Abstract: 1-N-substituted-4-alkoxy-piperidin-4-yl group is disclosed as a protecting reagent for the 2'-hydroxyl of oligo- or poly-ribonuleotides. This protecting group is applicable to the protection of the 2'-hydroxyl group during oligo- or poly-ribonucleotide synthesis. Nucleosides and nucleotides with the 2'-hydroxyl protected with 1-N-substituted-4-alkoxy-piperidin-4-yl group are also described.

Abstract: A process for protecting the 2'-hydroxyl of a nucleoside, which can then be used in the chemical synthesis of polyribonucleotides, comprising the reacting of a protected nucleoside of formula I ##STR1## wherein B is a nucleoside heterocyclic base and R' is a hydroxyl-protecting group,with 1-N-aryl-4-alkoxy-1,2,5,6-tetrahydropiperidine of formula II ##STR2## wherein Ar is an aryl group possessing an electron-withdrawing substituent which renders said protecting group acid labile and R is C.sub.1 -C.sub.

Abstract: A process for the production of a 5-substituted derivative of a 2,3'-anhydro-2'-deoxyuridine preferably corresponding to the following general formula: ##STR1## wherein R.sup.1 represents H, alkyl, aryl, halogeno or CF.sub.3 ; characterized in that it comprises heating a 5-substituted derivative of a 2'-deoxyuridine preferably corresponding to the following general formula: ##STR2## wherein R.sup.1 is as defined above; in the presence of a sulphite transfer reagent and preferably a solvent is disclosed.This process improves the production of valuable intermediates and hence facilitates and reduces the cost of production of pharmacologically-interesting compounds.