Thermal rearrangements of C-(4-Oxo-4H[1]benzopyran-3-yl)-N- phenylnitrone-a route to novel quinolino[2,3-b] chroman-12-ones

Article abstract of DOI:10.1016/S0040-4039(98)01362-8

C-(4-Oxo-4H[1]benzopyran-3-yl)-N-phenylnitrones (1a-c) undergo facile rearrangements on refluxing in benzene, yielding 2-(N-phenylamino)-4-oxo- 4H[1]-benzopyran-3-carboxaldehydes (2a-c,70%) and 3-(phenyliminomethylene)- chroman-2,4-diones (3a-c, 25%). 2a-