反应详情

To a cooled solution of methyl 2-acetylamino-4-aminobenzoate (300 mg, 1.44 mmol) and N-tert-butoxycarbonyl-N-methylglycinal (499 mg, 2.88 mmol) in 1,2dichloroethane (30 ml), was added NaBH(OAc)3 (964 mg, 4.32 mmol) and the stirring was continued for 64 h at 0° C. The mixture was poured into sat. NaHCO3 and was extracted with CHCl3 (50 ml×3), washed with brine, and dried over MgSO4. After removal of the solvent in vacuo, the residue was chromatographed on silica gel (middle pressure chromatography system: YAMAZEN YFLC-5404-FC, linear gradient of hexane-EtOAc from 9:1 to 2:1) to give methyl 2-acetylamino-4-[2-(N-tert-butoxycarbonyl-N-methylamino)ethylamino]benzoate (451 mg, 86%) as a colorless oil. 1H-NMR (CDCl3, 400 MHz) δ1.48 (s, 9 H), 2.22 (s, 3 H), 2.90 (s, 3 H), 3.32 (m, 2 H), 3.50 (m, 2 H), 3.80 (s, 3 H), 6.20 (dd, J=2.2 Hz, 8.8 Hz, 1H), 7.80 (m, 1H, 7.95 (m, 1H), 11.30 (brs, 1 H); MS (FAB) m/z 366 (M++1).

1. extractionwas extracted with CHCl3 (50 ml×3)
2. washwashed with brine
3. dry with materialdried over MgSO4
4. customAfter removal of the solvent in vacuo
5. customthe residue was chromatographed on silica gel (middle pressure chromatography system: YAMAZEN YFLC-5404-FC, linear gradient of hexane-EtOAc from 9:1 to 2:1)