Chlorobenzene → 5-Methyl-6-[2-(4-pyridyl)-5-benzimidazolyl]-4,5-dihydropyridazin-3-one

Participants

Reaction Steps

A mixture of 17 g of isonicotinoyl chloride, 21.8 g of 5-methyl-6-(3,4-diaminophenyl)-4,5-dihydropyridazin-3-one ("IIa"; m.p. 195°-196°) and 400 ml of chlorobenzene is boiled for 2 hours. After having been cooled, the usual working up is carried out and, initially, an oily mixture of 5-methyl-6-(3-amino-4-isonicotinamidophenyl)- and 5-methyl-6-(3-isonicotinamido-4-aminophenyl)-4,5-dihydropyridazin-3-one is obtained, which is dissolved in 400 ml of acetic acid and boiled for 3 hours. After having been cooled, 5-methyl-6-[2-(4-pyridyl)-5-benzimidazolyl]-4,5-dihydropyridazin-3-one ("M"), dihydrate, m.p. 195°-198° (decomposition) is obtained. Dihydrochloride-dihydrate, m.p. 224°-227°. Methanesulphonate, m.p. 282°-285°.

Provenance & Evidence