Scheme 5.
Synthesis of methyl 2,3-di-O-galloyl-α-d-glucopyranoside 7 from 14 (in total 64.5% yield of 7 from 22).
Reagents and conditions: (a) BnG-Cl, in anhydrous pyridine, 60 °C, 48 h; (b) H2, 10% Pa-C, in THF containing approximate 13% of aqueous 95% EtOH, 40 °C, 10 atm, 12 h; (c) 1 N HCl, 55 °C, 6 h.