Hydrochloric Acid → methyl 2-oxo-2,3-dihydro-1H-1,3-benzodiazole-5-carboxylate

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Reaction Conditions

Reaction Steps

To a solution of 3,4-diamino-benzoic acid methyl ester (5.00 g, 30.1 mmol) and THF (40 mL), was added carbonyl diimidazole (7.32 g, 45.1 mmol) at 0° C. The mixture stirred for 16 h, and allowed to warm to 23° C. A solution of 1M aq. HCl (50 mL) was added at 0° C., followed by water (70 mL) and the mixture was stirred for 1 h. The resulting precipitate was filtered and dried under reduced pressure for 18 h to yield the titled compound, which was used in the next step without further purification (5.45 g, 94%). MS (ESI/CI): mass calcd. for C9H8N2O3, 192.1; m/z found, 193.1 [M+H]+. 1H NMR (400 MHz, CDCl3): 11.01 (s, 1H), 10.84 (s, 1H), 7.63 (dd, J=8.2, 1.6 Hz, 1H), 7.47 (s, 1H), 7.02 (d, J=8.2 Hz, 1H), 3.82 (s, 3H).

Provenance & Evidence