反应详情

A suspension of ester 26 (1.00 g, 3.16 mmol) in MeOH (8 mL) was treated with a solution of NaOH (155 mg, 3.88 mmol) in water (4 mL) and heated at reflux for 3.5 h. After cooling to room temperature, the solution was adjusted to pH 6 with 2 M HCl and the solvent was removed under reduced pressure. The residue was dissolved in MeOH, 2 M HCl was added dropwise, and the formed precipitate was collected by filtration to give 27 (712 mg, 69%) as a brown solid. The residue obtained after evaporation of the mother liquor was purified by column chromatography (CH2Cl2/MeOH, 6:1, 1% cone. HCl) to provide a second batch of 27 (226 mg, 22%). 1H NMR (300 MHz, DMSO-d6): δ=1.56-1.77 (m, 2 H, 3′-Hax, 5′-Hax), 1.89-2.09 (m, 3 H, 3′-Heq, 41-H, 5′-Heq), 2.69 (s, 3 H, NMe), 2.87-3.05 (m, 2 H, 2′-Hax, 6′-Hax) 3.24-3.48 (m, 2 H, 2′-Heq, 6′-Heq), 3.79-3.92 (m, 2 H, ArOCH9), 6.90 (dd, J=9.0, 2.2 Hz, 1 H, 6-H), 6.98 (d, J=1.7 Hz, 1 H, 3-H), 7.12 (d, J=2.2 Hz, 1 H, 4-H), 7.34 (d, J=9.0 Hz, 1 H, 7-H), 10.84 (sbr, 1H, NH+), 11.59 (s, 1H, NH), 12.74 (sbr, 1 H, CO2H) ppm. —13C NMR (75.5 MHz, DMSO-d6): δ=25.8 (C-3′, C-5′), 32.8 (C-4′), 42.5 (NMe), 52.8 (C-2′, C-6′), 71.6 (OCH2), 103.4 (C-4), 106.8 (C-3), 113.3 (C-7), 116.0 (C-6), 127.1 (C-2), 128.7 (C-3a), 132.6 (C-7a), 152.9 (C-5), 162.5 (C═O) ppm. −MS (70 eV, EI): m/z (%)=288 (14) [M−HCl]+, 112 (100) [C7H14N]+. —C16H21ClN2O3 (324.80): calcd. 288.1474 [M−HCl]+; found 288.1474.

1. temperatureheated
2. temperatureat reflux for 3.5 h
3. customthe solvent was removed under reduced pressure
4. dissolutionThe residue was dissolved in MeOH
5. addition2 M HCl was added dropwise
6. filtrationthe formed precipitate was collected by filtration