Chemistry of acyl(imidoyl)ketenes

Thermal decarbonylation of 3-p-toluoylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4-trione affords (2-oxo-1,4-benzoxazin-3-yl)(p-toluoyl)ketene. The latter enters into the [4+2]-cycloaddition reaction withp-bromobenzylidene-p-anisidine to form 1-p-bromophenyl-2-p-methoxyphenyl-4-p-toluoyl-1,2-dihydropyrimidino[4,3-c][1,4]benzoxazine-3,5-dione. The molecular and crystal structure of the title compound was studied by X-ray diffraction analysis. For Part 1, see Ref. 6; for Part 2, see Ref. 5. Deceased Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 614–617, March, 1999.     

The [4+2]-cycloaddition of ketene containing both acyl and imidoyl groups to aldehyde: Synthesis,crystal and molecular structure of 1-p-bromophenyl-4-p-toluoyl-1, 3-dihydro-5H-[1,3]oxazino[4,3-c][1,4]benzoxazine-3,5-dione

Thermal decarboxylation of 3-p-toluoyl-1,2-dihydro-4H-pyrrolo[5,1-c][1,4]benzoxazine-1, 2,4-trione resulted in 2-oxo-2H-1,4-benzoxazin-3-yl(p-toluoyl)ketene; the latter under-goes [4+2]-cycloaddition withp-bromobenzaldehyde to form 1-p-bromophenyl-4-p-toluoyl-1, 3-dihydro-5H-[1,3]oxazino[4,3-c][1,4] benzoxazine-3,5-dione. The crystal and molecular structure of the latter has been studied by X-ray analysis.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1633–1636, September, 1993.