Epipinoresinol → Pinoresinol diglucoside

Beteiligte Stoffe

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Reaktionsschritte

Pinoresinol-diglucoside - Silver oxide (2.24 g, 9.65 mmol) was added to a stirred reaction mixture of pinoresinol (358 mg, 1 mmol) and aceto-α bromo glucose (2.24 g, 5.45 mmol) in 6 ml of dry quinoline over a period of 15 min. After stirring the reaction mixture for 16 hours at 25° C., the reaction mixture was extracted with 20 ml of ether. The organic ethereal layer was successively washed with water (2 × 10 ml), 1 N HCl (5 × 5 ml), dilute NaHCO3 (3 × 5 ml) and dried over Na2SO4. After evaporation of the organic solvent in vacuo, the residue was dissolved in 20 ml of methanol containing 1 ml of 5 N NaOH and the mixture was stirred for 2 hours at 0° C. After acidification to pH 4.5 with 2N HCl, this mixture was evaporated to dryness. The residue was dissolved in 5 ml of water and chromatographed over an Amberlite XAD-2 column (1.9 × 38 cm). The column was washed with 150 ml of water to remove salts. The diglucoside was then eluted off the column with 250 ml of 20% aqueous acetone. The combined acetone fractions were evaporated to dryness and the residue was chromatographed over a silica-gel column (3.5 × 44 cm). Elution of the column with solvent system, CHCl3 :CH3OH:H2O (65:30:10) gave 230 mg (34%) of pure pinoresinol diglucoside, m.p. 238-250°; uv (H2O) 276 nm (ε6,600) and 226 (ε21,900); [α]D25 -15.3° (c, 0.4, H2O); IR (KBr) 1600, 1515, 1414, 1275, 1260, 1230, 1080, 1050, 1030, 993 810 cm-1. Anal calcd for C32H42O16.4H2O: C, 50.92; H, 6.68. Found: C, 50.70; H, 6.70.

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