Ethyl orthoformate → ethyl 4-methyl-2-(5-oxo-1H-1,2,4-triazol-4(5H)-yl)thiazole-5-carboxylate

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Reaction Conditions

Reaction Steps

To a 2-neck round bottom flask (1 L) equipped with a mechanical stirrer was added ethyl 2-(hydrazinecarboxamido)-4-methylthiazole-5-carboxylate (42.00 g, 172.00 mmol) in anhydrous triethyl orthoformate (393 mL). The yellow reaction mixture was heated at 95° C. for 2 h, and then cooled to ambient temperature. The precipitate was filtered and washed with cold methanol (100 mL) to afford the title compound as a colourless solid (34.9 g, 80%): mp 165-167° C.; 1H NMR (300 MHz, DMSO-d6) δ 12.94 (br, 1H), 9.09 (s, 1H), 4.64 (t, J=7.1 Hz, 2H), 2.98 (s, 3H), 1.67 (t, J=7.1 Hz, 3H); 13C NMR (75 MHz, DMSO-d6) δ 162.3, 157.1, 154.5, 152.3, 133.6, 118.4, 61.9, 17.7, 14.9; MS (ES+) m/z 255.0 (M+1).

Provenance & Evidence