REACTIONS OF 2H-3,4-DIHYDRO-1,4-BENZOXAZIN-6(8AH)-ONES WITH 2,4,6-TRIMETHYLBENZONITRILE OXIDE .3.

Regio-, stereo- and siteselectivity of the cycloadditions of trimethyl benzonitrile oxide with 2H-3,4-Dihydro-1,4-benzoxazin-6(8aH)-ones have been investigated. The structures of the obtained products were eluci dated by means of homonuclear NOE difference spectroscopy and HMQC and HMBC spectra. The structure of dro-3aH-1,2-oxazolo-[4,5-h]1,4-benzoxa zin-4(6H)-on 5 was elucidated from a single crystal X-ray structure an alysis at ambient temperature: C27H30N2O4, M=446.55 g/mol, monoclinic, P2(1)/c, a = 10.372 (34) angstrom, b = 11.908 (21) angstrom, c = 20.0 40 (34) angstrom, beta = 97.16 (17)-degrees, V = 2455.8 (1.9) angstrom 3, Z = 4, d(c) = 1.208 g/cm3, mu = 0.08 mm-1, R = 0.0546.