反应详情

To a solution containing the compound 18 (0.502 g, 0.972 mmol) in ethanol (10 mL) was slowly added concentrated hydrochloric acid (12N, 2 mL). The clear solution was stirred at room temperature for 4 hours. The reaction mixture was concentrated under vacuum. The residue was taken into ethanol (3 mL) and the resulting solution was concentrated again under vacuum. The procedure was repeated two more times to ensure no aqueous solvent remained. The residue was chromatographed over silica gel, eluting with a mixture of concentrated ammonium hydroxide (0-10%), methane (0-30%), and methylene chloride (100-60%), to afford 0.396 g (98%) of the product 19 as a low melting white solid. [α]D25=+24.2° (c 0.265, MeOH). 1H NMR (300 MHz, DMSO-d6): δ 1.32-1.52 (m, 4H), 2.46-2.55 (m, 4H), 2.74-2.79 (m, 2H), 2.84-2.96 (m, 2H), 3.31-3.99 (m, 16H), 4.01 (t, J=5.9 Hz, 2H), 6.40 (br s, 2H), 6.82 (d, J=8.5 Hz, 2H), 7.09 (d, J=8.5 Hz, 2H). m/z (APCI)=417 [C20H36N2O7+H]+.

1. concentrationThe reaction mixture was concentrated under vacuum
2. concentrationthe resulting solution was concentrated again under vacuum
3. customThe residue was chromatographed over silica gel
4. washeluting with a mixture of concentrated ammonium hydroxide (0-10%), methane (0-30%), and methylene chloride (100-60%)