18O and secondary 2H kinetic isotope effects confirm the existence of two pathways for acid-catalysed hydrolyses of α-arabinofuranosides

Abstract

The ¹⁸O kinetic isotope effect on the HClO₄-catalysed hydrolysis of 4-nitrophenyl [1-¹⁸O]-α-arabinofuranoside (k₁₆/k₁₈) is 1.023 ± 0.003 at 80.0 °C; that for isopropyl (1-¹⁸O]-α-arabinofuranoside is 0.988 at 30.2 °C and the secondary deuterium effect on the hydrolysis of [2-²H]propan-2-yl α-arabinofuranoside (k_H/k_D) is 0.979. The nitrophenyl glycoside reacts with exocyclic C–O cleavage and the propan-2-yl glycoside by endocyclic C–O cleavage.