Cinnolines cathodic reduction

The reduction of compounds suitably substituted with reducible functional groups can be advantageously used for the preparation of heterocyclic ring systems 15 5 The guiding principle here is to form a nucleophilic center in the molecule by cathodic reduction of a functional group and then have this to react with an electrophilic center (which may also be formed in an electrochemical process or be present in the starting material) suitably positioned for ring closure. Thus, 2,2-dinitrobiphenyl can be reduced to benzo[c] cinnoline in acid solution ... 

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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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

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