CO-NH

sulfur derivatives of monoethyl, dimethyl, diethyl and dipropyl barbituric acids. Whiteley (3) prepared phenyl thiobarbituric acid. Dox and Plaisance (4) made derivatives of thiobarbituric acid with a number of aromatic aldehydes and Dox and Yoder (5) synthesized a spirocyclohexane of thiobarbituric acid. Recently there have appeared brief reports on the preparation of some new thio derivatives (6, 7) similar in type to those prepared by one of us (Dox). The physiologic action of the diethyl thiobarbituric acid was reported in brief by Fisher and von Mering (8) who concluded that the substance possessed high toxicity and low hypnotic power. CHEMISTRY The thiobarbituric acid derivatives contain sulfur in place of oxygen on the urea carbon, as illustrated in the general formula