Synthesis and Antiallergy Activity of [1, 3, 4]Thiadiazolo[3, 2-a]-1, 2, 3-triazolo[4, 5-d]pyrimidin-9(3H)-one Derivatives. I

抄録

A series of 6-substituted [1, 3, 4]thiadiazolo[3, 2-a]-1, 2, 3-triazolo[4, 5-d]pyrimidin-9(3H)-one derivatives 4a-z were synthesized from 5-substituted 1, 3, 4-thiadiazol-2-amines 5 by the following consecutive reactions : pyrimidine ring closure with bis(2, 4, 6-trichlorophenyl)malonate, nitration, chlorination, amination, hydrogenation and diazotization. The structure of 4 was confirmed by an alternate synthesis of 4, involving reaction of 5-subsituted 2-azido-1, 3, 4-thiadiazole 13 with ethyl cyanoacetate, followed by the Dimroth rearrangement and ring closure.The antiallergic activities (anti-passive peritoneal anaphylaxis, anti-passive cutaneous anaphylaxis and anti-slow reacting substance of anaphylaxis activities) of the products were evaluated.