General description

This pseudoproline dipeptide is undoubtedly the most effective and simplest to use tool for overcoming aggregation and enhancing peptide quality in Fmoc SPPS for peptide containing the Leu-Thr dipeptide motif. It consists of a dipeptide in which the threonine residue has been reversibly protected as a structure-breaking proline-like TFA-labile oxazolidine. The reason the pseudoproline residue is introduced as a dipeptide is because it avoids the need to acylate the hindered oxazolidine nitrogen. This has the added advantage of extending the peptide chain by two residues in one step. The threonine residue is regenerated during the normal TFA-mediated cleavage reaction.

Associated Protocols and Technical Articles
Cleavage and Deprotection Protocols for Fmoc SPPS
Overcoming Aggregation in Fmoc SPPS

Linkage

Replaces: 05-20-1009

Analysis Note

Color (visual): white to slight yellow to beige
Appearance of substance (visual): powder
Identity (IR): passes test
Optical rotation α 25/D (c=1 in CH₂Cl₂): -33.0 - -28.0 °
Purity (TLC(CMA2)): ≥ 97 %
Purity (TLC(157A)): ≥ 97 %
Assay (HPLC, area%): ≥ 97.0 % (a/a)
Single impurities (HPLC, area%): ≤ 2.00 % (a/a)
Acetate (IC): ≤ 0.1 %
Ethyl acetate (HS-GC): ≤ 2.0 %

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