Studies on peptides. LXXXII. Synthesis of [4-Gln]-neurotensin by the methanesulfonic acid deprotecting procedure.

Abstract
In order to examine the side reaction at the tyrosine residue, i.e., O-sulfonation, that occurs during the methanesulfonic acid deprotection of Arg (p-methoxybenzenesulfonyl), [4-Gln]-neurotensin was synthesized as a model peptide. A mixture of cation scavengers, anisole-thioanisole-o-cresol (1 : 1 : 1), suppressed this side reaction sufficiently for practical peptide synthesis.