Pyridazines electrochemical reduction

Alkylation of pyridazino[4,5- i]pyridazines is possible by electrochemical reduction in THF at — 1.2 V in the presence of methyliodide to afford the 4,5-dimethyl derivative quantitatively... 

Lund studied the electrochemical reduction of substituted pyridazines and reported that reduction of 3,6-diphenylpyridazine gave the 1,4,5,6-tetrahydro derivative 75.130 This is probably produced through the intermediacy of 4,5-dihydropyridazine 28a since, according to Lund, neither the 1,2- nor the 1,4-dihydro tautomers are expected to be reduced further under the reaction conditions used [Eq. (20)]. 

The reduction of a number of pyridazines was treated in Part I1 later electrochemical investigations296 confirmed that the initial reduction consumed two electrons and the primary product was suggested to be 1,2-dihydropyridazine, which tautomerized to the 1,4-dihydro derivative hydrolysis with ring opening followed. 

Novel pyrrole C-nucleosides 233 were synthesized in two steps by cycloaddition of alkynyl C-nucleosides 231 to dimethyl l,2,4,5-tetrazine-3,6-dicarboxylate 150 <1994AP365>, followed by extrusion of nitrogen from the resultant pyridazine C-nucleosides 232 using electrochemical and/or chemical reduction (Scheme 59) <2004TL1031>. 

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