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Process for the preparation of 1H-pyrrole-2-acetic esters
Process for the preparation of 1H-pyrrole-2-acetic esters
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机译:1H-吡咯-2-乙酸酯的制备方法
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摘要
A process for the preparation of esters of 1H-pyrrol-2-acetic acids of the formula IMAGE I wherein R1 is selected from the group consisting of hydrogen and alkyl of 1 to 4 carbon atoms and R2 is selected from the group consisting of alkyl of 1 to 4 carbon atoms and aralkyl of 1 to 4 alkyl carbon atoms comprising reacting a compound of the formula IMAGE II wherein R3 is selected from the group consisting of -CN and IMAGE in an aqueous media with a saponification base wherein the saponification base is added gradually to the 1H-pyrrol-2-acetonitrile and/or 1H-pyrrol-2-acetamide to selectively saponify the same to obtain a substantially isomer-free salt of 1H-pyrrol-2-acetic acid, adding alkali metal bicarbonate to the solution to keep the pH of solution at about 10.2 to 10.5 and reacting the salt of 1H-pyrrol-2-acetic acid without isolation and without removal of any water with a solution of an alkylating or aralkylating agent in an organic water-insoluble solvent in the presence of a phase transfer agent to obtain the ester of formula I in excellent yields and purity.
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