Synthesis of a ferrocenyl uracil PNA monomer for insertion into PNA sequences

Abstract

The deprotection of the tert-butyl group of a ferrocenyl uracil Peptide Nucleic Acid (PNA) monomer, Fmoc-aeg(R)-O t Bu ( 1) was achieved using a two step synthesis involving hydrolysis in basic conditions to give first the zwitterion of +NH 3-aeg(R)-O − ( 7). Compound 7 was reacted in situ with N-(9-fluorenylmethoxycarbonyloxy)succinimide to obtain the expected compound Fmoc-aeg(R)-OH ( 2) (Abbreviations: Aeg = (2-aminoethyl)-glycine; Fmoc = 9-fluorenylmethoxycarbonyl; O t Bu = tert-butyl; R = 5-( N-ferroce-nylmethylbenzamido)uracyl).