Local anaesthetic activity of some new substituted acylamides II.

Six new substituted acylamides, chemically related to lignocaine were studied for local anaesthetic activity and toxicity in mice, frogs and guinea pigs. Only one of these compounds, w-pyrrolidino 2, 3, 5, 6 tetramethyl acetanilide was found to possess potency comparable to lignocaine with a slightly higher therapeutic index. Study of the S.A.R. of this group indicated that by removal of two methyl groups at position 3 and 5 in the above compound, a local anaesthetic with greater potency than lignocaine may be obtained. Further exploration of the potentialities of a compound having pyrrolidine group as a part of basic side chain is indicated.