3,4-Diazanorcaradienes and 4,5-dihydropyridazines as precursors for new stable azomethine ylides

Article abstract of DOI:10.1016/S0040-4020(99)00516-5

The synthesis of a new class of stable coloured azomethine ylides 3 derived from 3,4-diazanorcaradienes is reported, which under acid catalysis are transformed to again coloured stable azomethine ylides 4 containing a five-membered 1-aza-1,3-cyclopentadiene skeleton. Azomethine ylides 3 in boiling methanol rearrange to 3,5-diazahomotropilidenes 8 in good yields.