反应详情

To a suspension of 10 g (0.026 mole) of the diacid 22 in 100 ml of CH2Cl2 and 7 drops of DMF was added, at 0° C., in a dropwise fashion 12 ml (0.138 mole) of oxalyl chloride. After addition the mixture was allowed to come to room temperature with vigorous evolution of HCl gas and stirred for 2 hours. The resulting homogeneous solution was then cooled in an ice bath and 20 ml of methanol in 40 ml of CH2Cl2 was slowly added. The resulting mixture was stirred for 30 minutes at room temperature and poured into 300 ml of water. The organic phase was removed, washed with 10% NaHCO3, water, dried (Na2SO4) and solvents removed. The crude diester (15 g) was purified via plug filtration with SiO2 /EtOAc/CH2Cl2 (20:80) yielding 7.0 g (65%) of the diester (23):NMR (CDCl3 ) 3.85 (s, 3,OCH3), 4.05 (s,6,CO2Me), 5.1 (s,2,OCH2O), 6.7 and 7.4 (m,3,--C6H3O2R2) 7.35 (s,5,--C6H5), 8.5 (s,2,--C5H2N'.

1. additionAfter addition the mixture
2. temperatureThe resulting homogeneous solution was then cooled in an ice bath
3. stirringThe resulting mixture was stirred for 30 minutes at room temperature
4. customThe organic phase was removed
5. washwashed with 10% NaHCO3, water
6. dry with materialdried (Na2SO4) and solvents
7. customremoved
8. filtrationThe crude diester (15 g) was purified via plug filtration with SiO2 /EtOAc/CH2Cl2 (20:80)