Cesium carbonate → HCID 57414008, compound

Participants

Reaction Conditions

Reaction Steps

Under nitrogen atmosphere, the mixture of [(2R,3S,4S,5R,6R)-4,5-diacetoxy-6-(acetoxymethyl)-2-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenoxy]tetrahydropyran-3-yl]acetate (0.132 g, 0.24 mmol), methyl 5-bromonicotinate (0.043 g, 0.2 mmol), cesium carbonate (0.196 g, 0.6 mmol) and tetrakis(triphenylphosphine)palladium (0.023 g, 0.02 mmol) in dioxane/water (5 mL/1 mL) was heated at 80° C. with stirring for 1 h. After cooling down, the mixture was filtered through silica gel column to remove the metal catalyst and salts with hexane/ethyl acetate (2/1) containing 2% triethylamine as eluent. The filtrate was concentrated, then dried in vacuo. Into the residue, 6 mL of methanol with catalytic amount of sodium methoxide (0.02 M) was added and the mixture was stirred at room temperature overnight. The solvent was removed. The resulting residue was purified by silica gel chromography with CH2Cl2/MeOH combinations containing 2% NH3/H2O as eluent, giving rise to 12b (0.031 g) in 40% yield. 1H NMR (300 MHz, CD3OD) δ ppm 3.53-3.65 (m, 1H) 3.67-3.83 (m, 3H) 3.89-3.96 (m, 1H) 3.99 (s, 3H) 4.04 (dd, J=3.43, 1.79 Hz, 1H) 5.57 (d, J=1.92 Hz, 1H) 7.22-7.37 (m, 2H) 7.58-7.73 (m, 2H) 8.54 (t, J=2.06 Hz, 1H) 8.97 (d, J=2.20 Hz, 1H) 9.04 (d, J=1.92 Hz, 1H). MS (ESI): found: [M+H]+, 392.1.

Provenance & Evidence