Amino acid catalyzed condensation of purines and pyrimidines with 2-deoxyribose

Abstract

The view that nucleic acids on the prebiotic earth were formed non-enzymatically and functioned in development of a reproducing system was studied. Mild heating of aqueous mixtures containing 2-deoxyribose, amino compounds and purines or pyrimidines produces derivatives of the purines and pyrimidines in high yield. Among the major products formed are 2,3-dideoxy-3-(1''-pyrimidino)pentose and 2,3-dideoxy-3-(9''-purino)pentose. The mechanism of the reaction includes amine-catalyzed dehydration of the .alpha.,.beta. positions of the sugar followed by addition of the purine or pyrimidine to the double bond. Rapid addition of purines and pyrimidines to .alpha.,.beta.-unsaturated carbonyl compounds (such as acrolein) is a general phenomenon which does not require an amine catalyst. While multiple derivatization of the purines will take place, the N-9 derivative is formed first.