o.Formylarylazomethylenetriphenylphosphoranes: A facile thermally promoted rearrangement to 3-oxo-indazoline and 4-oxo-dihydroquinazoline derivatives
作者:A. Alemagna、P. Del Buttero、E. Licandro、S. Maiorana、A. Papagni
DOI:10.1016/s0040-4020(01)96683-9
日期:——
s carrying an electron withdrawing group on the ylidic carbon undergo thermal intra molecular cyclization to 3-oxo-indazolin-2-yl-methylenetriphenylphosphorane derivatives. The latter compounds, and their 1-alkyl derivatives, in turn, undergo thermal and/or acid catalyzed rearrangement to 4-oxo-l,4-dihydroquinazoline derivatives and PPh3. Some possible reaction mechanisms are discussed, and some synthetic
The coupling of diazonium salts fromisaticacids with alkoxycarbonylmethylenephosphoranes leads directly to 3-oxo-indazolin-2-yl-(alkoxycarbonyl) methylenetriphenylphosphoranes, while coupling with methyl 2-chloroacetacetate gives 2-[2-(methoxycarbonyl-chloromethyliden)hydrazino] -phenyl-glyoxylic acid.