反应详情

A solution of 5-chloro-3-hydroxyisothiazole (4.0 g, 0.03 mole) in 15 ml of dimethyl formamide was added dropwise to a stirred suspension of 60% NaH in oil (1.4 g, 0.035 mole) in 25 ml of dimethyl formamide at 0° C. under N2. After 15 minutes, a solution of 2,5-dimethoxybenzyl chloride (5.6 g, 0.03 mole) in 10 ml of dimethyl formamide was added dropwise and the mixture was stirred at room temperature for 24 hours. The dark reaction mixture was poured into water and extracted with diethyl ether. The diethyl ether extract was washed with water, dried (MgSO4), and concentrated. The residual white solid was purified by column chromatography on silica gel, using diethyl ether/hexane (1/1) as eluant. 5-Chloro-3-(2,5-dimethoxybenzyloxy)isothiazole was obtained as a white solid; 4.7 g; mp 52°-55° C.

1. customThe dark reaction mixture
2. extractionextracted with diethyl ether
3. extractionThe diethyl ether extract
4. washwas washed with water
5. dry with materialdried (MgSO4)
6. concentrationconcentrated
7. customThe residual white solid was purified by column chromatography on silica gel