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[摘要]:An efficient one-pot procedure for the preparation of 2-(1,4-dihydro-2H-3,1-benzothiazin-2-ylidene)propanedioic acid derivatives from 2-(1-bromoalkyl)phenyl isothiocyanates with propanedioic (malonic) acid derivatives, such as propanedinitrile, ethyl cyanoacetates, 3-oxo-3-(pyrrolidin-1-yl)propanenitrile and diethyl propanedioate, has been developed. The reactions are carried out in the presence of two equivalents of sodium hydride at -20 degrees C to give the desired products. |
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