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Proceedings Paper

Intrinsic selectivity in some prebiotic reactions of urazole with sugars
Author(s): Vera M. Kolb; Patricia A. Colloton
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Paper Abstract

Urazole (1,2,4-triazolidine-3,5-dione) (1), 4-methylurazole (12), and its carbon analog, 4,4-dimethylpyrazolidine-3,5-dione (18), react with 2-deoxy-D-ribose (2-deoxy-D-erythro-pentose; 6) in an aqueous solution at room temperature in a regioselective manner (a single substitution on a hydrazidic nitrogen, no reaction on the imide nitrogen) to give a mixture of four nucleosides. These are α and β pyranosides (p) and α and β furanosides (f). The α p forms in a stereoselective manner. A crystalline precipitate is formed in each of the above reactions, which is an exclusive enantiospecific product, 1R, 2R α p. 1 with 2-deoxy-L-ribose (10) gives a precipitate with the exclusive 1S, 2S α p stereochemistry. With 2-deoxy-D-glucose (2-deoxy-D-arabino-hexose; 7) the reaction with 1 is stereospecific, since only one isomer, β p, forms in the solution. Causes of enhanced reactivity of 1 with sugars were also studied. It was found that cyclic hydrazide analogs of 1, such as 12 and 18, are reactive, but open-chain analogs, 1,2,-diacetylhydrazine (21) and 1,2-dicarbethoxyhydrazine (22), are not. Although this reactivity assessment was done qualitatively and under restrictive reaction conditions, it still may be valuable for understanding α -effect of hydrazide nucleophiles. The prebiotic significance of our results is discussed.

Paper Details

Date Published: 10 February 2004
PDF: 14 pages
Proc. SPIE 5163, Instruments, Methods, and Missions for Astrobiology VII, (10 February 2004); doi: 10.1117/12.511738
Show Author Affiliations
Vera M. Kolb, Univ. of Wisconsin/Parkside (United States)
Patricia A. Colloton, Univ. of Wisconsin/Parkside (United States)


Published in SPIE Proceedings Vol. 5163:
Instruments, Methods, and Missions for Astrobiology VII
Richard B. Hoover; Alexei Yu. Rozanov, Editor(s)

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