H-alpha-Me-L-Trp-OH*0.5H2O is a free amino acid derivative of L-tryptophan bearing an additional alpha-methyl substituent, placing it in the class of substituted tryptophan analogues used for peptide and labeling studies. The molecule contains an amino group and a carboxylic acid (as the hydrated free acid), with the indole side chain of tryptophan retaining its aromatic functionality while the alpha-methyl substitution modifies steric and conformational properties relative to the parent amino acid. As a hydrated free amino acid, it can be employed in solution-phase or solid-phase peptide synthesis as an amino acid building block to introduce an alpha-methylated tryptophan residue, and it can also serve as a defined substrate for analytical method development or structure-activity studies involving tryptophan-containing peptides.
CAT No: CP25439
CAS No:16709-25-4
Synonyms/Alias:(S)-alpha-Methyltryptophan hemihydrate
Chemical Name:alpha-Methyl-L-tryptophane hemihydrate
H-alpha-Me-L-Trp-OH*0.5H2O is a hydrated form of an L-tryptophan derivative in which the alpha position bears a methyl substituent (H-alpha-Me), preserving the indole-containing side chain characteristic of tryptophan while introducing an additional stereogenic element at the alpha carbon. The molecule presents a free carboxylic acid (OH) and an amino acid backbone suitable for peptide coupling chemistry, while the indole nitrogen and aromatic indole ring provide distinct electronic and functional handles for derivatization and downstream scaffold modification. The alpha-methyl substitution can influence conformational preferences and steric approach during coupling, making it relevant for stereochemically controlled peptide analog design and for tuning side-chain/ backbone interactions in structure-based studies. The included half-equivalent water indicates a defined hydrate state that can affect handling, crystallization behavior, and reproducibility of synthetic intermediates used in protected amino acid synthesis and peptide building block preparation.
1. Peptide Synthesis
H-alpha-Me-L-Trp-OH*0.5H2O is applied in peptide synthesis workflows as an L-amino acid building block precursor for incorporating an alpha-methylated tryptophan residue into peptide chains. The free carboxylic acid and amino acid backbone enable conversion to activated coupling forms or protected derivatives that participate in amide bond formation, while the indole side chain can be managed through indole-compatible protecting-group strategies during N- and C-terminal assembly. Alpha-methyl substitution can be used to generate peptide analogs with altered backbone conformations and steric profiles, supporting the construction of constrained or protease-resistant sequences. The hydrate form can be leveraged for consistent intermediate preparation when scaling peptide building block production for research-grade and fine chemical manufacturing.
2. Unnatural Amino Acid Incorporation
H-alpha-Me-L-Trp-OH*0.5H2O supports unnatural amino acid incorporation studies in chemical biology and peptide engineering by providing an L-tryptophan analog with an alpha-methyl stereochemical feature. The indole aromatic system remains available for receptor-binding and aromatic interaction mapping, whereas the alpha-methyl center can modulate local geometry and influence how the residue is recognized within peptide scaffolds. Derivatization to N-protected or side-chain-protected forms can be employed to maintain orthogonal protection during iterative peptide construction, followed by controlled deprotection to reveal the indole functionality for subsequent functionalization. Downstream, the resulting peptide analogs can be used to generate structure-activity relationship panels and to probe how backbone methylation affects molecular recognition and stability.
3. Bioconjugation Chemistry
H-alpha-Me-L-Trp-OH*0.5H2O is suitable for bioconjugation and biomolecule modification routes where tryptophan-derived aromatic handles and peptide-compatible functional groups enable controlled attachment strategies. The amino acid backbone can be transformed into coupling-ready derivatives that allow incorporation into peptide tags, affinity ligands, or linker-containing constructs used for labeling and analytical workflows. The indole moiety can participate in electrophilic substitution or oxidative transformations under appropriate conditions, enabling formation of conjugates that retain aromatic identity while introducing new functional groups for downstream immobilization or detection. Hydrate-controlled handling can support reproducible intermediate formation when preparing amino acid-derived conjugation building blocks for research-grade reagent manufacturing.
4. Structure-Activity Relationship Studies
H-alpha-Me-L-Trp-OH*0.5H2O is utilized in structure-activity relationship studies and molecular design efforts to generate residue-level variants that isolate the impact of alpha-methylation on tryptophan-containing scaffolds. The combination of a stereodefined alpha-methyl center and the indole side chain enables systematic variation of steric bulk and backbone conformation while maintaining the aromatic pharmacophore. Protection-group strategies for the amino and carboxyl functions can be aligned with peptide coupling chemistry to produce analog series with consistent termini and controlled side-chain exposure. The resulting analogs can serve as chemical probes for mapping binding modes, conformational preferences, and aromatic interaction contributions in peptide-based molecular recognition studies.
5. Pharmaceutical Intermediate Preparation
H-alpha-Me-L-Trp-OH*0.5H2O functions as a chiral amino acid intermediate for fine chemical synthesis and pharmaceutical intermediate preparation where stereochemically defined tryptophan derivatives are required for downstream medicinal chemistry. The free carboxylic acid supports conversion to activated ester or acid chloride equivalents, while the amino acid functionality can be protected to enable selective transformations on the indole ring or on the alpha-methylated backbone. Indole-containing intermediates can be routed through orthogonal protection and deprotection sequences to deliver defined peptide building blocks, linker fragments, or peptidomimetic precursors used in manufacturing-oriented synthetic routes. The hydrate state can be incorporated into process design to support reproducible solid-state behavior and intermediate handling during scale-up of amino acid derivative production.
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