Condensation of 5(3)-amino-3(5)-arylpyrazoles with 4-hydroxy-6-methylpyran-2-one leads to 5,7-dimethyl-2-arylpyrazolo[1,5-a]pyrimidines, 5-alkoxycarbonylmethyl-7-methyl-2-arylpyrazolo[1,5-a]pyrimidines and their isomeric 7-alkoxycarbonylmethyl-5-methyl-2-arylpyrazolo[1,5-a]pyrimidines. These compounds result from competitive reactions and from different cyclization pathways. Structure and mechanism of formation of these new products are reported. (C) 2011 Elsevier Ltd. All rights reserved.
Aggarwal, Ranjana; Rani, Chinu; Kumar, Rajiv, Indian Journal of Heterocyclic Chemistry, 2015, vol. 24, # 4, p. 419 - 428