Tetrahedron

Synthesis of oxazines and thiazines by cyclodehydration of hydroxy amides and thioamides

P Wipf, GB Hayes

Index: Wipf, Peter; Hayes, Gregory B. Tetrahedron, 1998 , vol. 54, # 25 p. 6987 - 6998

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Citation Number: 50

Abstract

Dihydro-1, 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 thiazepine heterocycle, ...