Lawesson's reagent → Ethyl 5-amino-2-methylthiazole-4-carboxylate

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Reaction Steps

To a solution of acetylamino-cyano-acetic acid ethyl ester (27.2 g, 0.160 mol) in anhydrous toluene (300 mL) was added Lawesson's reagent (32.0 g, 0.079 mol) and the resulting mixture heated at reflux for 18 h. The resulting yellow suspension was partitioned between an aqueous solution of HCl (1 M) and tert-butyl methyl ether. The layers were separated and the organic layer extracted with an aqueous solution of HCl (1 M). The combined aqueous layers was basified to pH 10 with an aqueous solution of NaOH (2 M), then extracted with EtOAc. The organic layer was isolated, dried (Na2SO4) and concentrated in vacuo to give the title compound as a pale yellow solid (17.0 g, 57%).

Provenance & Evidence