Synthesis
General procedure for the synthesis of methyl 4-amino-5-thiazolecarboxylate from methyl 4-amino-2-(methylthio)thiazole-5-carboxylate: methyl 4-amino-2-(methylthio)-1,3-thiazole-5-carboxylate (6.74 g, 33 mmol) was mixed with Raney-Nickel (commercially available slurry, ~15 mL, added in 5 portions) in ethanol (200 mL) in a The suspension was hydrogenated and reacted at 45 psi hydrogen pressure for 1 week. Upon completion of the reaction, the catalyst was removed by filtration and washed with ethyl acetate and ethanol. The filtrate was evaporated to give the crude product. Purification of the crude product by fast column chromatography [eluent: ethyl acetate/isohexane (1:4)] afforded methyl 4-amino-5-thiazolecarboxylate as a bright yellow solid (1.23 g, 24% yield). The product was characterized by NMR (400 MHz, CDCl3): δ 8.54 (1H, s), 5.90 (2H, brs), 3.84 (3H, s). The mass spectrum (ES+) showed a m/z of 159 ([M+H]+).
