Fmoc-AEPipAc-OH.2HCl is an Fmoc-protected, piperazine-containing noncanonical building block used to introduce a flexible aminoethyl-piperazine-acetic-acid unit into peptides and peptide-like molecules. The piperazine ring adds a basic, conformationally distinct heterocyclic element that can be useful when tuning charge distribution, linker geometry, solubility or spacing between pharmacophoric groups.

The correct dihydrochloride composition for CAS 204320-65-0 is C₂₃H₂₉Cl₂N₃O₄ with molecular weight 482.40 g/mol. This is important for procurement and reaction-equivalent calculations because a one-HCl formula is inconsistent with the “2HCl” product identity.

Product Information

What AEPipAc Adds to a Peptide

AEPipAc introduces a piperazine-containing spacer with multiple nitrogen atoms and a carboxylic-acid coupling handle. Compared with a standard alpha-amino acid, this motif can alter linker length, basicity, conformational freedom and local polarity. It is therefore useful for medicinal-chemistry and peptide-engineering programs that intentionally move beyond canonical amino-acid side chains.

Applications in SPPS and Peptidomimetic Design

Fmoc-AEPipAc-OH.2HCl can be incorporated into Fmoc-SPPS and related stepwise coupling workflows. Reported uses of this building-block class include noncanonical peptide and peptide-mimetic synthesis, receptor-ligand optimization, linker engineering and construction of sequences requiring a piperazine-containing spacer. Depending on steric environment and resin accessibility, coupling conditions may require longer reaction times or stronger activation than routine amino-acid couplings.

Salt Form and Coupling Calculations

This material is supplied as a dihydrochloride salt. Researchers should use the molecular weight of the actual salt form for mmol calculations and account for the protonation state when selecting base equivalents. Treating the compound as the free base or a mono-HCl material can produce incorrect stoichiometry.

Downstream Application Scope

The protected building block is not intended as a direct in vitro or in vivo reagent. Peptides containing AEPipAc may subsequently be evaluated in binding, functional, permeability, stability or cellular assays after complete synthesis and characterization, depending on the final molecular design.

Product Documents

A Material Safety Data Sheet (MSDS) is available for this product to support laboratory handling, storage and safety assessment.

MSDS_Fmoc-AEPipAc-OH.2HCl_AS4033

Certificates of Analysis (COAs) are batch-specific. Please contact us to request the COA for your product, and we will provide it by email.

Frequently Asked Questions

What is the correct molecular formula?

For the dihydrochloride salt corresponding to CAS 204320-65-0 and MW 482.40, the formula is C₂₃H₂₉Cl₂N₃O₄.

Why use a piperazine-containing peptide building block?

Piperazine can introduce a basic heterocycle, additional polarity and a different spacer geometry compared with conventional amino-acid residues, making it useful in peptide and peptidomimetic optimization.

Can it be used in Fmoc-SPPS?

Yes. It is an Fmoc-protected building block designed for stepwise peptide synthesis, although difficult sequence contexts may require coupling optimization.

Related Technical Resources

Explore Specialty Peptide Building Blocks and our overview of Noncanonical Amino Acids in Peptide Drug Discovery.

Research Use Only.