Phthalazines cathodic reduction

LAH converts l-alkylpyridazin-6-ones (60) into the corresponding 1,6-dihydropyridazines (57 R = Me, R = H), whereas excess reagent reduces 4,5-dihydropyridazin-6-ones (61) to a mixture of 1,4,5,6-tetrahydro- (62) and hexahydro-pyrazines (63).2 Cinnolines (64) and phthalazines (66) both undergo ring opening during cathodic reduction, giving diamines (65) and (67), respectively. ... 

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