Preparation and photochemistry of 3-cyanosubstituted condensed isoxazolines containing an oxygen atom

Abstract

The 1,3-dipolar cycloaddition of cyanonitrile oxide to 2,3- and 2,5-dihydrofurane, 7-oxabicyclo[2,2,1]-2-heptene and derivatives of 1,3-dioxep-5-ene is described. The condensed isoxazolines Ia, IIIa, Va, Vc, Vd thus prepared are rearranged on irradiation into cyanosubstituted heterocyclic enaminoaldehydes IIa, IVa, VIa, VIc. The quantum yields of the photorearrangement of cyanoderivatives are higher than those of the phenyl derivatives, being within the limits from 0·068 to 0·19. The reaction of II with hydrazine gives the derivative IX of oxazino[4,5-d]pyridazine.

Novel reaction of [bis(acyloxy)iodo]arenes

“…§ All spectroscopic and analytical data were consistent with the structures assigned. Compounds 7, 10 8, 11,12 9, 12 10, 12 11, 13 12 11 and 14 18 corresponded to materials described previously. ¶ Note that decarboxylation of acid 4 was observed at 170 °C/25 Torr.…”

“…The net result of this process corresponds to a formal breaking of five bonds (as indicated in Scheme 3) with concomitant generation and dimerization of cyanogen oxide 6. Note that, previously, nitrile oxide 6 was only generated (i) from α-chloroα-cyanoformoxime by base treatment [11][12][13] and (ii) from 3-aminofurazan carboxylic acid by diazotization. 10 1,3-Dipolar cycloaddition 14 of nitrile oxide 6 generated from carboxylate 5 was examined with styrene, cyclopentene, cyclohexene, 2,5-dihydrofurane, and phenylacetylene.…”