99-16-1Relevant articles and documents
Polar compounds isolated from the leaves of albertisia delagoensis (menispermaceae)
Hawkes, Geoffrey E.,De Wet, Helene,Li, Jia
, p. 9153 - 9160 (2011)
Aqueous infusions of the leaves of the shrub Albertisia delagoensis (Menispermaceae) are used in South Africa in traditional Zulu medicine to alleviate a variety of symptoms, including fever, and intestinal problems. We report the analysis of such an aqueous extract using the HPLC-NMR technique. A number of polar compounds were identified, including proto-quercitol, nicotinic acid, allantoic acid, 3,4-dihydroxybenzoic acid, phthalic acid and the aporphine alkaloid derivative roemrefidine. Allantoic acid and roemrefidine have been fully characterised by 1H- and 13C-NMR and mass spectrometry. Earlier reports of antiplasmodial activity of roemrefidine and of A. delagoensis extracts are correlated with this study and with the antipyretic properties of neutral aqueous extracts.
THE MECHANISM FOR THE CONVERSION OF URIC ACID INTO UROXANATE AND ALLANTOIN A NEW BASE-INDUCED 1,2-CARBOXYLATE SHIFT
Poje, M.,Sokolic-Maravic, Lea
, p. 6723 - 6728 (2007/10/02)
Alkaline permanganate oxidation of uric acid (1), particularly the late stages of the transformation into uroxanate (7) and allantoin (3), was studied by means of isotope-position labelling.A clear-cut degradation procedure developed for distinguishing among carbonyl and α-aminal carbon atoms in these products demonstrated conclusively that the carboxylic carbon of 7 and the 4-carbonyl carbon of 3 have their origin in C(5) of uric acid (1).None of the mechanisms that have been proposed for this reaction would have predicted this result.Isotope-labelling evidence, in combination with other data, revealed the sequence of events and identities of species involved in oxidative transformation of 1; the carbon-skeleton rearrangement of the first transient intermediate 4 must occur by a 1,2-carboxylate shift to give allanatoin-5-carboxylate (6) which either decarboxylates to allantoin (3) or else undergoes hydrolytic ring opening to uroxanate (7).
