Sulfuric Acid → 1,2,3,4-Tetra-O-benzoyl-alpha-D-mannopyranose

Participants

Reaction Steps

6-O-Trityl-1,2,3,4-tetra-O-benzoyl-α-D-mannopyranose (5 g, 6.0 mmol), was dissolved in MeOH. H2SO4 (conc.) (150 μL) was carefully added, and the solution was stirred at room temperature overnight. The solution was poured into ice-water (300 mL) and extracted with EtOAc (80 mL). The organic layer was separated and washed with brine (80 mL), followed by NaHCO3 (sat.). The solution was dried (Na2SO4), filtered and the solvent evaporated. The crude product was purified using column chromatography (SiO2; Hex:EtOAc, 500:50 to 200:200) to yield 1.79 g of the white solid product (50%). 1H NMR (300 MHz, CDCl3) δ: 8.20-8.12 (m, 4H, Ar), 8.02-7.98 (m, 2H, Ar), 7.87-7.84 (m, 2H, Ar), 7.70-7.26 (m, 27H, Ar), 6.63 (d, 1H, J1,2=2.1, H-1), 6.12 (dd, 1H, J3,2=3.3, J3,4=10.2, H-3), 6.02 (dd, 1H, J4,3=10.0, J4,5=10.0, H-4), 5.89 (dd, 1H, J1,2=1.8, J2,3=3.1, H-2), 4.25 (ddd, 1H, H-5), 3.90-3.76 (m, 2H, H-6).

Provenance & Evidence