反应详情

To a suspension of anhydrous tin (II) chloride (2.5 g, 13.2 mmol) in 150 mL of methylene chloride was added ethyl diazoacetate (8.3 g, 72.8 mmol). Then 3-nitrobenzaldehyde (10.0 g, 66.2 mmol) was added as a solid in small portions over 30 min. The resulting suspension was stirred at room temperature for 24 h. Additional tin (II) chloride (2.5 g) was added and the reaction was stirred an additional 24 h. The reaction was concentrated in vacuo, diluted with ethyl acetate, washed with water (2 times) and brine, dried (MgSO4) and concentrated. The residue was purified by flash chromatography (elution with 4:1 hexanes/ethyl acetate) to afford 5 g (32%) of the title compound. 1H NMR (CDCl3) (approximately 12:1 mixture of enol and keto tautomers, data for enol only) δ: 12.6 (s, 1H); 8.60 (t, 1H, J=1.8 Hz); 8.3 (m, 1H); 8.1 (m, 1H); 7.62 (t, 1H, J=7.9 Hz) 5.77 (s, 1H); 4.30 (q, 2H, J=7.2 Hz); 1.35 (t, 3H, J=7.2 Hz).

1. stirringthe reaction was stirred an additional 24 h
2. concentrationThe reaction was concentrated in vacuo
3. additiondiluted with ethyl acetate
4. washwashed with water (2 times) and brine
5. dry with materialdried (MgSO4)
6. concentrationconcentrated
7. customThe residue was purified by flash chromatography (elution with 4:1 hexanes/ethyl acetate)