Fmoc-3,4-Dichloro-D-Phenylalanine

Fmoc-3,4-Dichloro-D-Phenylalanine is an Fmoc-protected D-phenylalanine derivative in which the aromatic side chain bears two chlorine substituents at the 3- and 4-positions. The molecule combines an N-(9H-fluoren-9-ylmethoxycarbonyl) protecting group with a stereodefined D-amino acid center, providing a chiral peptide-building-block scaffold with increased hydrophobicity and halogen-controlled electronic character. The dichloro-substituted phenyl ring can participate in halogen-influenced conformational preferences and can serve as a handle for downstream derivatization or cross-coupling chemistry after peptide assembly or side-chain functional transformation. The Fmoc carbamate and the carboxylate functionality are engineered for compatibility with standard solid-phase or solution-phase peptide coupling workflows, supporting controlled deprotection to reveal the free amine for iterative chain elongation.

1. Peptide Synthesis

Fmoc-3,4-Dichloro-D-Phenylalanine is used in peptide synthesis as an Fmoc-protected D-amino acid building block for incorporating halogenated aromatic residues into peptide sequences. The Fmoc-protected N-terminus enables stepwise deprotection and coupling, while the D-configuration provides stereochemical control that can influence backbone conformation and protease stability profiles of the resulting peptides. The 3,4-dichloro substitution pattern on the side-chain phenyl ring introduces strong electron-withdrawing and steric effects that can modulate peptide folding, binding-site complementarity, and overall hydrophobic surface area. The resulting halogenated peptide products can be generated for structure-activity relationship studies, peptide analog libraries, and sequence optimization in chemical biology research.

2. Peptidomimetics And SAR

Fmoc-3,4-Dichloro-D-Phenylalanine is applied in peptidomimetic and SAR studies where halogenated aromatic side chains are incorporated to tune molecular recognition and physicochemical properties. The protected amino acid format supports rapid assembly of analog series by varying neighboring residues while holding the D-chiral center constant, enabling systematic evaluation of stereochemical and side-chain electronic effects. The dichloro-phenyl motif can be leveraged to create binding-site interactions influenced by halogen bonding and aromatic stacking, supporting rational design of peptide-like scaffolds with altered potency trends in screening campaigns. Downstream, assembled peptidomimetics can be further functionalized at the aromatic ring through synthetic transformations that retain the peptide-derived backbone architecture.

3. Side-Chain Functionalization

Fmoc-3,4-Dichloro-D-Phenylalanine is suitable for side-chain functionalization strategies that convert the dichloro aromatic ring into new substituents after peptide coupling or as part of protected-amino-acid intermediate planning. The 3,4-dichloro pattern provides two electrophilic aryl positions that can potentially undergo cross-coupling reactions to install aryl, heteroaryl, or other functional groups, while the D-configuration helps preserve stereochemical integrity of the amino acid-derived stereocenter. The Fmoc carbamate can be removed under standard deprotection conditions to generate a free amine for subsequent coupling steps, allowing iterative construction before or after aromatic diversification. The resulting functionalized amino acid or peptide derivatives can serve as chemical handles for creating targeted binding motifs, conjugation-ready scaffolds, and diversified libraries for medicinal chemistry and chemical biology workflows.

4. Chemical Biology Labeling

Fmoc-3,4-Dichloro-D-Phenylalanine is used in chemical biology labeling approaches where halogenated aromatic residues are incorporated to create detectable or affinity-tunable peptide constructs. The Fmoc-protected D-amino acid format supports controlled incorporation into peptides used for receptor-binding assays, pull-down probes, or affinity reagents, with the D-amino acid stereochemistry contributing to resistance against exopeptidases and altered degradation pathways. The dichloro-substituted phenyl ring can function as a stable hydrophobic and electron-modulating element that may improve retention in binding pockets and influence nonspecific adsorption during assay development. Downstream derivatives prepared from these labeled peptides can be adapted for biomolecule interaction mapping, probe optimization, and analytical method development.

5. Pharmaceutical Intermediate Preparation

Fmoc-3,4-Dichloro-D-Phenylalanine is relevant to pharmaceutical intermediate preparation and fine chemical synthesis where protected, stereodefined amino acid derivatives are required for manufacturing-grade peptide fragments or peptidomimetic intermediates. The Fmoc-protected amine and carboxyl functionality allow incorporation into protected peptide intermediates under reproducible coupling conditions, supporting scalable route design for halogenated aromatic motifs. The D-chiral center provides a stereochemically defined input that can be carried through downstream steps without racemization, which is important for consistent structure-property relationships in process chemistry. The dichloro aromatic side chain can further serve as a synthetic precursor for later-stage diversification, enabling controlled generation of substituted analogs used in medicinal chemistry programs and industrial peptide synthesis operations.

1. Cationic cell-penetrating peptides are potent furin inhibitors

2. Constitutive and inflammation-dependent antimicrobial peptides produced by epithelium are differentially processed and inactivated by the commensal Finegoldia magna and the pathogen Streptococcus pyogenes

3. Adipose tissue is a key organ for the beneficial effects of GLP-2 metabolic function

4. Multifunctional peptide-oligonucleotide conjugate promoted sensitive electrochemical biosensing of cardiac troponin I

5. Immune responses to homocitrulline-and citrulline-containing peptides in rheumatoid arthritis