Cholesterol → HCID 86607619, compound

Participants

Reaction Steps

Compound 4 (see FIG. 12) was prepared from galactose 1 that was treated with pivaloyl chloride in pyridine. Instead of the expected penta-pivaloyl derivative, the partially pivaloylated compound 2 was obtained in good yield and high purity without the need of chromatographic purification. The free hydroxyl group in compound 2 was protected by an acetyl group (→3). This was followed by treatment with hydrogen bromide in acetic acid to provide the galactosyl bromide 4. Bromide 4 was coupled with cholesterol 5 under promotion by silver trifluoromethanesulfonate in dichloromethane to provide the desired β-galactosyl-cholesterol 6 in a stereoselective manner (see FIG. 13). The β-anomeric configuration was demonstrated by 1-H NMR spectroscopy. The O-protecting groups were subsequently removed by treatment with sodium methoxide in a mixture of anhydrous dichloromethane and methanol to provide the cholesteryl β-D-galactopyranoside 7 as an amorphous solid.

Provenance & Evidence