Ethanimidamide, N,N-dimethyl-N'-phenyl-

Preparation

To a round-bottomed flask equipped with a mechanical stirrer, dropping funnel, and condenser with a drying tube is added 32.7 gm (0.376 mole) of dimethylacetamide in 50 ml of dry benzene. While vigorously stirring 23.1 gm (0.152 mole) of phosphorus oxychloride in 50 ml of benzene is added dropwise at such a rate as to keep the temperature at 20-25°C. The reaction mixture is allowed to stand for 18 hr, at which time a yellow oil separates. The yellow oil is suspended in the reaction medium by vigorously stirring, and then 11.6 gm (0.125 mole) of aniline previously dissolved in 50 ml of benzene is added dropwise, keeping the temperature at 35°C. After 6-7 hr stirring at 65-70°C, the difficult-to-filter product is washed by decantation with benzene. The hydrochloride is added to a separatory funnel containing 100 ml of distilled water and 100 ml of benzene. Then a cold solution 2N NaOH is added until the aqueous solution is basic to litmus. The reaction mixture is shaken and the free amidine extracted into benzene. The benzene is separated, and the basic aqueous solution is extracted twice with 100 ml portions of fresh benzene. The combined benzene extracts are dried over potassium carbonate, concentrated under reduced pressure. The residue is distilled using a 30 cm Vigreux column, to afford 11.8 gm (68%), b.p. 75-77°C (0.005 mm Hg).