Studies on Pyrimidine Derivatives. II. Synthesis of Thiazolo [5, 4-d] pyrimidines and Related Compounds. (2).

Abstract

1) The reaction of 2-chloro-4-thiocyano-5-nitropyrimidine (I) with aq. NH₄OH, EtNH₂, thiourea, or sodium phenoxide gave 2, 4-disubstituted derivatives. The reaction of (I) with ethanolic NH₄OH and aniline respectively gave 2-amino-4-thiocyano-5-nitropyrimidine (V) and 2-anilino-4-thiocyano-5-nitropyrimidine (IX), and the reaction of (V) or (IX) with sodium alkoxide gave 2-amino-4-mercapto-(XIV) and 2-anilino-4-mercapto-5-nitropyrimidine (XV). 2) The reduction of (V) and (IX) afforded the corresponding 2-aminothiazolo [5, 4-d]-pyrimidines, and the reduction of (XIV) and (XV) gave 2, 5-diamino-4-mercapto-(XVII) and 2-anilino-4-mercapto-5-aminopyrimidine (XVIII), respectively. The cyclization of (XVII) and (XVIII) with formic acid, acetic anhydride, benzoyl chloride, or potassium methylxanthate, gave the corresponding 2-substituted (H, CH₃, C₆H₅, SH) thiazolo [5, 4-d]-pyrimidines. 3) In the presence of alkali, 2-aminothiazolo [5, 4-d] pyrimidines were hydrolysed to the 4-mercapto-5-aminopyrimidine derivatives via the (4-mercapto-5-pyrimidyl) ureas.