Studies on pyridazin derivatives

Abstract

The present investigation deals with the synthesis of 4- [2,2'- dicyano-1-methylvinyl]-5,6-diphenylpyridazin-.3(21!)­ one (134) and some reactions on the product. (134) was synthesized by the reaction of 4-acetyl-5,6- diphenylpyridazin-3(21!)-one (59) with malononitrile in presence of pipridine as an organic biise. 4-[2,2' -dicyano-1-methylvinyl]-5,6-diphenylpyridazin-

3(21!)-one (134) reacted in the lactim form (135) with phosphorus oxychloride to give 3-chloro-4-[2,2'-dicyano-1- methylvinyl]-5,6-diphenylpyridazin (136). An attempt to undergo the reaction of 4-acetyl 3- chloro-5,6-diphenylpyridazin (137) and 4-acetyl-5,6- diphenyl-2-methylpyridazin-3(21!)-one (138) with malononitrile in presence of different bases failed Treatment of (134) with benzylmagnesium chloride in CN boiling benzene proceeded by 1,4-addition to the c ' CN system to give only one product (142).

When (134) was allowed to react with hydrazine hydrate it was excepted that nucleophilic attack of the hydrazine on the cyano group followed by ring closure will take place to give (145), but the reaction proceeded