A mild and quantitative procedure for the removal of nucleoside alkoxycarbonyl groups using pig liver esterase or Candida antarctica B lipase

A set of eight mono-, di-, tri- and tetraalkoxycarbonylated nucleosides was tested in order to assess their enzymatic hydrolysis. All the alkoxycarbonyl groups of the assayed substrates, from both carbonate and carbamate functions, were quantitatively hydrolysed using pig liver esterase (PLE) at pH 7 and 60 °C, regardless of the nucleoside base. Quantitative full alkoxycarbonyl groups removal was also reached by Candida antarctica B lipase (CAL B) under mild conditions, but in this case, longer reaction times were required. Thus, PLE appears as an useful catalyst for the mild and quantitative deprotection of nucleoside carbonates and carbamates in the synthesis of modified nucleosides.