Technical Note:

1. This di-sulfonated building block is recommended for post-synthetic water-solubilization of hydrophobic, molecules for applications in biological media, especially organic dyes, fluorophores, azo dyes^[1], bodipy^[2], coumarin^[3] and xanthene dyes^[4].

This includes organic supramolecular compounds such as cryptophanes^[5], through aminolysis reactions of activated esters, activated carbamates (or carbonates) and isothiocyanates. Such reactions can be performed either in aqueous media

(Schotten-Baumann conditions), or in anhydrous organic media (by converting this di-sulfonated taurine analog into the

corresponding tributylammonium or tetrabutylammonium salt^[2,4]). Such methodology is also applicable for sulfonation of

biomolecules such as peptides and nucleic acids, for fine-tuning their net electric charge^[6].

A further derivatization of this unusual amine with 3-azidopropanoic acid, 3-mercaptopropanoic acid, or 4-pentynoic acid,

provides a di-sulfonated linker that is reactive in either “click” reactions (1,3-dipolar cycloadditions), SNAr or Sonogashira

cross-couplings^[1].

References:

1. Chem.-Eur., J., 2013, 19, 1686.

2. New J. Chem., 2013, 37, 1016.

3. Dyes Pigm., 2014, 110, 270.

4. Tetrahedron Lett., 2010, 51, 3304.

5. Chem. Commun., 2011, 47, 9702.

6. Bioconjugate Chem., 2014, 25, 1000.