The chemistry of 5-oxodihydroisoxazoles. Part 19.1 The synthesis and photolysis of N-thioacylisoxazol-5(2H)-ones
作者:Rolf H. Prager、Max R. Taylor、Craig M. Williams
DOI:10.1039/a700646b
日期:——
5-Oxodihydroisoxazoles react with thiocarbonyl chlorides to afford
N-thioacylisoxazol-5(2H)-ones which lose carbon
dioxide under photochemical conditions and undergo intramolecular
cyclisation of the iminocarbene to afford thiazoles. However, in some
cases loss of carbon dioxide is accompanied by loss of sulfur, giving
1,3-oxazin-6-ones.
The chemistry of 5-oxodihydroisoxazoles. Part 22.1 The synthesis of 1,3-oxazin-6-ones from N-thioacylisoxazol-5(2H )-ones
作者:David S. Millan、Rolf H. Prager
DOI:10.1039/a804527e
日期:——
N-Thioacylisoxazol-5(2H)-ones, prepared by the reaction of thiocarbonyl chlorides with isoxazol-5(2H)-ones in the presence of base, are reduced by triphenylphosphine to afford 1,3-oxazin-6-ones and triphenylphosphine sulfide. If the thioacylation is carried out with phenyl chlorodithioformate, the thermal rearrangement of the intermediate, to again form the oxazin-6-one and sulfur, is so rapid that the use of the phosphine is not required. The presence of an ethoxycarbonyl group at C-3, or of a bromine atom at C-4 of the isoxazolone results in the formation of thiazoles.