The present invention provides an improved processes having practical utility for preparing 2-oxindoles of formula I comprising preparation of 2-nitroarylmalonate diester of formula II as first intermediate and subsequent insitu reductive cyclisation using metal acid combination and its modified work-up to form compound of formula I free from metal generated impurity of formula M(OH)X wherein M is metal cation and X is anion. R is selected from hydrogen, linear, branched or cyclic alkyl, aryl, substituted aryl, heteroaryl, haloalkyl like CF3, alkoxy, haloalkoxy, thioalkyl and halogen preferably chloro Formula I wherein R' and R" are same or different and is selected from linear.branched and cyclic alkyl (C1C4groups)preferably methyl R is selected from hydrogen, linear, branched or cyclic alkyl, aryl, substituted aryl, heteroaryl, haloalkyl like CF3, alkoxy, haloalkoxy, thioalkyl and halogen preferably chloro Formula II.
本发明提供了一种改进的工艺,具有实用性,用于制备式I的2-噁嗪,包括制备式II的2-硝基芳基
丙二酸二
酯作为第一
中间体,并随后使用
金属酸组合物进行原位还原环化反应,以及经过改进的工作流程,形成不含
金属生成
杂质M(OH)X的式I化合物,其中M是
金属阳离子,X是阴离子。R从
氢、线性、支链或
环烷基、芳基、取代芳基、杂
环烷基、卤代烷基如
CF3、烷
氧基、卤代烷
氧基、
硫代烷基和卤素中选择,优选
氯代。式I中R'和R"相同或不同,从线性、支链和
环烷基(C1-C4基团)中选择,优选
甲基。R从
氢、线性、支链或
环烷基、芳基、取代芳基、杂
环烷基、卤代烷基如 、烷
氧基、卤代烷
氧基、
硫代烷基和卤素中选择,优选
氯代。式II。