Study of the heterocyclization of vic-substituted hydrazides of acetylenylpyrazolecarboxylic acids into N-amino pyrazolopyridinones

Article abstract of DOI:10.1002/jhet.5570390617

We report a new and efficient methodology to prepare N-amino pyrazolo[4,3-c]pyridin-4-ones 4 and N-amino pyrazolo[3,4-c]pyridin-4-ones 8 from vic-acetylenyl/hydrazido pyrazoles. The procedure involves the intermediate synthesis of methyl esters of acetylenyl-pyrazole carboxylic acids and the subsequent cyclization under a variety of conditions.