A novel approach to 1-aryl-2-(p-tolylazo)alkenes from alkyl aryl ketones

Article abstract of DOI:10.1016/S0040-4020(98)00206-3

1-Aryl-2-(p-tolylazo)alkenes were synthesized starting from alkyl aryl ketones in good overall yield. The employed three-step procedure involves: i) α-p-tolylhydrazonylation of ketone enolates with tert-butyl p- tolylazosulfide 1; ii) selective reduction of the carbonyl function of the obtained α-p-tolylhydrazono ketones 3 with NaBH₄; iii) dehydration of the ensuing hydrazono alcohols 4 either in an Et₂O/dil. H₂SO₄ two-phase system or in pyridine/acetie anhydride.