Some further 2-(4-substituted 1-piperazinyl)acetamides derived from 6,11-dihydrodibenzo[b,e]thiepin. Transformations of 6,11-dihydrodibenzo[b,e]thiepin derivatives into anthraquinones, anthrones and anthracenes

Abstract

Reactions of the secondary amines I and VIII with chloroacetyl chloride gave the 2-chloroacetamides II and IX affording by substitution reactions with 1-methylpiperazine, 2-(1-piperazinyl)ethanol and 3-(1-piperazinyl)propanol in the title compounds III-V and X-XII. The starting amine VIII was prepared from the ketone XIV via XVII and VII. The product of 1,6-addition and the following dehydrogenation XVIII was obtained as a by-product of the reaction of XIV with 1-methyl-4-piperidylmagnesium chloride. Reaction of 2-fluorodibenzo[b,e]thiepin-11(6H)-one (XV) with sodium hydride in dimethylformamide and the following hydrolysis gave 2-fluoroanthraquinone (XXVII). An attempt at trapping the presumed dianion of the type B by treatment with methyl iodide and the following hydrolysis resulted in a mixture of XXVII and the anthracenes XXXI and XXXII. A similar reaction sequence starting from the ketone XIV gave the anthrones XXX and XXXIV, 9-methoxy-10-(methylthio)anthracene (XXXIII) (main product) and anthraquinone (XXVIII). Oxidation of XXXIII with m-chloroperbenzoic acid or hydrogen peroxide gave either the sulfone XXXV or XXXVI.