反应详情

A stirred solution of 4a (824 mg, 3.13 mmol) in THF (5 mL)/MeOH (5 mL) was treated with 2N LiOH (4 mL), the resultant mixture was stirred at ambient temperature under nitrogen for 30 min. The mixture was treated with 5N HCl (2 mL), followed by adding EtOAc (50 mL) and solid NaCl to saturate the aq. layer. The organic layer was separated, washed with brine (20 mL×2), dried over MgSO4, filtered, and concentrated in vacuo to give a solid residue. After recrystallization from acetone/hexane, 5a (730 mg, 99%) was obtained as a white solid. mp 173.0°-174.0° C.; IR (KBr) 3250-2400 (br), 3108, 1696, 1223 cm-1 ; 1H NMR (DMSO-d6) δ3.76 (2H, s, CH2), 6.89 (1H, t, J=7.8 Hz, Ar), 6.96 (1H, d, J=7.8 Hz, Ar), 7.26 (1H, t, J=7.8 Hz, Ar), 7.45 (1H, s), 7.92 (1H, d, J=7.8 Hz, Ar), 11.33 (1H, s, OH), 12.42 (1H, br s, CO2H); FABMS m/z 235 (M+), 236 (M+ +1); Anal. Calcd for C11H9NO3S: C, 56.16; H, 3.86; N, 5.95. Found: C, 56.30; H, 3.85; N, 6.10.

1. concentrationto saturate the aq. layer
2. customThe organic layer was separated
3. washwashed with brine (20 mL×2)
4. dry with materialdried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customto give a solid residue
8. customAfter recrystallization from acetone/hexane