The Nim-(2,4-dimethylpent-3-yloxycarbonyl)(Doc) group, a new nucleophile-resistant, HF-cleavable protecting group for histidine in peptide synthesis

Abstract

The 2,4-dimethylpent-3-yloxycarbonyl group as protection for the imidazole ring of histidine combines several properties that makes it ideal for solid phase peptide synthesis with Boc chemistry; it is readily cleaved by liquid HF, stable to trifluoroacetic acid, soluble in apolar organic solvents and highly resistant to nucleophiles, thereby avoiding the danger of N^im to N^α transfer and premature cleavage by other nucleophiles during solid phase synthesis.