Photochemical Conversion of Isoxazoles to 5-Hydroxyimidazolines.

Photochemical conversion of isoxazole I to 5-hydroxyimidazoline VII proceeded via the trapping of the photogenerated acylazirine III with amines under UV light irradiation. This is the first report of the efficient synthesis of 5-hydroxyimidazolines that are not readily accessible by other means. 5-Hydroxyimidazolines were also converted into multisubstituted imidazoles in one step by treatment with trifluoroacetic anhydride (TFAA) and 2,6-lutidine in dichloromethane.