Some reactions of 2-oxocyclopentanedithiocarboxylic acid and 3-methyl-5-oxo-1-phenyl-Δ2-pyrazoline-4-dithiocarboxylic acid

Abstract

The title dithiocarboxylic acids, (1) and (6) respectively, were obtained by substitution reactions of the corresponding cyclic ketones with carbon disulphide in the presence of aqueous alkali. The acid (1) reacted with hydrazine to give 1,4,5,6-tetrahydrocyclopenta[c]pyrazole-3(2H)-thione (2); the acid (6) simply afforded the hydrazide (11). Treatment of the acid (6) with aldehydes yielded the 1,3-dithietan-2-ylidenepyrazolines, (7)–(10). The acids (1) and (6) both gave benzodithiol-2-ylidene derivatives [(3), (4), and (12)] when treated with 2,4-dinitrochlorobenzene or similar reagents.