Scope and Limitations of Barbituric and Thiobarbituric Amino Acid Derivatives as Protecting Groups for Solid‐Phase Peptide Synthesis: Towards a Green Protecting Group

DMB (Dimethylbarbituric) and DETB (Diethylthiobarbituric) are both barbituric thiobarbituric acid derivatives respectively, that forms enamines with the Nα amine of amino acids. These compounds were found to be stable crystalline solids show stability in standard acidic basic conditions used for solid-phase peptide synthesis (SPPS) strategies. protecting groups cleaved by a mild solution 2 % hydrazine hydrate DMF hydroxylamine DMF, at short reaction times. Their use SPPS showed DMB-protected acids allow preparation peptides therefore could an alternative Fmoc strategy currently used. A further advantage these is their does not involve concourse phosgene they considered greener than carbamate-based one.