Synthesis of Structurally Related Purines: Benzimidazo[1,2-a]pyridines, Benzimidazo-[1,2-c]pyrimidines, and Pyrazolo-[1,5-a]pyrimidines
作者:Galal H. Elgemeie、Nadia H. Metwally
DOI:10.1007/s007060050025
日期:——
alkanones with 2-cyanomethylbenzimidazole afforded benzimidazo[1,2- a ]pyridines. Analogues reactions with 2-aminobenzimidazole and 5-aminopyrazoles afforded benzimidazo[1,2- c ]pyrimidines and pyrazolo[1,5- a ]pyrimidines.
The 13C and 1H NMR spectra of some pyrazolo[1,5-a]pyrimidine derivatives are discussed. All 13C resonances were unambiguously assigned by means of both 2D experiments and gated decoupled spectra from which one-bond and long-range 13C–1H coupling constants were determined. The literature assignments for H-5 and H-7 in the parent system have been revised and a simple method for distinguishing between