Facile synthesis of pyrazolo[1, 5-a]pyridopyrazin-one via Smiles rearrangement or direct cyclization. Issue 12 (25th March 2015) - Xiao, Youxin
Abstract: A facile access to pyrazolo[1, 5- a ]pyridopyrazin-one is presented via Smiles rearrangement or direct cyclization. The method allows the convenient construction of a novel biaryl lactam in moderate to excellent yields starting from easily available precursors (18 examples, 75–97% yield). When R is an aryl group, two regioisomeric products were obtained, Smiles rearrangement product and direct cyclization product, but when R is alkyl or benzyl, Smiles rearrangement product was afforded selectively. In order to prove the proposed mechanism, intermediate6k was trapped. Graphical abstract: