Zur Umsetzung von 8a-Methoxy-3,4-dihydro-2H-1,4-benzoxazin-6(8aH)-onen mit Diazoalkanen, 2. Mitt.

摘要

8a-Methoxy-3,4-dihydro-2H-1,4-benzoxazin-6(8aH)-ones2undergo regio- and stereospecific 1,3-dipolar cycloaddition reactions with diazomethane or diazoethane to yield 3,4,6a,9,9a,9b-hexahydro-pyrazolo3,4-h1,4benzoxazin-6(2H)-ones3, which slowly isomerize in solution to give the 3,4,8,9,9a,9b-hexahydro-pyrazolo3,4-h1,4benzoxazin-6(2H)-ones5. The carbon of the diazoalkane dipole is attached to carbon C-8 of the benzoxazinone. The structures of the obtained products were determined by1H- and13C-NMR spectroscopy. An X-ray crystal structure analysis of3 awas carried out at room temperature:C11H15N3O3,Mr=237.26, orthorhombic, Pc21n,a=9.173 (5),b=9.133 (4),c=13.281 (6),V=1112.6 (9) Å3,Z=4,dx=1.416 g/cm−3, μ=0.93 cm−1,R=4.33,Rw=3.95 (919 observations, 168 parame