Triethylamine → 2,2-Dimethyl-3-(1',1',2',2'-tetrachloroethylthio)-1,3-benzoxazin-4-one

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Reaction Conditions

Reaction Steps

A 250-ml flask equipped with condenser, stirrer and thermometer and immersed in an ice bath was charged with 150 ml of dichloromethane, 8.3 g (0.047 mol) of 2,2-dimethyl-1,3-benzoxazin-4-one and 10.9 g (0.047 mol) of 1,1,2,2-tetrachloroethylsulfenyl chloride. Then 4.75 g (0.047 mol) of triethylamine dissolved in 10 ml of dichloromethane was added dropwise over a period of 15 minutes. The resulting solution was stirred at 0° C. for 45 more minutes. The crude reaction mixture was washed three times with equal quantities of water. The organic phase was dried and then stripped of solvent. The resulting residue was washed with 200 ml of hexane and filtered. The dried filter cake, 5.1 g, was unreacted 2,2-dimethyl-1,3-benzoxazin-4-one. The filtrate was stripped of hexane and the resulting residue was chromatographed through 300 g of silica gel using 1 liter of hexane, 1 liter of 3% ether-hexane and 3 liters of 5% ether-hexane to give 2.8 g of 2,2-dimethyl-3-(1',1',2',2'-tetrachloroethylthio)-1,3-benzoxazin-4-one. Analysis, calculated for C12H11Cl4NO2S: %C, 37.81; %S, 8.55. Found: %Cl, 40.0; %S, 8.8. NMR spectra confirmed the assigned structure. The infrared spectra had strong adsorption at 1785, 1600, 1460, 1300, 1240 and 740 cm-1. These spectra also had many distinct, medium-strength adsorption bands in the 800-1700 cm-1 region.

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