Photoinduced transformations. Part XXXXI. Photoinduced rearrangement of (22S,25S)-N-acetyl-5α-veratra-8,13(17)-dienine-3β,11β,23β-triol 3,23-diacetate 11-nitrite to two spiro-isoxazolines

Abstract

Photolysis of the title nitrite (9) in toluene with Pyrex-filtered light or monochromatic light (362 ± 4 nm) afforded two isomeric spiro-isoxazolines, (10) and (11), designated photo-TVDTN and isophoto-TVDTN. Only the former was obtained pure and its structure was deduced from spectral evidence. The structure of the latter, obtained only as a mixture with photo-TVDTN, was inferred from spectra. The present results, in conjunction with those in the preceding paper, indicate that the presence of absence of a 5,6-double bond has little effect on the formation of these isoxazolines.