Oxalic Acid → N-(6-Methyl-3-oxo-2,5-dihydro-1,2,4-triazin-4(3H)-yl)acetamide

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Reaction Steps

To a solution of 5-methyl-3-(2-oxo-propyl)-3H-1,3,4-oxadiazol-2-one (2.052 g, 13.14 mmol) in a mixture of 2-propanol (12 mL) and water (0.3 mL) is added hydrazine monohydrate (0.96 mL, 19.8 mmol). The mixture is stirred at rt under N2 for 15 h, and then heated to reflux for 7 h. A solution of oxalic acid (0.363 g, 4.032 mmol) in 2-propanol (6 mL) is added to the warm reaction solution. The resulting precipitate is removed by filtration through a coarse porosity sintered glass funnel, and the filtrate is concentrated in vacuo to approximately 10 mL in total volume. The concentrated solution is chilled to −12° C., and the resulting crystals are collected by filtration and dried to afford N-(6-methyl-3-oxo-2,5-dihydro-3H-1,2,4-triazin-4-yl)-acetamide (1.562 g, 70%). MS: 171 (M+H); 1H NMR (300 MHz, CDCl3) δ 8.10 (br s, 1H), 7.57 (br s, 1H), 4.20 (s, 2H), 2.04 (s, 3H), 1.95 (s, 3H); 1H NMR (300 MHz, DMSO-d6) δ 9.98 (s, 1), 9.74 (s, 1), 4.04 (s, 2), 1.84 (s, 6).

Provenance & Evidence