[Local anesthetics. CVII. Local anesthetic effects of phenylcarbamates--the effect of connecting chain modification].

The preceding study of the effect of the branching of the connecting chain by the metoxymethyl-, ethoxymethyl- and propoxymethyl group on the alpha carbon on local anaesthetic activity was a stimulus for the preparation of 16 drugs of the group of 1-ethoxyethoxymethyl-2-(1-pyrrolidinyl-), 2-piperidino- and 2-(1-perhydroazepinyl) ethyl esters of o-, m- and p-alkoxyphenylcarbamic acids. The discontinuation of the substituent on the alpha carbon of the connecting chain by another oxygen atom (introduction of an ethoxyethoxymethyl group) has a positive effect on surface and infiltration anaesthesia. Of the prepared agents, 2-piperidino- and 2-(1-perhydroazepinyl-) derivatives with a hexyl or heptyloxy group in the o-position of the benzene ring were most effective; they exceeded the standards cocaine and procaine more than one hundred times. p-Derivatives were least effective; in some cases their indices of effectiveness did not achieve the effectiveness of the standards in both surface and infiltration anaesthesia under study. Acute toxicity of all drugs lies within the range of the toxicities of the standards.