A new method for the preparation of 2‐carhoalkoxypyrazolo [5,1 ‐B] quinazolin‐9(1H)ones

Abstract Anthranilic acid hydrazides were condensed with acetylene diesters, and the intermediate adduets were identified as aeylhydrazones of oxalacetic diester. These anthranilic hydrazones could be thermally cyclized to 2‐carboalkoxypyrazolo[5,1‐ b ] quinazolin‐9(1 H )ones.