engleski

Synthesis and structure of dehydro-4-iminoallantoin and its covalent adducts

Representations of two consecutive products of the Denicke reaction were shown to be incorrect. Oxidation of uric acid by ferricyanide in aqueous ammmonia gives 5-amino-4-iminoallantoin and 1, 5-diamino-3, 7-dioxo-2, 4, 6, 8-tetraazabicyclo[3.3.0]octane, while methylated uric acids afford only the corresponding end products. The key dehydro-4-iminoallantoin arose on exposure of the primary adduct 4 to dilute acetic acid ; a direct route to 4-iminoallantoin was provided by oxidation of 4-iminoallantoin with iodine. Both dehydro-allantoin and its 4-imino analoque 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.

uric acid ; oxidation ; 5-amino-4-iminoallantoin ; 1 ; 5-diamino-3 ; 7-dioxo-2 ; 4 ; 6 ; 8-tetraazabicyclo[3.3.0]octane ; dehydo-4-iminoallantoin ; 4-iminoallantoin

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