5-Methyl-4-oxo-4,6-dihydro-3H-pyridazino[4,5-b]carbazole-1-carbonitrile

The title compound was prepared in excellent yield from 5-methyl-4-oxo-4,6-dihydro-3 H-pyridazino[4,5- b]carbazole-1-carbaldehyde by treatment with hydroxylamine hydrochloride in formic acid without isolation of the intermediate oxime.