Fused Diazepines. Synthesis of 2-Methyl-8-aryl-4,6-dihydro-5H-thieno[3',2':4,5]thieno[2,3-d][1,2]diazepin-5-ones

Heterocyclization of ethyl 2-acetyl(aroyl)-5-methylthieno[2,3-b]thiophene-3-acetates with hydrazine hydrate has been studied. A dependence of the reaction direaction on the nature of the substituent in the acyl fragment was established. The heterocyclization of ethyl 2-aroyl-5-methylthieno[2,3-b]thiophene-3-acetates leads to derivatives of thieno[3',2':4,5]thieno[2,3-d][1,2]diazepin-5-ones. The cyclization of ethyl 2-acetyl-5-methylthieno[2,3-b]thiophene-3-acetate with hydrazine hydrate forms a six-membered ring, viz. 2-aminothieno[3',2':4,5]thieno[2,3-c]pyridin-5(6H)-one.