KINETICS AND MECHANISM OF THE ACID-CATALYZED HYDROLYSIS OF REGIOISOMERIC BENZOTRIAZOLE AND 8-AZAADENINE NUCLEOSIDES



: KAPPI R, KAZIMIERCZUK Z, JARVINEN P, SEELA F, LONNBERG H

Publisher: ROYAL SOC CHEMISTRY

: 1991

Royal Society of Chemistry. Journal: Perkin Transactions 2

JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2

: J CHEM SOC PERK T 2

: 5

: 595

: 600

: 6

: 0300-9580

DOI: https://doi.org/10.1039/p29910000595


First-order rate constants for the acid-catalysed hydrolysis of ribo- and 2'-deoxyribonucleosides derived from 1H-, 2H- and 3H-benzotriazoles and 7H-, 8H- and 9H-8-azaadenines have been determined over a wide pH range. Partial rate constants for reactions via mono- and di-protonated substrates have been calculated with the aid of spectrophotometrically determined pK(a) values. The mechanisms of hydrolysis reactions have been elucidated by the effects that polar substituents on the base moiety exert on the protonation and heterolysis steps. Reactivities of various regioisomers have been compared, and reasons for the exceptional hydrolytic instability of N3-alkylated purine nucleosides briefly discussed.



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