反应详情

Methoxyl-amine hydrochloride (30-35 wt % in H2O, 0.30 mL, 1.12 mmol) was added in one portion to a solution of 1,5-bis(2-hydroxyphenyl)penta-1,4-dien-3-one (EF1) in methanol/CHCl3 (2/3) (5 mL). The reaction proceeded at room temperature for 24 hrs, then additional methoxylamine hydrochloride (0.15 mL, 0.56 mmol) was added and the reaction stirred for an additional 24 hrs. After completion (TLC) the solvent was evaporated, the residue dissolved in methanol, stirred with silica gel and purified after concentration by chromatography on silica gel using 30% EtOAc/hexanes. The product was obtained as a pale yellow foam (86%). 1H NMR (400 MHz, CDCl3) δ 7.56 (1H, dd, J=8.0 Hz, J=1.6 Hz), 7.48 (1H, dd, J=8.0 Hz, J=1.6 Hz), 7.41 (1H, d, J=16.0 Hz), 7.39 (1H, d, J=16.8 Hz), 7.28 (1H, d, J=16.8 Hz), 7.20-7.13 (2H, m), 6.97-6.90 (2H, m), 6.94 (1H, d, J=16.0 Hz), 6.80 (1H, dd, J=8.0 Hz, J=1.6 Hz), 5.53 (1H, s-br), 5.36 (1H, s-br), 4.02 (3H, s). 13C NMR (100 MHz, CDCl3) δ 155.43, 153.86, 153.70, 132.28, 130.25, 130.10, 129.71, 128.00, 127.91, 124.16, 123.88, 123.57, 121.40, 121.30, 118.45, 116.37, 116.33, 62.41.

1. customAfter completion (TLC) the solvent was evaporated
2. dissolutionthe residue dissolved in methanol
3. stirringstirred with silica gel
4. custompurified
5. concentrationafter concentration by chromatography on silica gel using 30% EtOAc/hexanes