反応 #67415

反応方程式

p-toluenesulfonic acid monohydrate

1-(3-amino-4-hydroxy-phenyl)-cyclopropanecarboxylic acid methyl ester

trimethyl orthoformate

→

1-benzooxazol-5-yl-cyclopropanecarboxylic acid methyl ester

収率 98.4%

溶媒

water

DMF

反応条件

後処理

1. 1
   その他at room temperature
2. 2
   抽出extracted with EtOAc (100 mL×3)
3. 3
   乾燥The combined organic layers were dried over anhydrous Na2SO4
4. 4
   その他evaporated under vacuum

実験手順

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-toluenesulfonic 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, 1H), 7.53-7.51 (m, 1H), 7.42-7.40 (m, 1H), 3.66 (s, 3H), 1.69-1.67 (m, 2H), 1.27-1.24 (m, 2H).

出典