Lithium hydroxide, monohydrate → 1-(2-Oxo-2,3-dihydro-1,3-benzoxazol-5-YL)cyclopropane-1-carboxylic acid

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Reaction Conditions

Reaction Steps

To a solution of 1-(2-oxo-2,3-dihydro-benzooxazol-5-yl)-cyclopropanecarboxylic acid methyl ester (1.9 g, 8.1 mmol) in MeOH (20 mL) and water (2 mL) was added LiOH.H2O (1.7 g, 41 mmol) in portions at room temperature. The reaction mixture was stirred for 20 hours at 50° C. MeOH was removed by evaporation under vacuum before water (100 mL) and EtOAc (50 mL) were added. The aqueous layer was separated, acidified with HCl (3 mol/L) and extracted with EtOAc (100 mL×3). The combined organic layers were dried over anhydrous Na2SO4 and evaporated under vacuum to give 1-(2-oxo-2,3-dihydrobenzo[d]oxazol-5-yl)cyclopropanecarboxylic acid (1.5 g, 84%). 1H NMR (DMSO, 400 MHz) δ 12.32 (brs, 1 H), 11.59 (brs, 1 H), 7.16 (d, J=8.4 Hz, 1 H), 7.00 (d, J=8.0 Hz, 1 H), 1.44-1.41 (m, 2 H), 1.13-1.10 (m, 2 H). MS (ESI) m/e (M+H+) 218.1.

Provenance & Evidence