Synthesis of shikonin-1'-O-β-D-glucopyranoside by the trichloroacetimide ester method

ObjectiveTo synthesize shikonin-1'-O-β-D-glucopyranoside by the trichloroacetimide ester method.

MethodsThe glycosyl donor 2, 3, 4, 6-tetra-O-acetyl-β-D-galactopyranoyl-2, 2, 2-trichloroacetyl was prepared from β-D-glucopyranose as starting material.The imine ester was then reacted with shikonin to obtain1-(1-(5, 8-dihydroxy-1, 4-naphthoquinone-2-yl)-4-methyl-3-pentenoxy)-2, 3, 4, 6-tetra-O-acetyl-β-glucopyranoside, and finally alcoholyzed to remove the acetyl group under the sodium methoxide/methanol system to obtain the target compound.The structure of the target compound was elucidated by nuclear magnetic resonance spectroscopy (NMR) and electrospray ionization mass spectrometry (ESI-MS).

ResultsThe target compound was identified as shikonin-1'-O-β-D-glucopyranoside by NMR and ESI-MS.The total yield of shikonin-1'-O-β-D-glucopyranoside synthesized by the trichloroacetimide ester method was 38.9%, and the purity determined by HPLC was 96.7%.

ConclusionsThe method has the advantages of high stereoselectivity and high yield.It can be used for the synthesis of shikonin-1'-O-β-D -glucopyranoside, and provide a reference for the chemical synthesis of shikonin glycosylation modified products.