Hydrochloric Acid → Efletirizine

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Reaction Steps

In a round-bottomed flask fitted with a mechanical stirrer, a Nitrogen inlet and a condenser, 30 g (0.065 mole) of 2-[4-[bis(4-fluorophenyl)methyl]-1-piperazinyl]ethoxyacetamide dihydrochloride are added to a mixture of 325 ml of ethanol, 130 ml of a 1 N aqueous sodium hydroxyde solution and 62 ml of a 6.3 N aqueous sodium hydroxide solution. The mixture is heated under reflux and under a Nitrogen atmosphere for 1.5 hours. The reaction mixture is then cooled down to room temperature and its pH is adjusted to 5 with 78 ml of a 5 N aqueous hydrochloric acid solution. Water is added, and ethanol is evaporated off under vacuum using a rotary evaporator. The resulting aqueous phase is extracted with dichloromethane. The organic phase is dried over anhydrous sodium sulphate and evaporated to dryness to give 25 g of crude efletirizine as an amorphous solid, 5 g of which are recrystallized in acetonitrile.

Provenance & Evidence