Ethyl 2-chloroacetoacetate → Ethyl 2-(4-methoxyphenyl)-4-methyl-1,3-thiazole-5-carboxylate

Participants

Reaction Steps

To a solution of p-methoxythiobenzamide (3 g, 17.95 mmol) dissolved in dry ethanol (180 ml) was added ethyl 2-chloroacetoacetate (1.28 ml, 8.98 mmol), and the mixture was heated under reflux for 1.5 hours. After the reaction was completed, the solvent was distilled off from the reaction mixture. Then the residue was treated with water, made weak alkali (pH=8) with saturated aqueous sodium carbonates, and extracted with ethyl acetate. The organic phase was washed with saturated saline and dried over anhydrous sodium sulfate. After removing the solvent by distillation, the residue was dissolved in chloroform (insoluble solids being filtered off) and applied on silica gel column (developing solvent:n-hexane:ethyl acetate=85:15). After discarding the first fraction (impurities), the second colorless fraction was pooled and concentrated to give 1.9 g of ethyl 2-(4-methoxyphenyl)-4-methyl-5-thiazolecarboxylate as white crystals.

Provenance & Evidence