Etomidate (ETM)

Etomidate is a short acting intravenous anaesthetic agent used for the induction of general anaesthesia and for sedation for short procedures such as reduction of dislocated joints, tracheal intubation and cardioversion. Etomidate is prepared by the following procedure. It illustrates a special case of obtaining derivatives of imidazole by interaction of α-aminocarbonyl compounds with thiocyanates. The reaction of α-methylbenzylamine with ethyl chloroacetate gives N-ethoxycarbonylmethyl-N-1-phenylethylamine, which undergoes further formylation by formic acid. The resulting N-ethoxycarbonylmethyl-N-formyl-N-1-phenylethylamine undergoes further C-formylation by ethyl formate in the presence of sodium ethoxide. Etomidate is highly protein bound in blood plasma and is metabolised by hepatic and plasma esterases to inactive products. It exhibits a bi-exponential decline.