Collect. Czech. Chem. Commun. 1986, 51, 2167-2180

Photoinduced rearrangement of hydroxymethylisoxazolines, a route to enaminoaldehydes

Lubor Fišeraa, Nadezhda D. Kozhinab, Peter Oraveca, Hans-Joachim Timpec, Ladislav Štibrányia and Larisa A. Badovskayab

a Department of Organic Chemistry, Slovak Institute of Technology, 812 37 Bratislava, Czechoslovakia
b Department of Chemistry, Krasnodar Polytechnical Institute, Krasnodar, U.S.S.R.
c Department of Photochemistry, Technical University, DDR-4200 Merseburg, G.D.R.


3-Aryl-4-R-carbamoyl-5-hydroxymethylisoxazolines (IV) were synthesized by allowing R-NH2 amines with R = H, CH3, C3H7, C6H5C2H5, and NH2 to act on 3-(X-phenyl)-4-oxo-3a,4,6,6a-tetrahydrofuro[3,4-d]isoxazoles (III) with X = H, 4-CH3, 4-OCH3, 2-OCH3, 4-Cl, 2-Cl, 4-F, 2-F, 4-Br, 4-NO2, and 3-NO2. Exposed to radiation, the substances IV give Z-2-hydroxymethylamino-2-aryl-1-formylacrylamides (V) in good yields. The 4-Cl and 4-F substituted Z-derivatives V isomerize irreversibly to the E-derivatives VI if allowed to stand in solvent; the remaining derivatives V are stable. The quantum yields of the photoreaction are from 0.012 to 0.106 in dependence on the substituent X. In all cases where the compounds IV were used for the preparation of condensed heterocycles in conditions of acid-catalyzed reactions, lactones III were preferentially formed; the action of thionyl chloride on IV results in the formation of chloromethyl derivatives VIII, which do not undergo further cyclization.