Reaction Steps
To a stirred solution of methyl 4-[[1-[3-methoxy-4-[N′-(2-methyl phenyl)ureido]phenylacetyl]-2-pyrrolidinyl]methylthio]benzoate (264 mg, 0.482 mmol) in CH2Cl2 (5.2 mL) was added m-CPBA (118.8 mg, 0.482 mmol) at 0° C., and the mixture was stirred at room temp for 1 hr. The mixture was diluted with CHCl3, and quenched with sat. Na2S2O3. The separated organic layer was washed with sat. NaHCO3, brine, and dried over Na2SO4. The solvent was removed under a reduced pressure to afford methyl 4-[[1-[3-methoxy-4-[N′-(2-methylphenyl)ureido]phenylacetyl]-2-pyrrolidinyl]methylsulfinyl]benzoate as a crude amorphous solid. To a stirred solution of this crude compound in THF. (4 mL) and H2O (1 mL) was added LiOH (34.6 mg, 1.45 mmol), and the stirring was continued overnight at room temp. The mixture was diluted with CHCl3, washed with 1N HCl, brine, and dried over Na2SO4. The solvent was removed under a reduced pressure, and the obtained crude solid was recrystallized from n-hexane-CHCl3—MeOH to afford 193.2 mg (73%) 24 as a white crystalline powder. IR (KBr) 3338, 2956, 1708, 1529, 1299, 1207, 1155 cm−1; 1H-NMR (400 MHz, DMSO-d6) δ1.70-2.06 (m, 4H), 2.24 (s, 3H), 2.90 (dd, J=8.3, 13.2 Hz, 1H), 3.02-3.08 (m, 1H), 3.16-3.25 (m, 1H), 3.41-3.60 (m, 3H), (s, 3H), 4.40 (br s, 1H), 6.74 (d, J=7.8 Hz, 1H), 6.87 (s, 1H), 6.94 (d, J=7.3 Hz, 1H), 7.11-7.17 (m, 2H), 7.75-7.81 (m, 3H), 7.98-8.05 (m, 1H), 8.10 (d, J=8.3 Hz, 2H), 8.46 (s, 1H), 8.56 (s, 1H); MS (FAB) m/z 550 (M++1), 572 (M++Na); Anal. Calcd. for C29H31N3O6S.3/2H2O: C, 60.40; H, 5.94; N, 7.29. Found: C, 60.15; H, 5.82; N, 6.90.
