反应详情

A solution of benzyl 3-formyl-2-methylphenylcarbamate (5.1667 g, 19.19 mmol), nitroethane (6.89 ml, 96 mmol) and ammonium acetate (7.39 g, 96 mmol) in acetic acid (Volume: 64.0 ml) under nitrogen was heated at 95° C. After 3 h, the reaction was cooled to room temperature and concentrated in vacuo. The residue was dissolved in water (40 mL) and CH2Cl2 (75 mL), and basified with Na2CO3 (s). The layers were separated, and the aqueous layer was extracted with CH2Cl2 (2×75 mL). The organic layers were combined, dried over MgSO4, filtered and concentrated in vacuo. The residue was purified by flash chromatography using an ISCO 330 g column eluting with 50-100% hexane/CH2Cl2. Appropriate fractions were collected and concentrated in vacuo to give (E)-benzyl 2-methyl-3-(2-nitroprop-1-enyl)phenylcarbamate (2.4714 g, 39.5% yield) as a yellow solid, LC/MS (M+H)=327.16. 0.6875 g of desired product (75% pure by HPLC) was also collected.

1. concentrationconcentrated in vacuo
2. dissolutionThe residue was dissolved in water (40 mL)
3. customThe layers were separated
4. extractionthe aqueous layer was extracted with CH2Cl2 (2×75 mL)
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe residue was purified by flash chromatography
9. washeluting with 50-100% hexane/CH2Cl2
10. customAppropriate fractions were collected
11. concentrationconcentrated in vacuo