New synthetic procedure for the antiviral sulfonate carbosilane dendrimer G2-S16 and its fluorescein-labelled derivative for biological studies

The anionic carbosilane (CBS) dendrimer with sulfonate groups G2-S16 is a promising compound for the preparation of a microbicide gel to prevent HIV infection. However, until now its synthesis required aggressive conditions. Hence, a reliable synthetic procedure is very important to face GMP conditions and clinical trials. In this study, G2-S16 has been prepared by a new approach that involves the addition of an amine-terminated dendrimer to ethenesulfonyl fluoride (C2H3SO3F, ESF) and then transformation to the sulfonate dendrimer by treatment with a base. This strategy also makes feasible the synthesis of a labelled sulfonate dendrimer (G2-S16-FITC) to be used as a molecular probe for in vivo experiments. Interestingly, G2-S16-FITC enters into human peripheral blood mononuclear cells (PBMCs).