反应详情

866 mg (3.57 mmol) of (R)-4-ethyl-1-[4-(trifluoromethyl)phenyl]-2-azetidinone produced in Example 6 and 402 mg (5.4 mmol) of methyl carbamate were dissolved in tetrahydrofuran (15 mL) and further mixed with a lithium tert-butoxide/tetrahydrofuran solution (1 mol/L, 5.4 mL, 5.4 mmol) at room temperature. After stirring at the same temperature for 2 hours, water (5.0 mL) was further added to the reaction solution and extraction with toluene (10 mL) was repeated twice. The residue obtained by concentration of the separated organic layer after washing with water was purified on silica gel column chromatography to obtain methyl (R)-{3-[4-(trifluoromethyl)phenylamino]-pentanoyl}carbamate as a white solid (897 mg, isolated yield: 79%). 1H-NMR (CDCl3, 400 MHz/ppm): 5 0.98 (3H, t), 1.5-1.8 (2H, m), 2.9-3.2 (2H, m), 3.77 (3H, s), 3.8-3.9 (1H, m), 4.2-4.3 (1H, br), 6.60 (2H, d), 7.37 (2H, d), 7.9-8.1 (1H, br)

1. customThe residue obtained by concentration of the separated organic layer
2. washafter washing with water
3. customwas purified on silica gel column chromatography
4. customto obtain