Preparation of pyridazine, useful for producing active substances, comprises hydrolyzing maleindialdehyde diacetals in the presence of an acid catalyst to give maleic dialdehyde and reacting the maleic dialdehyde solution with hydrazine

摘要

Preparation of pyridazine from maleic dialdehyde and hydrazine comprises hydrolyzing maleic dialdehyde diacetals in the presence of an acid catalyst to give maleic dialdehyde, separating the formed alcohol and reacting the maleic dialdehyde solution with hydrazine. An independent claim is included for a pyridazine obtained as above with purity >= 99.3 wt.%, chloride content 2 wt.ppm and hydrazine content 10 wt.ppm.