Collect. Czech. Chem. Commun. 1987, 52, 2953-2960

Preparation and photochemistry of 3-methoxycarbonyl substituted condensed isoxazolines

Vladimír Oremusa, Lubor Fišeraa and Hans-Joachim Timpeb

a Department of Organic Chemistry, Slovak Institute of Technology, 812 37 Bratislava, Czechoslovakia
b Department of Photochemistry, Technical University, Merseburg, G.D.R. - 42


The 1,3-dipolar cycloaddition of methoxy- and ethoxycarbonylnitriloxide to 2,3- and 2,5-dihydrofuran, 2,3-dihydropyrane, 7-oxabicyclo[2,2,1]-2-heptene, and 1,3-dioxep-5-ene derivatives is described. The condensed isoxazolines Ia, IIIa, Va, Vb are rearranged on irradiation to give the methoxycarbonyl substituted enaminoaldehydes IIa, IVa, VIa, VIb, respectively. The photolysis of VIIc, VIIIa, VIIIc is connected with destruction. The quantum yields of the photorearrangement are higher than those of the phenyl substituted derivatives but lower than those of the corresponding cyano derivatives. The enaminoaldehydes IIa and VIa have been used for preparation of new heterocyclic pyridazino[4,5-d]oxazine (IX) and pyridazino[7,8-d]-2,4,6-dioxazocine (X) systems, respectively.