反应详情

To a mixture of (−)-cyclopentylmandelic acid, R(−)1, (1.83 g, 8.3 mmol) and potassium carbonate (2.87 g, 21 mmol) in DMF (21 ml), methyl iodide (3.53 g, 25 mmol) was added at room temperature. The mixture was stirred at room temperature for 2 h, and then poured into water and extracted with hexanes three times. Evaporation of the dried hexanes extract gave a crude product. Flash chromatography of the crude product on silica gel with 1.5:1 hexanes:methylene chloride gave pure product R(−)2 (1.95 g, 100%). Analysis for C18H18O3. Calcd: C, 71.77; H, 7.74. Found: C, 71.88; H, 7.80. 1H NMR (CDCl3, 500 MHz): 1.32-1.36, 1.43-1.61 [8H, m, (CH2)4], 2.90 [1H, p, CHC(OH)], 3.71 (1H, s, OH), 3.79 (3H, s, CH3), 7.25-7.28, 7.31-7.35, 7.63-7.65 (5H, m, Ph) ppm.

1. extractionextracted with hexanes three times
2. customEvaporation of the dried hexanes
3. extractionextract
4. customgave a crude product