ethyl acetimidate

Preparation

To a flask cooled to -5°C containing 61.5 gm (1.5 mole) of dry aceto-nitrile and 69.0 gm (1.5 mole) of anhydrous ethanol is added 532 gm (1.5 mole) of gaseous hydrogen chloride. The flask is stoppered and kept for 6 hr at 0°C and 4-5 days in the refrigerator. The resulting precipitate is filtered and washed with dry ether at 0°C. The salt is suspended in 500 ml of anhydrous ether and while stirring vigorously dry ammonia is passed into the suspension for 1.5 hr at -15°C. The resulting ammonium chloride is filtered and the ether solution is fractionally distilled to affect 60.0 gm (45.9%), b.p. 90°C, n²⁴_D 1.415, d₂₃ 0.872.

Purification Methods

It is best to prepare it freshly from the hydrochloride (see below). Dissolve the hydrochloride (123.5g) by adding it slowly to an ice-cold mixture of H2O (500mL), K2CO3 (276g) and Et2O (200mL) and stirring rapidly. The Et2O layer is separated, the aqueous layer is extracted with Et2O (100mL), the combined Et2O layers are dried (MgSO4), evaporated and the residual oil is distilled through a glass helices packed column (70x1.2cm). The yield is 19g (22%). [Glickman & Cope J Am Chem Soc 67 1020 1945, Chaplin & Hunter J Chem Soc 1118 1937, Hunter & Ludwig Methods Enzymol 25 585 1972.]