Metabolism of nealbarbitone

The human metabolism of 5-allyl-5-neopentylbarbituric acid (nealbarbitone, Censedal), taken orally, has been studied. Comparison of the gas chromatography—mass spectra of extracts from urine with the spectra of model compounds showed nealbarbitone diol (III) to be the only urinary metabolite present in significant amount (about 30–40% of dose); the rate of excretion of diol reached a maximum about 36 h after ingestion of a single 300 mg dose. Treatment of nealbarbitone with a model oxidase of the Udenfriend type resulted only in oxidation of the allyl side-chain to the 2-oxopropyl derivative, in low yield.