Fmoc-beta-Ala(SO3H)-OH is a protected β-alanine derivative bearing a sulfonic acid side chain, where the α-amino group is masked as an Fmoc carbamate and the carboxyl group remains as a free carboxylic acid. The molecule contains both an Fmoc-protected α-amino functionality and a pendant -SO3H group, with the β-amino acid backbone retaining the β-alanine topology for incorporation into peptide frameworks. It is used as a building block in stepwise peptide synthesis and related amino acid coupling workflows, where the sulfonate functionality provides a strongly anionic handle for structure-activity studies, solubility tuning, and analytical labeling of peptide or biomolecular constructs.
CAT No: CP25104
CAS No:1005412-03-2
Chemical Name:N-(9-Fluorenylmethyloxycarbonyl)-alpha-sulfo-beta-Alanine, (SR)-3-(9-Fluorenylmethyloxycarbonylamino)-2-sulfo-propanoic acid
Fmoc-beta-Ala(SO3H)-OH is an Fmoc-protected β-alanine derivative bearing a sulfonic acid functionality on the side chain, combining a chiral amino acid backbone with a strongly acidic, highly polar sulfonate group. The molecule contains an N-(9H-fluoren-9-ylmethoxycarbonyl) protecting group on the β-amino terminus, a free carboxylic acid for C-terminal compatibility, and an anionic sulfonate motif that can participate in ionic interactions and salt formation under peptide-synthesis and post-synthetic conditions. The presence of a sulfonic acid group influences solubility, coupling microenvironment, and downstream transformations such as ion-pairing, desulfonylation avoidance, or controlled salt-state switching. As a protected amino acid building block, it is designed to be incorporated into peptide sequences while preserving the sulfonate functionality for biochemical recognition, analytical readouts, or material-relevant charge density.
1. Peptide Synthesis
Fmoc-beta-Ala(SO3H)-OH is used in peptide building-block workflows where Fmoc deprotection and subsequent amide-bond formation enable stepwise solid-phase peptide synthesis of sulfonated β-alanine-containing sequences. The Fmoc-protected amine supports standard peptide coupling chemistry, while the free carboxylic acid and the sulfonic acid side chain provide defined C-terminal reactivity and a persistent, strongly polar functional handle. The sulfonate group can remain intact during coupling and can be carried through purification as a salt or zwitterionic form, supporting peptide analog construction for charge-dependent studies. Downstream, the resulting peptides can be applied as reference standards, mechanistic probes, or scaffold components in peptide chemistry and peptidomimetic design.
2. Chemical Biology
Fmoc-beta-Ala(SO3H)-OH is suitable for chemical biology applications that require incorporation of a stable, anionic sulfonate motif into peptide or peptide-like ligands. The sulfonic acid functionality enables electrostatic interactions with positively charged residues, metal ions, or receptor binding pockets, while the β-alanine spacer can modulate distance and local conformational effects. The Fmoc-protected backbone supports controlled assembly of sulfonated motifs into larger constructs for mapping binding determinants, studying charge effects, or generating functional probes for molecular recognition. The resulting sulfonated peptides and conjugates can be used to interrogate biomolecular interactions and to support structure-function investigations where persistent negative charge is a key design element.
3. Bioconjugation Chemistry
Fmoc-beta-Ala(SO3H)-OH can serve as a precursor for bioconjugation strategies where a sulfonate-bearing amino acid segment is introduced into targeting peptides or linker architectures. The sulfonic acid group provides a durable, water-compatible anionic handle that can influence conjugate solubility, reduce aggregation, and enable ionic pairing with cationic partners during conjugation or formulation. The Fmoc-protected amine allows the compound to be incorporated into conjugatable peptide frameworks, after which the sulfonate functionality can remain available for subsequent coupling to biomolecules or for constructing multivalent charge patterns. The resulting sulfonated conjugates can be employed in labeling, affinity reagent preparation, and downstream analytical or separation workflows that benefit from strong ionic character.
4. Analytical Research Standards
Fmoc-beta-Ala(SO3H)-OH is applicable to analytical research where defined sulfonated amino acid and peptide fragments are needed as reference materials for method development and characterization. The combination of an Fmoc-protected backbone and a sulfonic acid side chain supports generation of characteristic fragmentation patterns and retention behavior in chromatographic and mass spectrometric analyses of sulfonated peptides. The carboxylic acid and sulfonate groups provide predictable ionization properties, which can assist in establishing calibration strategies for sulfonate-containing species. The compound can also be used to prepare internal standards or synthetic comparators that support accurate identification and quantification of sulfonated building blocks and peptide derivatives.
5. Process Chemistry Intermediate
Fmoc-beta-Ala(SO3H)-OH is relevant to process chemistry and fine chemical synthesis as an amino acid derivative intermediate that integrates an orthogonally removable N-protecting group with a persistent sulfonate functionality. The Fmoc group supports scalable protection/deprotection logic compatible with industrial peptide-manufacturing workflows, while the sulfonic acid moiety can be maintained through intermediate handling to preserve downstream functionality. The molecule's defined functional group set, including the carboxylic acid for coupling and the sulfonate for ionic specification, can facilitate route design for producing sulfonated peptide building blocks, peptidomimetic fragments, or charged linker units. The resulting intermediate utility extends to specialty chemical production where controlled incorporation of anionic motifs is required for consistent product performance in subsequent synthesis steps.
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