A mechanical stirrer, thermometer and constant pressure dropping funnel were assembled in a 10 L glass reactor and 1 mole of phosphorus pentasulfide (P4S10) and 6 kg of ethylene glycol dimethyl ether were added as solvent under nitrogen protection. Under stirring conditions, 5 moles of formamide was slowly added dropwise and the reaction lasted for 2 hours. Subsequently, 5 moles of ethyl 2-chloroacetoacetate was added dropwise and the reaction was carried out at room temperature for 608 hours. Upon completion of the reaction, the reaction mixture was cooled to 10 °C and the white solid product was collected by filtration. The solid product was dissolved in 4 times its weight in water and the pH was adjusted to 7-8 with 20% sodium hydroxide solution. filtration at 0-5 °C gave ethyl 4-methylthiazole-5-carboxylate as a white solid with 99% purity and 95.8% molar yield.
