反应详情

To a 100 mL flask with a Dean-Stark condenser and an argon inlet was added N-Boc-L-serine tert-butyl ester 2 (5.00 g, 19.1 mmol), ethyl-2-cyanopropionate (3.65 g, 28.7 mmol), p-toluenesulfonic acid monohydrate (0.200 g, 1.05 mmol) and anhydrous toluene (60 mL). The reaction mixture was heated to reflux while stirring. Solvent was removed through the Dean-Stark trap and replaced with an equal amount of fresh toluene. After refluxing for 6 h, the reaction mixture was cooled to room temperature. The solution was washed once with saturated aqueous NaHCO3, twice with H2O, and twice with saturated aqueous NaCl. The organic layer was separated, dried over anhydrous MgSO4, and concentrated to a viscous yellow oil. 1H NMR (CDCl3): δ 1.43 (m, 21H, CH3—CH—NH—, 2 (CH3)3), 3.25 (s, 1H, CH3-CH—CN), 3.85 (t, 2H, CO2, —CH2—CH—), 3.85 (t, 2H, CO2—CH2—CO2Bu), 4.25 (s, 1H, NH—CH—CH2—), 5.55 (d, 1H, NH). This material can be converted to the cyanoacrylic monomer by following the general procedure set forth above for the alanine-derived monomer.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux
3. customSolvent was removed through the Dean-Stark trap
4. temperatureAfter refluxing for 6 h
5. washThe solution was washed once with saturated aqueous NaHCO3, twice with H2O
6. customThe organic layer was separated
7. dry with materialdried over anhydrous MgSO4
8. concentrationconcentrated to a viscous yellow oil