Local anesthetics. 2-Diethylamino-2',6'-acylxylidides

A series of C-alkylated derivatives of lidocaine has been synthesized, and the local anesthetic potencies were determined. Activity reached a miximum with the butyroxylidide (alpha-ethyl group), but toxicity increased regularly with the number of carboons in the side chain. Spectral data showed the compounds to exist as associated H-bonded structures, the free base most likely as intramolecularly bonded trans amides and the hydrochlorides most likely as associated cis amindes.