In this invention a two steps procedure is described useful to insertfunctional groups to the hyaluronic acid (HA),through the formation, in organic solvent, of a particular active group onhydroxyl groups of HA and subsequent substitution, onthe inserted active group, with a pendant portion containing at least in itsterminal portion a nucleophilic functional group, NH2-R.The group inserted by nucleophilic substitution can contain in another itsterminal portion a further nucleophilic functional group,in a way to be easily exploitable to further chemical functionalizations, suchas an example to obtain the methacrylation of HAfunctional groups, to obtain photocrosslinkable derivatives. Both directderivatives of the proposed process and those obtained bythe further functionalization can be employed to produce hydrogels.
