After incorporation of this unit into an oligoribonucleotide by standard phosphoramidite chemistry, treatment with ammonia, methylamine, or higher alkylamines, including those bearing tethered functional groups, leads to displacement of 4-chlorophenol with resultant installation of a 4-amino group, i.e., producing the desired N4-alkyl-C residues.⁽¹⁾

Ref:

1. Allerson, C. R.; Chen, S. L.; Verdine, G. L. J. Am. Chem. Soc. 1997, 119, 7423-7433.