Reactions of Exocyclic Substituents of Nucleic Acid Bases and their Derivatives

Abstract

Considerable light is shed on the problems of reactivity and chemical modification of nucleic acids by reactions involving exocyclic substituents of the purine and pyrimidine bases, i. e., the amino groups of cytosine, adenine, or guanine, and the carbonyl groups of uracil, guanine, xanthine, and their derivatives, and also reactions of the sulphur atom of thio derivatives (minor components of RNA). As was mentioned previously (see Chapter 3), n electrons of the nitrogen atoms of amino groups and of the oxygen atom of carbonyl groups of the nucleic acid bases (and their derivatives) react strongly with the π electron system of the heterocyclic ring, and consequently the properties of the corresponding components of the nucleic acids differ greatly from the properties of simple amines, amides, or thioamides.