[Cl:1][C:2]1[CH:3]=[C:4]([NH:14][CH:15]2[CH2:20][CH2:19][O:18][CH2:17][CH2:16]2)[C:5]([O:12][CH3:13])=[C:6]([CH:11]=1)[C:7]([O:9][CH3:10])=[O:8].[CH:21](=O)[CH3:22].C(O)(=O)C.C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+].C([O-])(O)=O.[Na+]>ClCCCl.O>[Cl:1][C:2]1[CH:3]=[C:4]([N:14]([CH2:21][CH3:22])[CH:15]2[CH2:20][CH2:19][O:18][CH2:17][CH2:16]2)[C:5]([O:12][CH3:13])=[C:6]([CH:11]=1)[C:7]([O:9][CH3:10])=[O:8]To a solution of methyl 5-chloro-2-methoxy-3-[(oxan-4-yl)amino]benzoate (220 mg, 0.73 mmol) in 1,2-dichloroethane (2 ml) at room temperature under nitrogen was added acetaldehyde (82 μl, 1.47 mmol) followed by acetic acid (0.25 ml, 4.4 mmol). This solution was stirred for 5 minutes before the addition of sodium triacetoxyborohydride (0.47 g, 2.2 mmol) at room temperature. After stirring for 16 hours acetaldehyde (82 μl, 1.47 mmol) was added to the reaction mixture and stirred for 5 minutes before the addition of sodium triacetoxyborohydride (0.47 g, 2.2 mmol). After stirring for 24 hours, a further acetaldehyde (82 μl, 1.47 mmol) was added to the reaction mixture and stirred for 5 minutes before the addition of sodium triacetoxyborohydride (0.47 g, 2.2 mmol). The reaction was stirred for 24 h after which deionized water (10 ml) was added and the mixture was neutralized with solid NaHCO3. The phases were separated and the aqueous layer was extracted with EtOAc (2×10 ml). The combined organic extracts were dried over MgSO4, filtered and concentrated under reduced pressure. The residue was purified by FCC (10 g silica, Isolute cartridge, gradient of eluents; 95:5 Heptane:EtOAc to 7:3 Heptane:EtOAc) to give 127 mg (53%) of the title compound as a yellow oil. LC-MS 93%, m/z=328.4/330.0, 1H NMR (500 MHz, Chloroform-d) δ ppm 7.35 (d, J=2.6 Hz, 1H), 7.09 (d, J=2.6 Hz, 1H), 3.98 (dd, J=11.3, 4.2 Hz, 2H), 3.91 (s, 3H), 3.85 (s, 3H), 3.48 (tt, J=11.6, 4.0 Hz, 1H), 3.36 (td, J=11.8, 1.9 Hz, 2H), 3.15 (q, J=7.0 Hz, 2H), 1.78 (qd, J=12.2, 4.6 Hz, 2H), 1.72-1.59 (m, 2H), 0.99 (t, J=7.0 Hz, 3H).
Loading…
