Figure 6a: Scheme of the intramolecular conversion of phosphorous acid (phosphonic acid) as a possible side reaction during the procedure of ribozyme-mimetic synthesis of interbiomonomeric bond. However the possibility on this type of reaction (transformation from bis-2-OH alkyl H-phosphonate (bis-beta-hydroxyalkyl H-phosphonate) to spirophosphorane (H-tetraoxaspirophosphorane), thru the alkylene H-phosphonate (2-oxo 1, 3-dioxa 2-H 2-phospholane), is increased in dioxane/pyridine [46] and proceeds in our case to some minor extent [39].