Zur Umsetzung von 8a-Methoxy-3,4-dihydro-2H-1,4-benzoxazin-6(8aH)-onen mit Diazoalkanen, 2. Mitt. |
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Authors: | Manfred Schubert-Zsilavecz Ferdinand Belaj Robert Ott |
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Affiliation: | (1) Institut für Pharmazeutische Chemie, Karl-Franzens-Universität, A-8010 Graz, Österreich;(2) Institut für Anorganische Chemie, Karl-Franzens-Universität, A-8010 Graz, Österreich |
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Abstract: | Summary 8a-Methoxy-3,4-dihydro-2H-1,4-benzoxazin-6(8aH)-ones2 undergo regio- and stereospecific 1,3-dipolar cycloaddition reactions with diazomethane or diazoethane to yield 3,4,6a,9,9a,9b-hexahydro-pyrazolo[3,4-h][1,4]benzoxazin-6(2H)-ones3, which slowly isomerize in solution to give the 3,4,8,9,9a,9b-hexahydro-pyrazolo[3,4-h][1,4]benzoxazin-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 a was 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, =0.93 cm–1,R=4.33%,Rw=3.95% (919 observations, 168 parameters).Herrn Prof. Dr. W. Fleischhacker zum 60. Geburtstag gewidmet |
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Keywords: | 1,3-Dipolar cycloaddition of 3,4-dihydro-2H-benzoxazin-6(8aH)-ones with diazoalkanes Hexahydro-pyrazolobenzoxazin-6(2H)-ones NMR-investigation X-ray analysis |
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