Photochemistry of 4‐ and 5‐Phenyl Substituted Isoxazoles.

Abstract

undergo phototransposition via a pathway involving only interchange of the N-2 and C-3 ring position. Additionally, the phototransposition of isoxazoles (I), (VI), and (IX) is accompanied by a photo-ring cleavage. The effect of a trifluoromethyl substituent on the photochemistry of 5-phenylisoxazole (I) is demonstrated with compound (XII). Irradiation of (XII) in methanol leads to a substantial decrease in the yield of phototransposition product (XIV) and to the formation of a mixture of the diastereomeric aziridines (XV) and (XVI). However, upon irradiation in acetonitrile, the only product obtained is (XIV). -(PAVLIK*, J. W.; MARTIN, H. S.; LAMBERT, K. A.; LOWELL, J. A.; TSEFRIKAS, V. M.; EDDINS, C. K.; KEBEDE, N.; J. Heterocycl. Chem. 42 (2005) 2, 273-281; Dep. Chem. Biochem., Worcester Polytech. Inst., Worcester, MA 01609, USA; Eng.) -H. Hoennerscheid 32-132

Photochemical rearrangements in organic synthesis and the concept of the photon as a traceless reagent

“…More generally in such reactions, a competition between both mechanisms is discussed. 22 All these reactions are part of the larger family of circumambulatory rearrangements. 23 Scheme 1.…”

Harnessing the Intrinsic Photochemistry of Isoxazoles for the Development of Chemoproteomic Crosslinking Methods

“…14 The isoxazole accesses high-energy intermediates reminiscent of photo-crosslinking motifs during these transformations, including nitrenes and azirines ( Scheme 1 ). 15 Indeed, muscimol and thiomuscimol, isoxazole-containing substrates of the gamma amino butyric acid receptor, have been shown to crosslink without exogenous photo-crosslinking groups, presumably due to the photoreactivity of the isoxazole. 16–18 Isoxazoles represent an untapped functional group in terms of their innate ability to act as a minimalist photo-crosslinker and their presence in a wide variety of molecules in medicinal chemistry.…”