反应详情

To a solution of 6-chloro-2-trifluoromethyl-2H-1-benzopyran-3-carboxylic acid (Example 1, Step 2)(12.00 g, 43.07 mmol) and (S)(−)-α-methylbenzylamine (2.61 g, 21.54 mmol) in methyl-tert-butyl ether (30 mL) was slowly added n-heptane (200 mL) until the mixture became cloudy. The mixture was heated (steam bath) to boiling and set aside for 24 h during which time crystals formed. Filtration of the suspension yielded a crystalline product (5.5 g) which was recrystallized from methyl-tert-butyl ether (30 mL) and n-heptane (200 mL) yielding upon filtration a white solid (3.1 g). This solid was dissolved in EtOAc (100 mL) and washed with 1 N hydrochloric acid (50 mL) and brine (2×50 mL), dried over MgSO4 and concentrated in vacuo yielding a white solid. Recrystallization of this solid from methyl-t-butyl ether/n-heptane yielded the title compound as the highly enriched isomer, a white solid (2.7 g, 45%): mp 126.7-128.9 ° C. 1H NMR (CDCl3/300 MHz) 7.78 (s, 1H), 7.3-7.1 (m, 3H), 6.94 (d, 1H, J=8.7 Hz), 5.66 (q, 1H, J=6.9 Hz). Anal. Calc'd for C11H6O3F3Cl: C, 47.42; H, 2.17; N, 0.0. Found: C, 47.53; H, 2.14; N, 0.0. This compound was determined to have an optical purity of greater than 90% ee.

1. temperatureThe mixture was heated (steam bath)
2. customformed
3. filtrationFiltration of the suspension