Synthesis of 2-[[1-oxo-2-(substituted amino)propyl]amino]-4,5,6,7-tetrahydrobenzo[b]thiophen-3-carboxylic acid ethyl esters as potential local anesthetic agents.

The synthesis of a series of 10 compounds related to 2-[[1-oxo-2-substituted amino)propyl]amino]-4,5,6,7-tetrahydrobenzo[b]thiophen-3-carboxyli c acid ethyl esters (III-XII) that are structurally-related to carticaine and the results of a study of their biological activity are reported. Most of the these compounds showed significant activity at lower concentrations when evaluated for local anesthetic activity using the frog-foot withdrawal reflex, the guinea pig wheal derm and the rabbit corneal reflex tests. Compounds III, V, VII and X displayed the shortest onset times and the longest duration of activity, compared to the model drug lidocaine.