TETRAALKYLBARBITURIC ACIDS

¹ From the Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee

Eight tetrasubstituted barbituric acids have been prepared and described; five of these are new compounds. Of the many other (less accessible) isomers it is probable that a large number will be sufficiently soluble in water to be active intravenously.

These compounds have been tested pharmacologically in mice and in rabbits.

Those members of the series which are sufficiently soluble and sufficiently active to produce effects on intravenous administration (dimethylbarbital, dimethylipral, dimethyldial, dimethylneonal, tetramethylbarbituric acid, 1,3-diethyl-5,5-dimethylbarbituric acid) have these properties in common:

(1) They produce marked physiologica1 effects in doses smaller than do the corresponding 5,5-disubstituted barbituric acids, although these effects may be of a different nature.

(2) They are rapidly inactivated in the body.

(3) The onset of action is almost immediate.

Dimethylneonal and 1,3-diethyl-5,5-dimethylbarbituric acid are almost purely narcotic in their action; dimethyldial, almost purely convulsant. The other drugs have both convulsant and narcotic effects, the latter being more prominent at higher doses. The convulsant action is in general much more pronounced in mice than in rabbits.