Reactions of 2H-3,4-dihydro-1,4-benzoxazin-6(8aH)-ones with 2,4,6-trimethylbenzonitrile oxide, III

摘要

Regio-, stereo- and siteselectivity of the cycloadditions of trimethylbenzonitrile oxide with 2H-3,4-Dihydro-1,4-benzoxazin-6(8aH)-ones have been investigated. The structures of the obtained products were elucidated by means of homonuclear NOE difference spectroscopy and HMQC and HMBC spectra. The structure of 6-Benzyl-9a-methoxy-3-mesityl-9b-methyl-7,8,9a,9b-tetrahydro-3aH-1,2-oxazolo-4,5-h1,4-benzoxazin-4(6H)-on5was elucidated from a single crystal X-ray structure analysis at ambient temperature: C27H30N2O4, M=446.55g/mol, monoclinic, P21/c,a=10.372 (34) Å,b=11.908 (21) Å,c=20.040 (34) Å, β=97.16 (17)°,V=2455.8 (1.9)Å3,Z=4,dc=1.208g/cm3, μ=0.08mm−1,