5676-27-7Relevant academic research and scientific papers
Synthesis and structure of dehydro-4-iminoallantoin and its covalent adducts
Popovic,Sokolic, Lea,Modric, Nevenka,Palkovic,Poje
, p. 317 - 322 (2007/10/19)
Representations of two consecutive products of the Denicke reaction were shown to be incorrect. Oxidation of uric acid (1a) by ferricyanide in aqueous ammonia gives 5-amino-4-iminoallantoin (4) and 1,5-diamino-3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]octane (5a), while methylated uric acids 1b-g afford only the corresponding end products 5. The key dehydro-4-iminoallantoin (6) arose on exposure of the primary adduct 4 to dilute acetic acid; a direct route to 6 was provided by oxidation of 1-iminoallantoin (2) with iodine. Both dehydro-allantoin (8) and its 4-imino analogue 6 form covalent adducts (e.g. with MeOH) at the 5-position. A brief rationale which focusses upon the stepwise nature and regiochemical course of the reaction is presented.
THE MECHANISM FOR THE CONVERSION OF URIC ACID INTO ALLANTOIN AND DEHYDRO-ALLANTOIN. A NEW LOOK AT AN OLD PROBLEM
Poje, M.,Sokolic-Maravic, Lea
, p. 747 - 752 (2007/10/02)
The reaction of uric acids 1 with iodine in alkaline solution yields, on acidification, new dehydroallantoins 11, or normal oxidation products, allantoins 13, depending on whether an excess or a stoichiometric amount of oxidant was used.The structure and regiochemistry of dehydro-allantoins 11 was established by chemical, spectroscopic, and 14C-labelling methods.These experimental results, in combination with other data, generate a new mechanistic scheme for the uricolytic pathway to allantoin, ruling out the intervention of a symmetrical transition state prior to the decarboxylation step.
