Kovalyova S. Phosphorylation of 2-aminothiophene derivatives with phosphorus (III) halides

Derivatives of N,N-dimethylamino-N'-(2-thienyl)-formamidine were shown to be phosphorylated regiose-lectively at C5 or C3 position of thiophene depending on the arrangement of other substituents in the heterocycle. Based on C5-phosphorylated N,N-dimethylamino-N'-(2-thienyl)formamidines the methods for synthesis of new C-phosphorylated derivatives of 2-amino-3-thiophenecarbo-xylic acids and thieno[2,3-b]pyrimidones were elaborated. It was found that C3-phosphorylated N,N-dimethylamino-N'-(2-thienyl)formamidine is readily accessible reagent for the synthesis of new heterocyclic system - thieno-[2,4,1]diazaphosphinine. High nucleophilicity of C3 carbon atom in 5-alkoxycarbonyl-2-aminothiophene in respect to phosphorus (III) bromides allowed using N-substituted derivatives bearing exocyclic nucleophilic N-, O-, or C-centers in the nitrogen containing residue for preparing new fused phosphorus containing systems.