Chloride → 3-(Dimethylamino)pyrrolidine-1-carbothioamide

To a suspension of potassium thiocyanate (2.02 g, 20.8 mmol) in acetone (10.7 mL) at 0° C. was slowly added pivolyl chloride (2.6 mL, 21.1 mmol). The mixture was stirred at 0° C. for 3 h. Dimethylpyrrolidin-3-yl-amine (2.44 g, 21.3 mmol) was added slowly at 0° C., and the reaction was allowed to warm to room temperature. After stirring at room temperature overnight, the reaction was concentrated, and concentrated hydrochloric acid (10 mL) was added. The reaction was heated to 95° C. with stirring for 1 h. The mixture was allowed to cool to room temperature, and was extracted with dichloromethane. The aqueous layer was made basic with 20% aqueous sodium hydroxide. The basic solution was extracted with dichloromethane. The organics were combined, washed with brine, dried with anhydrous sodium sulfate, filtered, and concentrated. The mixture was diluted with diethyl ether and filtered to provide pure 3-dimethylamino-pyrrolidine-1-carbothioic acid amide (135) (0.863 g, 23.3%) as a white solid.