Synthesis of oxazines and thiazines by cyclodehydration of hydroxy amides and thioamides
作者:Peter Wipf、Gregory B. Hayes
DOI:10.1016/s0040-4020(98)00341-x
日期:1998.6
3-oxazines and -thiazines were obtained by cyclodehydration of hydroxy amides and thioamides with PEG-linked Burgess reagent or under Mitsunobu conditions. Yields were generally higher with polymer-Burgess reagent, but both conditions failed to cyclize δ- and ε-hydroxy amide precursors. In contrast, Burgess reagent was successful for the cyclodehydration of δ-hydroxy thioamide to give the expected