Preparation of 1,5-Dihydropyrazolo[3′,4′:5,6]pyrano[3,4-<i>b</i>]pyridines via a Microwave-Assisted, Palladium-Catalyzed Regioselective C–H Heteroarylation of Electron-Rich Pyrazoles
作者:Aaron T. Garrison、Elizabeth S. Childress、Dexter C. Davis、Craig W. Lindsley
DOI:10.1021/acs.joc.9b00144
日期:2019.5.3
Here we report the first synthesis of a family of novel heterocyclic compounds based on a 5-dihydropyrazolo[3',4':5,6]pyrano[3,4-b]pyridine core. In the course of our drug discovery programs, we had need to access the previously unknown 5-dihydropyrazolo[3',4':5,6]pyrano[3,4-b]pyridine core. Initial attempts required long reaction times, which led to degradation and side products. Reaction optimization identified a Pd-catalyzed, microwave-assisted C-H heteroarylation protocol for the rapid, general, and high yielding synthesis of this tricyclic core (as well as related analogs) suitable to drive optimization efforts.