Fmoc-L-tert.leucine is an Fmoc-protected amino acid derivative featuring an L-configured α-amino acid backbone and a tert-leucine side chain that contains a branched, hydrophobic tert-alkyl substituent. The molecule bears a free carboxyl functionality and an N-(9H-fluoren-9-ylmethoxycarbonyl) (Fmoc) protecting group on the amino group, which modulates chemoselectivity during peptide coupling and suppresses undesired amine reactivity. In peptide chemistry, it is employed as a protected building block for introducing a sterically demanding, hydrophobic residue analogue into peptides during stepwise synthesis and for preparing amino acid derivatives for structure-activity and labeling studies.
CAT No: CP07905
CAS No:132684-60-7
Synonyms/Alias:132684-60-7;Fmoc-L-tert-leucine;(S)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)amino)-3,3-dimethylbutanoicacid;Fmoc-Tle-OH;Fmoc-tBu-Gly-OH;fmoc-d-alpha-t-butylglycine;(2S)-2-(9H-fluoren-9-ylmethoxycarbonylamino)-3,3-dimethyl-butanoicacid;Fmoc-L-tertleucine;Fmoc-L-tert.leucine;AmbotzFAA1748;AC1LJQP0;Fmoc-alpha-t-butyl-Gly-OH;L-Valine,N-[(9H-fluoren-9-ylmethoxy)carbonyl]-3-methyl-;47524_ALDRICH;SCHEMBL1253102;47524_FLUKA;CTK4B8037;MolPort-003-725-627;VZOHGJIGTNUNNC-GOSISDBHSA-N;ZINC4521494;ANW-56703;AKOS010367902;AM82576;CF-1280;RTR-004461
Fmoc-L-tert.leucine is an N-(9H-fluoren-9-ylmethoxycarbonyl) protected L-amino acid in which the side chain is a tert-leucine motif bearing a highly substituted aliphatic carbon framework. The molecule contains an Fmoc carbamate on the amino group, a free carboxylic acid for standard peptide coupling chemistry, and a single stereogenic center at the alpha carbon consistent with L-configuration. The bulky, branched side chain influences conformational preferences in peptide backbones and can modulate steric access during synthesis and downstream functionalization. The Fmoc group provides base-labile protection compatible with solid-phase peptide synthesis, while the carboxyl functionality enables conversion to activated esters or coupling-ready derivatives for controlled chain elongation.
1. Peptide Synthesis
Fmoc-L-tert.leucine is used in peptide building block preparation for both solution-phase and solid-phase peptide synthesis, where the Fmoc-protected amine and free carboxylic acid are directly compatible with common peptide coupling strategies. The tert-leucine side chain's steric bulk can be leveraged to probe how branched hydrophobic residues affect folding, aggregation propensity, and local backbone geometry in peptide analogs. Fmoc deprotection under basic conditions regenerates the reactive amine for sequential coupling, supporting iterative construction of protected peptide intermediates. Downstream, the incorporated residue can serve as a structural element in peptide libraries, enabling systematic derivatization of hydrophobic patches for structure-activity relationship studies.
2. Peptidomimetics
Fmoc-L-tert.leucine supports peptidomimetic construction by introducing a branched, hydrophobic side chain that can mimic steric and lipophilic features of natural amino acid patterns in biomolecular recognition motifs. The Fmoc-protected amino acid format facilitates incorporation into synthetic scaffolds while maintaining stereochemical integrity at the alpha center. The carboxylic acid enables formation of amide linkages during scaffold assembly, allowing subsequent diversification through side-chain oxidation, alkylation, or crosslinking routes when compatible with the protecting-group scheme. The resulting peptidomimetic intermediates can be advanced into fragment-based molecular design workflows and SAR studies focused on conformational control.
3. Chemical Biology
Fmoc-L-tert.leucine is applied in chemical biology research where amino acid derivatization and controlled peptide assembly are used to generate defined biomolecule-modifying reagents. The Fmoc-protected amine enables stepwise synthesis of peptide conjugates bearing tert-leucine residues that can tune hydrophobic interactions and influence membrane association or binding-site accessibility in assay formats. The free carboxyl group allows conversion into activated coupling derivatives for attachment to linkers, affinity handles, or reporter-bearing fragments after peptide assembly. The stereochemically defined L-center and robust amide connectivity help maintain structural fidelity in downstream biochemical investigation of molecular recognition processes.
4. Process Chemistry Intermediate
Fmoc-L-tert.leucine is suitable for process chemistry intermediate preparation in industrial fine chemical synthesis due to its stable Fmoc carbamate protection and standardized amino acid functional group set. The presence of a single, well-defined alpha-amino stereocenter and a carboxylic acid supports reproducible conversion to coupling-ready forms under controlled manufacturing conditions. The Fmoc group can be removed in a predictable manner during peptide chain assembly, aligning with scalable solid-phase or automated peptide manufacturing workflows. The tert-leucine side chain's steric character can be exploited to produce peptide intermediates with targeted solubility and handling properties that affect downstream purification and formulation development.
5. Pharmaceutical Manufacturing
Fmoc-L-tert.leucine is utilized in pharmaceutical manufacturing contexts for the preparation of protected peptide intermediates used in the synthesis of peptide-based drug candidates and research-grade peptide materials. The Fmoc-protected amine enables sequential coupling on resin or in controlled solution sequences, while the carboxylic acid functionality supports formation of stable amide bonds in the target sequence. The bulky, branched side chain can contribute to conformational constraints that influence peptide stability and resistance to proteolytic cleavage during manufacturing-scale synthesis planning. The resulting protected amino acid incorporation supports consistent downstream processing into final peptide products or peptide fragments for analytical characterization and process development.
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