Convulsant, anticonvulsant and anaesthetic barbiturates. 5-Ethyl-5-(3'-methyl-but-2'-enyl)-barbituric acid and related compounds.

Barbiturates derived by minor structural changes to the butenyl sidechain of the convulsant 5-ethyl-5-(3'-methyl-but-2'-enyl)-barbituric acid are almost devoid of convulsant activity, but all have anaesthetic and anticonvulsant effects. Anticonvulsant activity is also observed in the convulsant barbiturate. Increased lipophilic character does not increase anaesthetic potency, only speed of onset, and anticonvulsant activity is reduced in the more lipophilic compounds. The stereochemistry at the 3'-position of the sidechain is vitally important to convulsant activity, and also influences anticonvulsant potency.