Norchlorcyclizine → Cetirizine ethyl ester

Participants

Reaction Conditions

Reaction Steps

10 gr. (0.035 mole) of 1-[(4-chlorophenyl)phenylmethyl]piperazine, 8.8 gr. (0.0525 mole) of ethyl 2-chloroethoxyacetate and 50 ml. of triethylamine were introduced into a pressure vessel. The mixture was stirred at 135° C. for 10 hours. It was cooled to 20° C. and filtered. The filtrate was evaporated and then distilled at 10 mbar pressure in order to remove the excess of the unreacted ethyl 2-chloroethoxyacetate. The oily residue obtained is sufficiently pure for the preparation of cetrizine by hydrolysis. The residue was purified over a silica gel chromatographic column. 13 gr. of ethyl [2-[4-[(4-chlorophenyl)phenylmethyl]-1-piperazinyl]ethoxy]acetate is obtained as dark red oil (89.4% yield).

Provenance & Evidence