New Differently Functionalized Cyclopentenediones

Abstract

2-Allyl-2,4-dichloro-5-(2,4,6-trimethoxyphenyl)cyclopent-4-ene-1,3-dione reacted with highly nucleophilic secondary (diethylamine, morpholine, N-methylpiperazine, piperidine) and primary amines (allylamine) under mild conditions (methanol, 20°C, 24 h) to give products of substitution of the 4-chlorine atom in 60–87% yield. The reaction of the same compound with a weak nitrogen nucleophile, imidazole, afforded 4-(1H-imidazol-1-yl) derivative in a low yield (25%). Methionine methyl ester hydrochloride failed to react with 2-allyl-2,4-dichloro-5-(2,4,6-trimethoxyphenyl)cyclopent-4-ene-1,3-dione in methanolic potassium hydroxide; instead, 55% of 2-allyl-2-chloro-4-methoxy-5-(2,4,6-trimethoxyphenyl)cyclopent-4-ene-1,3-dione was obtained. The reaction with methyl 2-sulfanylacetate in the presence of sodium hydride produced methyl {[4-allyl-4-chloro-3,5-dioxo-2-(2,4,6-trimethoxyphenyl)cyclopent-1-en-1-yl]sulfanyl}acetate in 47% yield.