Pyridine → 2-Ethylcarbonate Ethylmaleimide

Participants

Reaction Steps

Hydroxy ethylmaleimide (29.87 g, 0.212 moles) and pyridine (16.7 g, 0.212 moles) were dissolved in THF (170 mL) and the solution was stirred at room temperature. Ethyl chloroformate (22.97 g, 0.212 moles) was added dropwise and stirred for 90 minutes. The pyridine salt was filtered off and the solution was combined with 200 mL of a 1N HCl solution. The product was extracted with methylene chloride and washed with a 1N HCl solution followed by water and then dried over magnesium sulfate. The red solution was concentrated and the red crystals purified by sublimation yielding white crystals, m.p. 52° C. (34.76 g, 77.04% ). 1H-NMR (CDCl3), δ, ppm): 1.26-1.34 (3H, —CH3, t), 3.81-3.87 (2H —NCH2—, t), 4.14-4.25 (2H, δ-CH2OC═O, q), 4.25-4.30 (2H, β-CH2O—, t), 6.74 (2H, —CH═CH—, s). 13C—NMR (CDCl3, δ, ppm): 14.2 (1C, —CH3), 36.8 (1C, —NCH2—), 64.3 (1C, δ—CH2O), 64.5 (1C, δ—CH2—), 134.4 (2C, —CH═CH—), 154.9 (1C, O(C═O)O), 170.4 (2C, —C═O).

Provenance & Evidence