反应详情

To a mixture of 4-methoxybenzylamine (5.420 g, 39 mmol) and NaOAc.3H2O (29.324 g, 215 mmol) in H2O (25 ml) at 0° C. was added 2N HCl (21.5 ml) followed by acetonedicarboxylic acid (6.559 g, 45 mmol). The reaction was stirred until a clear light brown solution was obtained then the ketoaldehyde (Step 1, 8.267 g, 36 mmol) in THF (25 ml) was added. The reaction was stirred for 30 mins at 0° C. then allowed to warm to rt before heating at 40° C. for 3 hrs. The reaction was allowed to cool and the pH was adjusted to 10 using NaHCO3 and 4N NaOH solution. The mixture was extracted with EtOAc (×3), the combined extracts were washed with brine, dried (MgSO4), filtered and evaporated. The residue was purified by chromatography (silica, 10% EtOAc/isohexane) to give the ketone (3.837 g, 27%). 1H NMR (360 MHz, CDCl3) δ: 1.59-1.66 (1H, m), 2.02-2.21 (4H, m), 2.81-2.87 (3H, m), 3.48 (1H, d, J 13.5), 3.55 (1H, d, J 13.5), 3.65 (1H, t, J 4.9), 3.81 (3H, s), 6.86-6.90 (2H, m), 7.26-7.29 (2H, m), 7.63-7.69 (4H, m).

1. customwas obtained
2. stirringThe reaction was stirred for 30 mins at 0° C.
3. temperaturebefore heating at 40° C. for 3 hrs
4. temperatureto cool
5. extractionThe mixture was extracted with EtOAc (×3)
6. washthe combined extracts were washed with brine
7. dry with materialdried (MgSO4)
8. filtrationfiltered
9. customevaporated
10. customThe residue was purified by chromatography (silica, 10% EtOAc/isohexane)