FIRST PERMANENT OPENED FORMS IN SPIRO[INDOLINE-OXAZINE] SERIES - SYNTHESIS AND STRUCTURAL ELUCIDATION

The geometrical structure (TTC isomer), as well as the electronic dist ribution (quinoidic form), of the first permanent opened forms of spir ooxazines 5a and b have been determined by H-1 NMR spectroscopy and di pole moment measurements, The crystal structure of compound 5b has bee n determined by X-ray diffraction to confirm the conformations. Molar absorption coefficients were found to be 4.8 x 10(4) and 4.9 x 10(4) d m(3) mol(-1) cm(-1), respectively, for 5a and b.