Hydrochloric Acid → 5-[4-(2-Oxopropoxy)benzyl]thiazolidine-2,4-dione

Participants

Reaction Conditions

Reaction Steps

A mixture comprising 12 g of ethyl 2-chloro-3-[4-(2-oxopropoxy)phenyl]propionate [prepared as described in step (b) above], 5 g of thiourea and 30 ml of sulfolane was heated at 90° C. for 3 hours, and then 100 ml of ethylene glycol monomethyl ether were added to the mixture, which was then heated for a further 4 hours. At the end of this time, 40 ml of water and 20 ml of concentrated aqueous hydrochloric acid were added to the reaction mixture, and the resulting mixture was heated for 4.5 hours in an oil bath kept at 100° C. After this, the reaction mixture was mixed with water and ethyl acetate, and then the ethyl acetate layer was separated, washed with water and dried over anhydrous sodium sulfate; the solvent was then removed by distillation under reduced pressure. The resulting residue was purified by column chromatography through silica gel, using a gradient elution method, with mixtures of hexane and ethyl acetate ranging from 3:2 to 2:3 by volume as the eluent, followed by crystallization from a mixture of ethyl acetate and hexane, to give 4.2 g of the title compound as crystals, melting at 158°-159° C.

Provenance & Evidence