Purine nucleotide catabolism in rat liver. Certain preliminary aspects of uricase reaction
We investigated the mechanism of action of uricase, which oxidizes uric acid to allantoin, in the rat. Allantoin may decompose chemically to urea and hydantoin, containing the carbons in positions 2 and 8 of the purine ring, respectively. These carbons ar
Synthesis of [3-14C]- and [5-14C]-labelled 5-nitro-1,2,4-triazol-3-one (NTO) and study of its chemical decomposition
The chemical decomposition of NTO 1 and its corresponding amine ATO 2 was investigated. To make easier the identification of the decomposition products, we synthesized 14C-labelled NTO and ATO. Our results confirmed the high stability of the NTO triazolone ring. Its scission can be achieved partially by sulfuric acid under intensive heat and pressure. The triazolone ring of ATO was cleaved in alkaline solution. Carbon dioxide is evolved leaving a polar compound assumed to be aminoguanidine. The deamination of ATO was achieved by nitrosation. In dilute HCl (0.15 N), 2 equivalents of NO2- led to the triazolone 4, through a radical de-diazotation of the diazo intermediate. With 3 to 10 equivalents of NO2-, the nitrosation leads exclusively to the azide 6.
Le Campion,De Suzzoni-Dezard,Robic,Vandais,Varenne,Noel,Ouazzani
p. 1203 - 1213
(2007/10/03)
In vivo and in vitro studies of urea formation from a ω-1 hydroxybarbiturate: Proxibarbal
Proxibarbal-ω-1 hydroxybarbiturate undergoes more easily than non hydroxylated barbiturates a ring opening and yields urea. In vivo and in vitro studies of this degradation were performed, under biomimetic conditions, and the mechanism is elucidated.