Triethylamine → 4-chloro-N-(methoxycarbonylmethylthio)acetylanthranilic acid methyl ester

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Reaction Steps

21.24 g (0.114 mol) of 4-chloroanthranilic acid methyl ester and 19.1 ml (0.137 mol) of triethylamine are placed in 180 ml of methylene chloride at 0°. A solution of 20.9 g (0.114 mol) of 2-(chloroformylmethylthio)-acetic acid methyl ester (T. Terasawa and T. Okada, J. Org. Chem., 42, 1163 (1977)) in 20 ml of methylene chloride is added dropwise thereto and the mixture is then stirred for 15 minutes at 0° and for 3 hours at room temperature. The reaction mixture is extracted with water and brine and the aqueous phases are washed with methylene chloride. The organic phases are combined, dried with sodium sulfate, filtered and concentrated. Chromatography of the crude product on silica gel with hexane/ethyl acetate (4:1) yields, in the form of yellowish crystals, 4-chloro-N-(methoxycarbonylmethylthio)acetylanthranilic acid methyl ester which is still impure.

Provenance & Evidence