Abstract
1-Iminopyridinium ylide reacted with diketene to give 1-(N-acetoacetylimino)-pyridinium ylide (VI), which, on treatment with sodium ethoxide, was transformed to 3-acetyl-2-hydroxypyrazolo [1, 5-a] pyridine (XI). On the other hand, reaction of diketene with 1-(N-methylimino) pyridinium ylide afforded directly 3-acetyl-1-methylpyrazolo [1, 5-a] pyridin-2-one (VIII). Reaction of diketene with 1-iminoquinolinium ylide (XIII) and 2-iminoisoquinolinium ylide (XVI) gave rise to 3-acetyl-2-hydroxypyrazolo [1, 5-a] quinoline (XV) and 3-acetyl-2-hydroxypyrazolo [1, 5-a] isoquinoline (XVII), respectively.
