V. Sosnovskikh, V. Moshkin, R. Irgashev
Nov 27, 2006
Citations
0
Influential Citations
20
Citations
Journal
Tetrahedron Letters
Abstract
Abstract Reaction of 3-(polyfluoroacyl)chromones with hydroxylamine proceeds via nucleophilic 1,4-addition followed by opening of the pyrone ring and subsequent cyclization to 4-(polyfluoroalkyl)-4 H -chromeno[3,4- d ]isoxazol-4-ols in good yields. On treatment with trifluoroacetic acid, the isoxazole ring of this annulated heterocyclic system opens to give 3-cyano-2-(polyfluoroalkyl)chromones. Reaction of 3-(polyfluoroacyl)chromones with hydroxylamine hydrochloride occurs only at the carbonyl carbon atom connected to the R F group to give the corresponding oximes in low yields.