Heterocyclic synthesis with nitriles: Syntheses of some novel pyrazolo[1,5-a]pyrimidine and Pyrrolo[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine Derivatives

3,5-Diamino-4-phenacylpyrazoles 1a , b react with the cinnamonitriles 2a , b to afford the novel 7-phenacylpyrazolo1,5-a]pyrimidine derivatives 4a – d , respectively. Compounds 4c , d undergo cyclization with trichloroacetonitrile to afford the novel tricyclic system pyrrolo-2′,3′:3,4]pyrazolo1,5-a]pyrimidine derivatives 5e , f , respectively.