取代双环4H-1,2-噁嗪衍生物的合成

Synthesis of Bicyclic 4H-1,2-Oxazine Derivatives

通过选择适当的催化剂和B r源,如脯胺酸/NBS,再以DMSO或THF为溶剂,与DBU作用,在双环化合物4H-1,2-苯并噁嗪-7-酮(1)的5,6-位区域选择性引入双键,首次成功合成了4,4 a,8,8 a-四氢苯并-1,2-噁嗪-7-酮-3-羧酸乙酯(1b),1b与在BF3.Et2O的催化下与对甲苯磺酰肼作用生成新化合物4,4 a,8,8 a-四氢苯并-1,2-噁嗪-7-酮-3-羧酸乙酯对甲苯磺酰腙(1 c),并通过光谱学对所合成的化合物进行了结构确定。

A new compound of 3 - ethoxycarbonyl -4, 4a, 8, 8a - tetrahydro - 1, 2 - benzoxazin -7 -one （lb） was synthesized from 3- ethoxyearbonyl-4, 4a, 5, 6, 8, 8a- hexahydro- 1, 2- benzoxazin- 7 -one （1） regioseleetively via catalyzed brominaton by proline/NBS, and dehydrobrominate by DBU subsequently, lb was converted to a new compound 3 -ethoxycarbonyl -4, 4a, 8, 8a- tetrahydro- 1, 2 - benzoxazin -7 - one （p - tosyl） hydrazone （lc） successfully by reacted with TsNHNH2 catalyzed by BF3 · Et2O.