Synthesis of Some 2,6-Diamino-9-arylpurines, 2,6-Diamino-9- aryl-8-azapurines and Some Related 5-Phenylazopyrimidines

Department of Applied Chemistry, University College of Science and Technology, Calcutta-9 Manuscript received 4 August 1972; accepted 17 February 1973 Synthesis of some 2,6-diamino-9-arylpurines,2,6mino-9-ary1-8-azapurines and 2,4-diamino­6-arylamino-5-phenylazopyrirnidines have been reported. 9-Arylpurines were prepared by the cyclization with formamide of appropriate 6-arylamino-2,4,5-triaminopyrimidine bisulphite. The 9-aryl-8-azapurines were prepared by the cyclization of the above 2,4,5-triasninopyrimidine bisulphites with nitrous acid. The 6-ary/amino-2,4,5-triaminopyrimidine bisulphites were obtained by the reduction of the 2,4-diamino-5-nitroso-6-arylarninopyrimidines with sodium hydrosulphite. The 5-phenylazopyrimidines were synthesized by the reaction of appropriate 2,4-diamino-6-aryl­aminopyrimidines with benzenediazonium chloride. The assignment of structures of these 9- arylpurines and 9-aryl-8-azapurines were based upon their lack of acidic character