Girisha; Kalluraya, Balakrishna; Vidyashree Jois, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2012, vol. 51, # 12, p. 1767 - 1770
cascade 6-endo-dig cyclizationreaction was developed for the switchable synthesis of halogen and non-halogen-functionalized pyrazolo[3,4-b]pyridines from 5-aminopyrazoles and alkynyl aldehydes via C≡C bond activation with silver, iodine, or NBS. In addition to its wide substrate scope, the reaction showed good functional group tolerance as well as excellent regional selectivity. This new protocol