L-methionine isopropyl ester hydrochloride is a methionine-derived amino acid ester in which the carboxyl group of L-methionine is converted to an isopropyl ester while the amino functionality remains present and is associated with hydrochloride to form a salt. The molecule contains a thioether-containing side chain characteristic of methionine, along with an ester carbonyl and an amino group, with stereochemistry indicated by the "L-" designation for the amino acid center. In peptide and amino-acid derivative synthesis, amino acid esters such as this one are used as protected carboxyl equivalents or substrates for stepwise transformations, and the hydrochloride salt form supports handling and controlled reactivity during chemical labeling, conjugation, or analytical derivatization workflows.
CAT No: CP01522
CAS No:85391-05-5
Synonyms/Alias:85391-05-5;H-MET-OIPRHCL;(S)-Isopropyl2-amino-4-(methylthio)butanoatehydrochloride;L-methionineisopropylesterhydrochloride;H-Met-OiPr??HCl;IsopropylL-methionateHCl;SCHEMBL6775565;CTK7B5619;MolPort-003-981-646;ONXXRAMAPIOLSS-FJXQXJEOSA-N;IsopropylL-methionatehydrochloride;EINECS286-758-5;3251AC;AKOS015849589;AM82151;methionineisopropylesterhydrochloride;AK111193;KB-53323;L-METHIONINEISOPROPYLESTERHYDROCHLORIDE;H-Met-OiPrinvertedexclamationmarkcurrencyHCl;A841317;propan-2-yl(2S)-2-azanyl-4-methylsulfanyl-butanoatehydrochloride;(2S)-2-amino-4-(methylthio)butanoicacidpropan-2-ylesterhydrochloride
L-methionine isopropyl ester hydrochloride is the hydrochloride salt form of the L-methionine side-chain amino acid ester, featuring an L-configured stereocenter at the alpha carbon and an isopropyl ester at the carboxyl position. The molecule retains the thioether side chain characteristic of methionine, which can participate in oxidation-state dependent transformations during downstream synthesis, while the ester functionality supports controlled peptide coupling or conversion into activated carboxyl derivatives. The hydrochloride counterion protonates the amino group, enabling storage and handling as a stable, amino-protected salt equivalent that can be cleanly converted into reactive forms under standard amino acid derivative conditions. The combination of chiral amino acid architecture and ester-based carboxyl reactivity makes this compound a practical intermediate for protected amino acid synthesis, chiral building block preparation, and subsequent functional group interconversions.
1. Protected Amino Acid Chemistry
L-methionine isopropyl ester hydrochloride is used in protected amino acid synthesis workflows where an amino acid ester serves as a controllable precursor to N-protected and/or carboxyl-activated derivatives. The L-amino acid stereochemistry and the esterified carboxyl group enable conversion into peptide-ready formats while maintaining the methionine side chain thioether for later selective oxidation or functionalization steps. Hydrochloride salt formation provides a convenient protonated amine state that can be deprotonated and re-protected as needed for peptide coupling compatibility. Downstream formation of N-protected methionine derivatives and activated carboxyl intermediates supports both research-grade peptide assembly and process-oriented intermediate preparation.
2. Peptide Coupling Building Blocks
L-methionine isopropyl ester hydrochloride is suitable for peptide synthesis development where amino acid esters are converted into carboxyl-activated species for amide bond formation. The alpha-amino functionality, once appropriately neutralized and protected, can participate in standard peptide coupling strategies while the isopropyl ester provides a handle for generating activated carboxyl derivatives or for transesterification to match coupling requirements. The methionine thioether side chain remains intact during coupling steps, allowing incorporation into peptide sequences that later undergo side-chain oxidation or conjugation chemistry. The resulting methionine-containing peptide building blocks and analogs support routine peptide construction and chiral sequence design in synthetic organic chemistry and biochemical research.
3. Side-Chain Functionalization
L-methionine isopropyl ester hydrochloride is applied in side-chain functionalization programs that exploit the methionine thioether for controlled chemical modification. The thioether can be transformed into higher oxidation-state functionalities under conditions compatible with peptide or protected amino acid intermediates, enabling access to sulfoxide or sulfone-containing analogs that alter polarity and oxidation sensitivity. The ester and amino salt framework supports staged protection/deprotection so that functional group transformations can be scheduled relative to N- and C-terminal manipulations. Downstream products include functionalized methionine derivatives and peptidomimetic scaffolds used to probe chemical recognition, stability, and reactivity patterns in amino acid chemistry.
4. Chemical Biology Labeling
L-methionine isopropyl ester hydrochloride can serve as a chiral starting material for chemical biology workflows that require methionine-based building blocks with tunable reactivity. The preserved L-configuration and side-chain thioether structure support incorporation into peptide fragments that can be further modified for labeling strategies, including oxidation-state dependent handles for conjugation-compatible derivatives. Ester-to-amide or ester-to-activated acid conversions enable construction of peptide conjugates while maintaining stereochemical fidelity at the alpha carbon. The resulting labeled or derivatized methionine-containing molecules can be used for biochemical research intermediate generation, molecular recognition studies, and analytical method development.
5. Process Chemistry Intermediate
L-methionine isopropyl ester hydrochloride is relevant to process chemistry intermediate preparation where amino acid ester salts provide practical control over handling, solubility, and downstream conversion to activated carboxyl forms. The hydrochloride salt state supports reproducible amine protonation control for subsequent protection and coupling-ready transformations in manufacturing-style synthesis planning. The isopropyl ester offers a defined carboxyl functional group that can be converted to alternative ester types or activated acids under scalable conditions, while the methionine thioether can be carried through steps with scheduled oxidation or functionalization. The compound therefore functions as a chiral, process-compatible precursor for fine chemical synthesis routes that generate protected amino acids, peptide building blocks, and methionine-based intermediates for industrial peptide and specialty chemical production.
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