反应详情

温度

-78 °C

To a dry 500 mL three-necked flask equipped with a thermometer and a dropping funnel, was added a solution of dry CH2Cl2 (60 mL) and oxalyl chloride (2.7 mL, 34.35 mmol) under Ar. The stirred solution was cooled to −78° C. and a solution of DMSO (4.24 mL, 59.67 mmol) in CH2Cl2 (10 mL) was added dropwise. The solution was stirred for 3-5 min. and 4,5-dichlorobenzene-1,2-dimethanol (2.0 g, 9.71 mmol) dissolved in CH2Cl2-DMSO mixture (25 mL) was added dropwise. The reaction was allowed to continue for 0.5 h and then triethylamine (24 mL, 0.18 mol) was slowly added at −78° C. the reaction mixture was allowed to stir for 10 min. and then slowly warmed to RT. Ice-cold water (50 mL) was added to the reaction mixture and the aqueous layer extracted with CH2Cl2 (2×50 mL) and then dried over CaCl2. Removal of solvent gave the yellow solids of 4,5-dichlorobenzene-1,2-dicarbaldehyde in 78% yield (1.53 g). 1H NMR (500 MHz, CDCl3): δ 10.46 (s, 2H), 8.05 (s, 2H). 13C NMR (125.68 MHz, CDCl3): δ 189.92, 139.07, 135.32, 133.08.

1. customTo a dry 500 mL three-necked flask equipped with a thermometer and a dropping funnel
2. additionwas added dropwise
3. waitto continue for 0.5 h
4. stirringto stir for 10 min.
5. temperatureslowly warmed to RT
6. extractionthe aqueous layer extracted with CH2Cl2 (2×50 mL)
7. dry with materialdried over CaCl2
8. customRemoval of solvent