Pyridyl-acyl hydrazone

Chaur MN et al (2011) Configurational and constitutional information storage multiple dynamics in systems based on pyridyl and acyl hydrazones. Chem Eur J 17 248-258... 

Alkaline hydrolysis of 3-phenyl-l,2,4,5-tetrazine affords benzalazinc in 80% yield,285 while action of sodium carbonate on 3,6-bis(4-pyridyl)-l,2,4,5-tetrazine (1) affords the acyl-hydrazone 2 in 56 % yield.286 A mechanism for the alkaline hydrolysis of 1,2,4,5-tetrazines has been suggested.286... 

Dehydrogenation of a-pyridinealdehyde hydrazone (251) yields not a-pyridyldiazomethane (252) but the cyclic isomer l,2,3-triazolo[3,4-a]pyridine (253).1 A similar ring closure is observed in diazo group transfers onto alkyl or aryl(2-pyridyl)methyl ketone (254) in MeOH/KOEt.1 The diazo intermediate could not be isolated but 3-acyl[l,2,3]triazolo[3,4-a]pyridine (255) is obtained.1... 

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