TRANSFORMATION OF 1,2-DITHIOLE-3-THIONES INTO l,6,6a lambda~4-TRITHIAPENTALENES via REACTION WITH BROMOETHANONES

摘要

We report the reactions of derivatives of 5-amino-3-thioxo-3H-1,2-dithiole-4-carboxylic acid 1 with bromoethanones and acylation agents.Two different routes were used to obtain the products,3-(acylmethylidene)-3H-1,2-dithioles 4.These compounds were synthesized by acylation of compounds 1 on the amino group,followed by the reaction with bromoethanones and excess of triethylamine.Another method was based on the inverted order of the mentioned reaction steps and in absence of a base.The treatment of 4 with thionyl chloride gave new unsaturated fused lactones 13 whereas thionation led to desired 1,6,6a lambda~4-tri-thiapentalenes 5.The structures of products and the reaction mechanisms are discussed.