Facile synthesis of 2-substituted ethyl 2-(2-amino-5-ethoxy-carbonylthiazol-4-yl)ethanoates

An easy and convenient synthesis of highly functionalized 2-aminothiazole derivatives is described. Ethyl 2-bromo-2-(2- amino-5-ethoxycarbonylthiazol-4-yl) ethanoate 4 was obtained by reaction of 2,4-dibromo-3-oxoglutarate with thiourea. It can be transformed to 2-iminoethanoate 10 by nucleophilic displacement of the bromide with an azide ion followed by rearrangement with elimination of the molecule of nitrogen. Hydrolysis of the iminoethanoate 10 affords 2-oxoethanoate 12, while hydrogenation leads to 2-aminoethanoate 14. The crystal structure determination of 2-iminoethanoate 11 is reported.