Syntheses of Cyclic Hydroxamic Acids and Lactams with 2, 3??dioxo??1, 4??benzoxazine skeleton

H Hartenstein, D Sicker

Index: Hartenstein, H.; Sicker, D. Journal fuer Praktische Chemie/Chemiker-Zeitung, 1993 , vol. 335, # 4 p. 359 - 362

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Citation Number: 6

Abstract

Abstract Ethyl 2-nitrophenyl oxalate (1 a) and its 5-methoxy derivative (1b) were subjected to catalytic hydrogenations over 3% Pt (S) on carbon in different solvents. Thus, hydrogenation in acetic acid yielded 4-hydroxy-2, 3-dioxo-1, 4-benzoxazine (2a) and its 7-methoxy derivative (2b) by reductive cyclization, the dehydro forms of the naturally occurring cyclic hydroxamic acids DIBOA and DIMBOA from Gramineae. In contrast, hydrogenation of ...