反应详情

Oxalyl chloride (10 ml) is added at 0° C. to (2) (5 g; 19 mmol), and the mixture is stirred until the evolution of gas subsides (20 min). The excess oxalyl chloride is removed by distillation in a water-pump vacuum, the acid chloride is taken up in toluene (10 ml), the toluene solution is added at 0° C. to a solution of hydroquinone (10.5 g; 95 mmol) in pyridine (10 ml) and toluene (5 ml), and the mixture is subsequently stirred at room temperature for 24 hours. The reaction mixture is then transferred into water (200 ml), and the mixture is extracted twice with dichloromethane (50 ml each time). The organic extracts are dried using calcium chloride, hydroquinone (50 mg) is added to the filtrate, and the mixture is evaporated in a water-pump vacuum. The residue is chromatographed on silica gel (toluene/ethyl acetate (5:1), giving 4.5 g (66%) of (3).

1. customThe excess oxalyl chloride is removed by distillation in a water-pump vacuum
2. stirringthe mixture is subsequently stirred at room temperature for 24 hours
3. extractionthe mixture is extracted twice with dichloromethane (50 ml each time)
4. customThe organic extracts are dried
5. additionis added to the filtrate
6. customthe mixture is evaporated in a water-pump vacuum
7. customThe residue is chromatographed on silica gel (toluene/ethyl acetate (5:1)