Potassium Carbonate → (6-Benzoylamino-hexyl)-{2-[4-(3,4,5-trihydroxy-6-hydroxymethyl-tetrahydro-pyran-2-yloxy)-phenylcarbamoyl]-ethyl}-carbamic acid tert-butyl ester

関与物質

反応手順

Compound 4 (0.88 g, 2.7 mmol) and 6 (0.71 g, 3.2 mmol) in a solution of isopropanol (30 ml) and H2O (4 ml) is stirred at 65° C. (oil bath) in a capped 100 ml RBF for 48 hrs. TLC on silica shows that at least 85% of 4 is converted to the Michael addition product (Rf=0, 30:1 acetone-concentrated ammonium hydroxide). The reaction is allowed to cool to ambient temperature, followed by the addition of powdered K2CO3 (0.44 g, 3.2 mmol) and di-tert-butylcarbonate (0.84 mg, 3.8 mmol, Aldrich). The mixture is stirred at ambient temperature for 3 hr. TLC should show at least 80% of Michael addition product was converted to the desired product (Rf=0.17, 10:1 acetone-concentrated ammonium hydroxide). The solid is collected by vacuum filtration and is washed with 30 ml of MeOH. The filtrates are combined, and solvent is removed by rotary evaporation to give an oily residue. MeOH (6.5 ml) is added to dissolve the residue, and the pH is adjusted to ˜3-4 (moist pH paper) by addition of trifluoroacetic acid with chilling on ice. The desired product is purified by 10 runs of preparative HPLC: 50% MeOH in H2O, at a flow rate of 6 ml/min; tR=27 min. Product fractions are pooled, and most of the solvent is removed by rotary evaporation at ambient temperature. The remaining solvent is removed by lyophilization, and the resulting residue is dissolved in 20 ml of MeOH. Solvent is removed by rotary evaporation, and the oily residue is dried in vacuum to give a white solid (1.1 g, 63%). ESI-MS (M+H)+: 646.6; 1H-NMR (1:2.5 D2O/acetone-d6) δ 7.80˜7.75 (2H, m, COCCH), 7.55˜7.35 (5H, m, COCHCHCH and NHCCH), 7.05 (2H, d, J=9.0 Hz, NHCCHCH), 5.39 (1H, d, J=3.4 Hz, H-1), 4.00˜3.57 (6H, m, H-2,3,4,5,6,6′), 3.51 (2H, t, J=6.8 Hz, COCH2CH2), 3.30 (2H, t, J=7.0 Hz, CONHCH2), 3.16 (2H, t, J=7.0 Hz, CONH(CH2)5CH2), 2.55 (2H, t, J=6.4 Hz, COCH2), 1.70-1.20 (17H, m, O-tert-C4H9 and NHCH2(CH2)4).

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