反应详情

温度

24 °C

Cyclobut-1-enecarboxylic acid (300 mg, 3.06 mmol), glycine methyl ester hydrochloride (423 mg, 3.37 mmol), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (704 mg, 3.67 mmol) were added to a round-bottomed flask. After addition of CH2Cl2 (6 mL) and N,N-diisopropylethylamine (1.07 mL, 6.12 mmol), the reaction mixture was stirred for 12 h at 24° C. When the reaction was complete, EtOAc (60 mL) was added and the resulting solution was washed with 1N aq HCl (3×20 mL) and 5% aq NaHCO3 (3×20 mL). The combined aqueous HCl wash (60 mL) was re-extracted with ethyl acetate (2×30 mL). The combined organic solution was washed with the separated aqueous NaHCO3 solution. The combined organic solution was dried over anhydrous Na2SO4. The solvent was evaporated and the residue was purified by neutral aluminum oxide column chromatography with 40% EtOAc/CH2Cl2 (216 mg, 42% yield). The purified fractions were concentrated and diluted with dry CH2Cl2 (3 mL) (complete concentration by vacuum should be avoided to prevent radical or ionic polymerization). In the solution state, monomer 1 is stable. For long term storage, the solution was kept at −80° C. to prevent possible decomposition. 1H-NMR (400 MHz, CDCl3) δ 6.67 (t, J=1.2 Hz, 1H), 6.09 (br s, 1H), 4.11 (d, J=5.2 Hz, 2H), 3.78 (s, 3H), 2.73 (t, J=3.2 Hz, 2H), 2.49 (td, J=3.2 Hz, 1.2 Hz, 2H); 13C-NMR (100 MHz, CDCl3) δ 170.6, 162.7, 141.5, 140.9, 52.5, 40.9, 28.6, 26.5; HRMS (ESI) calcd for C8H12NO3 [M+H]+ 170.0817, found 170.0809.

1. washthe resulting solution was washed with 1N aq HCl (3×20 mL) and 5% aq NaHCO3 (3×20 mL)
2. washThe combined aqueous HCl wash (60 mL)
3. extractionwas re-extracted with ethyl acetate (2×30 mL)
4. washThe combined organic solution was washed with the separated aqueous NaHCO3 solution
5. dry with materialThe combined organic solution was dried over anhydrous Na2SO4
6. customThe solvent was evaporated