Uses
Principal use in toxicology
was in the characterization of cytochrome P450 isozymes.
Ethyl isocyanide and the reduced cytochrome form a
characteristic optical difference spectrum with two peaks in
the Soret Region (type III). The pH equilibrium point (the pH
at which the two peaks are of equal height) varies between different
isozymes.
Preparation
CAUTION: The reaction and distillation should be conducted behind a safety shield. Precautions for handling toxic cyanides should be observed.
To a three-necked flask equipped with a condenser and ground glass stirrer (or Hershberg stirrer) is added 116 gm (0.75 mole) of ethyl iodide and 100 gm (0.75 mole) of silver cyanide. The mixture is refluxed for 2 hr, the stirrer blade raised, the mixture cooled, filtered (see Note a), the solid washed with ether, dried, and 260 gm of a 50% solution of potassium cyanide (2.0 moles) added. The reaction mixture is distilled to afford a mixture of isonitrile and water (see Note b). The crude isonitrile 49.5- 52.3 gm (90-95%) is separated after being salted out of the water. The isonitrile is washed twice with 24-ml portions of ice-cold saturated sodium chloride solution, dried over magnesium sulfate, and fractionally distilled, to afford 25.9-30.3 gm (47-55%), b.p. 77-79°C (760 mm Hg).
