Construction of pyrazolo[1,5-<i>a</i>]pyrimidines and pyrimido[1,2-<i>b</i>]indazoles with calcium carbide as an alkyne source

Abstract

]indazoles are also synthesized under similar conditions using indazole-3-amine as a substitute for pyrazole-3-amine as a starting material. The method has salient features such as the use of an inexpensive and easy-to-handle alkyne source, commercially available substrates, wide functional group tolerance, a low-cost mediator, and simple workup procedures. This protocol can also be extended to gram-scale synthesis.