Trimethyl orthoformate → 1-Benzooxazol-5-yl-cyclopropanecarboxylic acid methyl ester

Participants

Reaction Steps

To a solution of 1-(3-amino-4-hydroxy-phenyl)-cyclopropanecarboxylic acid methyl ester (3.00 g, 14.5 mmol) in DMF were added trimethyl orthoformate (5.30 g, 14.5 mmol) and a catalytic amount of p-tolueneslufonic acid monohydrate (0.3 g) at room temperature. The mixture was stirred for 3 hours at room temperature. The mixture was diluted with water and extracted with EtOAc (100 mL×3). The combined organic layers were dried over anhydrous Na2SO4 and evaporated under vacuum to give crude 1-benzooxazol-5-yl-cyclopropanecarboxylic acid methyl ester (3.1 g), which was directly used in the next step. 1H NMR (CDCl3, 400 MHz) δ 8.09 (s, 1), 7.75 (d, J=1.2 Hz, 1 H), 7.53-7.51 (m, 1 H), 7.42-7.40 (m, 1 H), 3.66 (s, 3 H), 1.69-1.67 (m, 2 H), 1.27-1.24 (m, 2 H).

Provenance & Evidence