Compound 1C (3.3 g, 8.3 mmol) and 4-thiazolecarboxaldehyde (1.4 g, 12.4 mmol) in dichloroethane (16 mL) were stirred for 30 min. under nitrogen. Sodium triacetoxyborohydride (5.3 g, 24 9 mmol) was added and the reaction was stirred for 20 h. The mixture was diluted with CH2Cl2 (20 mL) and washed with saturated aqueous NaHCO3. The organic phase was dried over Na2SO4 and concentrated. Column chromatography (120 g silica gel, eluting with 4% 7N NH3/MeOH in CH2Cl2) gave 2.01 g 1D as a white solid (49%). 1H NMR (500.333 MHz, CDCl3) δ 8.90 (dd, J=4.1, 1.7 Hz, 1H), 8.76 (d, J=1.9 Hz, 1H), 8.11 (dd, J=8.0, 1.5 Hz, 1H), 7.72 (dd, J=7.3, 2.3 Hz, 1H), 7.51-7.46 (m, 2H), 7.37-7.33 (m, 3H), 7.31-7.29 (m, 2H), 7.18 (s, 1H), 3.85 (s, br, 2H), 3.76 (s, 2H), 3.67 (br s, 2H), 3.26 (br s, 1H), 3.02 (s, 3H), 2.78-2.71 (m, 1H), 2.67-2.52 (m, 4H), 2.46-2.37 (m, 1H), 2.14-2.04 (m, 2H). TOF MS E+ 499.21.
