Fmoc-Asp-ODmab

Quasi-orthogonally-protected Asp derivative.The Dmab group can be removed selectively in the presence of tBu-based protecting groups by treatment with 2% hydrazine in DMF ^[1], making this derivative an extremely useful tool for the preparation of cyclic peptides by Fmoc SPPS or for library synthesis. Occasionally sluggish cleavage of the aminobenzyl moiety is observed ^[2,3]. In these instances, washing the support with 20% DIPEA in DMF/water (9:1) ^[2] or HCl in dioxane ^[4] has been found to be efficacious. For the on-resin synthesis of side-chain to side-chain lactam bridged peptides, the combination of Lys(ivDde) and Asp(ODmab) is particularly advantageous since both side-chains can be simultaneously unmasked in a single step.To avoid aspartimide formation, it is advisable to employ an Hmb- or Dmb-protected derivative for introduction of the preceding residue.For applications of this derivative in the synthesis of cyclic peptides, see references ^{[5 - 7]}.

Associated Protocols and Technical Articles
Cleavage and Deprotection Protocols for Fmoc SPPS

Literature references

^[1] W. C. Chan, et al. (1995) J. Chem. Soc., Chem. Commun., 2209.
^[2] S. Künzel, et al. Poster 17 presented at Solid Phase Synthesis & Combinatorial Libraries, Southampton, September 2001.
^[3] K. F. Medzihradszky, et al. (2002) Lett. Pept. Sci., 8, 1.
^[4] Albericio, et al.Poster 44 presented at American Peptide Symposium, San Diego 2005..
^[5] M. Cudic, et al. in ′Peptides 2000, Proc. 26th European Peptide Symposium′, J. Martinez & J.-A. Fehrentz (Eds), Paris, Editions EDK, 2001, pp. 203.
^[6] M. Cudic, et al. (2000) Tetrahedron Lett., 41, 4527.
^[7] J. P. Malkinson, et al. (2003) Org. Lett., 5, 5051.

Replaces: 04-12-1176

Color (visual): white to slight yellow to beige
Appearance of substance (visual): powder
Identity (IR): passes test
Enantiomeric purity: ≥ 99.0 % (a/a)
Purity (TLC(157A)): ≥ 97 %
Purity (TLC(CMA2)): ≥ 97 %
Assay (HPLC, area%): ≥ 95.0 % (a/a)
Solubility (1 mmole in 2 ml DMF): clearly soluble
Water (K. F.): ≤ 1.0 %

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