Studies on the heterocyclic compounds. XVIII. Syntheses of imidazo-(1,2-c)-and pyrimido(1,2-c)pyrimidine derivatives

Abstract

2, 4-Dichloro- (Ia, b) or 4, 6-dichloropyrimidine (II) was treated with aminoalcohols to afford the 4-substituted compounds. When these compounds were treated with thionyl chloride in tetrahydrofuran, cyclized compounds (Va, b, VIb, XIa, b, XIIb, XVa, b, XVII, XIX, and XXI) were obtained. In this reaction, some of the compounds (VIb and XIIb) were substituted by chlorine atom at the 5-position of pyrimidine ring. By the reaction of compound XXI with alkaline solution under a mild condition, ring opening of the pyrimidine occurred to give imidazolidine derivatives (XXII and XXIII). The compounds Ia, b or II was treated with aminoacetal to afford 4-(2, 2-diethoxyethylamino) compounds, which were converted to imidazo[1, 2-c]pyrimidines (XXVIIa, b and XXXII) by the reaction with 6 N hydrochloric acid followed by cone. sulfuric acid. In this case, ring opened compound (XXXIII) was obtained as a minor product.