Acetic Anhydride → 5-[1-(2-Acetylaminothiazol-4-yl)-1-ethoxycarbonylmethylene]-2,4-dioxothiazolidine-3-acetic acid

Beteiligte Stoffe

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Reaktionsschritte

A mixture comprising 0.6 g of crude 5-{1-ethoxycarbonyl-1-hydroxy-1-[2-(3-phenylureido)thiazol-4-yl]methyl}-2,4-dioxothiazolidine-3-acetic acid [prepared from 2.6 g of ethyl 2-(3-phenylureido)thiazol-4-ylglyoxylate, 1.2 g of 2,4-dioxothiazolidine-3-acetic acid, 1.2 g of piperidine and 30 ml of ethanol by a procedure similar to that of Example 24], 0.5 g of acetic anhydride and 4 ml of pyridine was heated at 60° C. for 17 hours. The reaction mixture was poured into water and extracted with ethyl acetate. The extract was dried over anhydrous sodium sulfate, and the solvent was evaporated off under reduced pressure. The resulting oil was purified by silica gel column chromatography, using as eluent a 8:2:0.5 to 7:3:0.5 by volume mixture of benzene ethyl acetate and acetic acid, giving the desired compound as a yellow powder having the following physical properties.

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