Ring Opening of 2-(Benzylamino)-2H-1,4-benzoxazin-3(4H)-ones and 2-Bromo-2H-1,4-benzoxazin-3(4H)-ones
作者:Janez Ilaš、Danijel Kikelj
DOI:10.1002/hlca.200890069
日期:2008.4
Substituted 2-(benzylamino)-2H-1,4-benzoxazin-3(4H)-ones are unstable under alkaline and acidic conditions, undergoing opening of the benzoxazinone ring. 2-Bromo-2H-1,4-benzoxazin-3(4H)-ones show similar degradation under alkaline conditions, while replacement of Br at C(2) to give 2-hydroxy-2H-1,4-benzoxazin-3(4H)-ones was observed only under mild alkaline conditions. Mechanisms of ringopening and degradation
取代的2-(苄氨基)-2 H -1,4-苯并恶嗪-3(4 H)-在碱性和酸性条件下不稳定,并经历苯并恶嗪酮环的打开。2-Bromo-2 H -1,4-苯并恶嗪-3(4 H)-在碱性条件下表现出相似的降解,而在C(2)处取代Br则得到2-羟基-2 H -1,4-苯并恶嗪仅在弱碱性条件下观察到-3(4 H)-one。提出了开环和降解为2-氨基苯酚衍生物的机理。
A convenient synthesis of 3,4-dihydro-1,4-benzoxazin-2-ones
作者:Nace Zidar、Danijel Kikelj
DOI:10.1016/j.tet.2008.04.010
日期:2008.6
3,4-Dihydro-1,4-benzoxazin-2-one was prepared for the first time by catalytic hydrogenation of 4-benzyl-3,4-dihydro-1,4-benzoxazin-2-one. A simple and efficient synthesis of 4-benzyl- and 4-alkyl-3,4-dihydro-1,4-benzoxazin-2-one derivatives from ethyl 2-(2-hydroxyphenylamino)acetate and aldehydes is described. Some considerations regarding the reactivity of 3,4-dihydro-1,4-benzoxazin-2-ones are given. (C) 2008 Elsevier Ltd. All rights reserved.