Acetonitrile → Isohexane ethyl acetate

Participants

Reaction Steps

Compound 25] and 6-azidohexanol (0.017-0.44 g, 0.12-3.1 mmol) are dissolved in dry acetonitrile and, at 0° C., 4 Å molecular sieves (0.06-1.5 g) and trimethylsilyl trifluoromethanesulfonate (0.001-1.4 g, 0.005-5.1 mmol) are added. After the reaction is complete, the mixture is filtered and washed with saturated sodium bicarbonate solution. Concentration results in the crude product which is purified by chromatography on silica gel with an ethyl acetate/isohexane gradient (0.021-0.51 g, 0.01-0.27 mmol, about 55% yield). It is subsequently taken up in methanol/hydrazine hydrate (1:1) (1-30 ml) and heated at 80° C. until reaction is complete. After evaporation of the solvent, the crude product is taken up in dichloromethane/methanol (1:1) and stirred at 0° C. with acetic anhydride (0.03-4.1 mmol) until the reaction is complete. Evaporation is followed by reduction of the azide with hydrogen in the presence of catalytic amounts of palladium on carbon (10%) (0.001-0.15 g) in methanol (1-45 ml). The crude product compound [26] obtained after evaporation is purified by gel chromatography on Biogel P2 (0.0064-0.17 g, 0.007-0.18 mmol, about 65% yield). FAB-MS: M+H+ =920. 1H-NMR [300 MHz, D2O]: 4.92 (Fuc-H-1), 4.36 (GlcNAc-H-1), 4.28 (Gal-H-1), 4.1-3.35 (m), 3.29 (CH2 --NH3+OAc-), 2.19 (NANA-H-3eq.), 1.93 (NANA-NCOCH3), 1.81 (GlcNCOCH3), 1.77 (NANA-H-3ax.), 1.58-1.18 (O--(CH2)5 --CH2 --NH3+OAc-), 0.99 (Fuc-CH3) ppm.

Provenance & Evidence