THE LOCAL ANAESTHETIC PROPERTIES OF CERTAIN HETEROCYCLIC COMPOUNDS

¹ From the Department of Pharmacology, University of Edinburgh, and the Department of Chemistry, Heriot-Watt College, Edinburgh

A study of -amino-ketones containing thiazole and furane nuclei by the corneal method has shown them to be too irritant to have any value as local anaesthetics. Four pyrazoline derivatives, of a type already known to possess local anaesthetic properties, were examined more extensively. Three of these were more potent and less toxic than cocaine, and were not at all irritant. The introduction of an o-n-butoxy-group into one of the substituent phenyl nuclei appears to have a beneficial effect on the properties of the molecule as a whole. Local anaesthesia was also caused by the unsaturated piperidino-ketones from which the pyrazolines were prepared, but they proved to be more irritant than cocaine.