Hydrogen Sulfide → Potassium m-nitrophenyldithiocarbamate

참여 물질

반응 단계

A mixture of 75.0 grams of potassium t-butylate in 500 ml. of t-butyl alcohol is saturated with hydrogen sulfide. With the temperature kept below 35°C. by cooling, a mixture of 120.0 grams of m-nitrophenyl isothiocyanate in 500 ml. of ether is added to the potassium hydrosulfide solution in three portions. After the mixture is stirred an additional 2 hours, the solids are collected by filtration, washed with ether, and dried under vacuum to give 162 grams of potassium m-nitrophenyldithiocarbamate. This salt is added portionwise over about 15 minutes to a stirred ice-cooled mixture of 174 grams of methylene bromide and 65 grams of triethylamine in 600 ml. of dimethylformamide with the reaction temperature at 25°C. to 30°C. After another 5 hours of stirring at room temperature, the mixture is poured into 3.5 liters of ice-water precipitating a light yellow solid. The solids, after drying, are taken up in benzene (ca. 2 liters), filtered free of some insoluble material, and the benzene mixture is saturated with dry hydrogen chloride. The precipitated solids are collected by filtration, washed with benzene, and then stirred vigorously with a water-benzene mixture at 60°C. to 70°C. The benzene layer is separated, washed with water and sodium bicarbonate solution, dried, and concentrated in vacuo to give 102 grams of crude product. The solids are dissolved in 800 ml. of ethanol. The mixture is filtered and diluted with 1200 ml. of ether. Then the mixture is cooled to -35°C. The resulting light yellow solids are collected and vacuum dried to give 84.0 grams of product, melting point 96.0°C. to 97.0°C.

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