Cyanogen bromide and tresyl chloride chemistry revisited: the special reactivity of agarose as a chromatographic and biomaterial support for immobilizing novel chemical groups.

The cyanogen bromide and tresyl chloride (2,2,2-trifluoroethanesulfonyl chloride) methods belong to the best-known activation procedures for solid supports in biochemistry. In both cases the originally proposed reaction mechanisms were revised many years later. In this paper important aspects of these two major activation reactions in connection with the singular polysaccharide support, agarose, will be treated with emphasis on the novel reaction mechanism recently proposed for tresyl chloride. In addition, the special role played by sulfur in the new uncharged alkyl-S-S-gels is examined in connection with the phenomenon of base-atom recognition.