodo-5-methoxyphenyl)acetic acid and 4-(methylthio)thiophenol in the presence of copper, was transformed via intermediates VII-IX to 2-methoxy-8-methylthio-10-piperazino-10,11-dihydrodibenzo[b,f]thiepins X and XI. Their demethylation with boron tribromide afforded 2-hydroxy derivatives of the neuroleptic agents methiothepin and oxyprothepin I and II. 11-Chloro-7-methoxy-2-methylthio-10,11-dihydrodibenzo[b,f]thiepin was subjected to substitution reactions with 1-methylpiperazine and 1-(ethoxycarbonyl)piperazine and gave piperazine derivatives XIII and XIV, out of which the latter gave the secondary amine XV by alkaline hydrolysis. The ethers XIII and XV were also cleaved with boron tribromide and gave 3-hydroxy derivatives of methiothepin (III) and its demethyl derivative IV. The phenols I, II, and IV are potential metabolites of the mentioned neuroleptic agents; compound III, which already was identified as a metabolite, disclosed properties of a strong and cataleptic neuroleptic agent with prolonged duration of the effects. The methoxy compounds X, XI, and XIII are practically devoid of the neuroleptic activity.