CATALYTIC ACTION OF AZOLIUM SALTS - IX - SYNTHESIS OF 6-AROYL-9H-PURINES AND THEIR ANALOGS BY NUCLEOPHILIC AROYLATION CATALYZED BY IMIDAZOLIUM OR BENZIMIDAZOLIUM SALT

In the presence of 1,3-dimethylimidazolium iodide (1), 6-chloro-9-phen yl-9H-purine (7) and 4-chloro-5,6-dimethylpyrrolo[2,3-d]pyrimidines 40 -42 underwent nucleophilic aroylation with arenecarbaldehydes (5) to g ive the corresponding fused aroylpyrimidines 8 and 43-45. 1,3-Dimethyl benzimidazolium iodide (2) was an effective catalyst for the similar s ynthesis of aroyl-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidines 16-21. In the synthesis of 4-aroyl-1H-pyrazolo[3,4-d]pyrimidines 26-32, both azolium salts 1 and 2 were effective as catalysts. Moreover, 4-aroyl-7 H-pyrrolo[2,3-d]pyrimidines 43-45 were obtained in good yields via the 4-tosyl derivatives, in the presence of catalytic amounts of sodium p -toluenesulfinate (46) and the imidazolium salt 1, This catalytic aroy lation,vas found to be a facile and useful method for the synthesis of 6-aroyl-9H-purines and their analogues.