4-Hydroxy Isoleucine - ≥95% , CAS No.781658-23-9

CAS: 781658-23-9 Cat. No.: H134438 Formula: C₆H₁₃NO₃ Peso molecolare: 147.17 Numero EC: 631-182-5

GRADE & PURITY ≥95%

Synonyms

4-?Hydroxy-?L-?isoleucine | 4-HYDROXY-L-ISOLEUCINE | (2S,3R)-2-amino-4-hydroxy-3-methylpentanoic acid | CCG-266183 | 4-ydroxy--soleucine | 4-Hydroxyisoleucine, United States Pharmacopeia (USP) Reference Standard | Rel-(2S,3R)-2-amino-4-hydroxy-3-methylpen

Storage

Store at 2-8°C

Shipped In

Wet ice

Specifications

Sinonimi

4-?Hydroxy-?L-?isoleucine | 4-HYDROXY-L-ISOLEUCINE | (2S,3R)-2-amino-4-hydroxy-3-methylpentanoic acid | CCG-266183 | 4-ydroxy--soleucine | 4-Hydroxyisoleucine, United States Pharmacopeia (USP) Reference Standard | Rel-(2S,3R)-2-amino-4-hydroxy-3-methylpen

Specifiche e purezza

≥95%

Meccanismi biochimici e fisiologici

A special amino acid extracted from the seeds of fenugreek, which has never been found in mammalian tissues, shows proinsulin activity; Effects on insulin secretion, plant-based treatment of metabolic syndrome.

Condizioni di conservazione di stoccaggio

Store at 2-8°C

Spedito in

Wet ice

Questo prodotto richiede spedizione a catena fredda. I servizi di terra e altri servizi economici non sono disponibili.

Purezza

≥95%

Nomi e identificatori

• Pubchem Sid: 488193530
• Pubchem Sid Url: https://pubchem.ncbi.nlm.nih.gov/substance/488193530
• Sorrisi canonici: CC(C(C)O)C(C(=O)O)N
• IUPAC Name: (2S,3R)-2-amino-4-hydroxy-3-methylpentanoic acid
• InChIKey: OSCCDBFHNMXNME-DSDZBIDZSA-N
• INCHI: 1S/C6H13NO3/c1-3(4(2)8)5(7)6(9)10/h3-5,8H,7H2,1-2H3,(H,9,10)/t3-,4?,5-/m0/s1
• Isomeri SMILES: C[C@H]([C@@H](C(=O)O)N)C(C)O
• WGK Germania: 3
• Peso molecolare: 147.17
• Reaxy-Rn: 11036006
• Reaxys-RN_link_address: https://www.reaxys.com/reaxys/secured/hopinto.do?context=S&query=IDE.XRN=11036006&ln=

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Organic acids and derivatives
    • Classe Carboxylic acids and derivatives
      • Subclass Amino acids, peptides, and analogues
        • Level5 Amino acids and derivatives
          • Level6 Alpha amino acids and derivatives
            • Level7 Isoleucine and derivatives

• Kingdom: Organic compounds
• Superclass: Organic acids and derivatives
• Classe: Carboxylic acids and derivatives
• Subclass: Amino acids, peptides, and analogues
• Intermediate Tree Nodes: Amino acids and derivatives - Alpha amino acids and derivatives
• Direct Parent: Isoleucine and derivatives
• Alternative Parents: L-alpha-amino acids Short-chain hydroxy acids and derivatives Methyl-branched fatty acids Hydroxy fatty acids 1,3-aminoalcohols Secondary alcohols Amino acids Monocarboxylic acids and derivatives Carboxylic acids Organopnictogen compounds Organic oxides Monoalkylamines Hydrocarbon derivatives Carbonyl compounds
• Molecular Framework: Aliphatic acyclic compounds
• Substituents: Isoleucine or derivatives - Alpha-amino acid - L-alpha-amino acid - Branched fatty acid - Hydroxy fatty acid - Methyl-branched fatty acid - Short-chain hydroxy acid - Fatty acyl - Fatty acid - 1,3-aminoalcohol - Amino acid - Secondary alcohol - Carboxylic acid - Monocarboxylic acid or derivatives - Organic nitrogen compound - Organooxygen compound - Organonitrogen compound - Primary amine - Primary aliphatic amine - Hydrocarbon derivative - Organic oxide - Carbonyl group - Organopnictogen compound - Amine - Organic oxygen compound - Alcohol - Aliphatic acyclic compound
• Descrizione: This compound belongs to the class of organic compounds known as isoleucine and derivatives. These are compounds containing isoleucine or a derivative thereof resulting from reaction of isoleucine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom.
• External Descriptors: Not available

Data sources

1. Djoumbou Feunang Y, Eisner R, Knox C, Chepelev L, Hastings J, Owen G, Fahy E, Steinbeck C, Subramanian S, Bolton E, Greiner R, and Wishart DS. ClassyFire: Automated Chemical Classification With A Comprehensive, Computable Taxonomy. Journal of Cheminformatics, 2016, 8:61.

DOI: 10.1186/s13321-016-0174-y

Meccanismi d'azione

Proprietà chimiche e fisiche

• Solubilità: soluble in water
• Punto di infiammabilità (°F): 296.6 °F
• Punto di infiammabilità (°C): 147 °C
• Peso molecolare: 147.170 g/mol
• XLogP3: -2.800
• Hydrogen Bond Donor Count: 3
• Hydrogen Bond Acceptor Count: 4
• Rotatable Bond Count: 3
• Exact Mass: 147.09 Da
• Monoisotopic Mass: 147.09 Da
• Topological Polar Surface Area: 83.600 Ų
• Heavy Atom Count: 10
• Formal Charge: 0
• Complexity: 126.000
• Isotope Atom Count: 0
• Defined Atom Stereocenter Count: 2
• Undefined Atom Stereocenter Count: 1
• Defined Bond Stereocenter Count: 0
• Undefined Bond Stereocenter Count: 0
• The total count of all stereochemical bonds: 0
• Covalently-Bonded Unit Count: 1

Riferimenti

1. Emmanuel Osei Nkansah, Yunzhu Lan, Hui Zhang, Binbin Xu, Qiaodan Li, Mohammad Ishraq Zafar, Jian Xu.  (2025)  Potential role of 4-hydroxyisoleucine in enhancing fertility in male mice with diet-induced obesity.  Frontiers in Endocrinology,      [PMID:40917356] [10.3389/fendo.2025.1561543]

Application Protocols

No vendor‑validated application protocols are provided in the Product Data for this item. The following general procedures are offered as nonbinding guidance for common laboratory uses of amino acids; adapt to your system and consult the primary literature.

• Preparation of aqueous stock solutions
  • Weigh appropriate amount to achieve 100 mM in water or buffer. Adjust pH to 1–2 (HCl) or 9–10 (NaOH) if needed to fully dissolve, then readjust to target pH. Filter through 0.22 µm for sterile work. Store aliquots at 2–8 °C for short term.
• RP‑HPLC quantitation (example conditions)
  • Column: C18, 150 × 4.6 mm, 3–5 µm. Mobile phase A: water + 0.1% formic acid; B: acetonitrile + 0.1% formic acid. Gradient: 2%→20% B over 15 min. Detection: UV after precolumn derivatization (e.g., OPA/FMOC) or MS.
• Chiral analysis (illustrative)
  • Derivatize with Marfey’s reagent (FDAA) at pH ~8–9, 40–60 °C for 30–60 min; analyze by RP‑HPLC to separate diastereomers representing enantiomers/diastereomers.
• Peptide coupling (small scale)
  • Dissolve N‑protected, C‑protected derivative in DMF; add HATU (1.1 equiv) and DIPEA (2 equiv) at 0 °C; add amine partner; stir 1–2 h, monitor by LC‑MS; quench and purify.

Note: These are example workflows. Validate all conditions, especially pH and solvent content, for compatibility with your downstream application. For regulated or critical uses, develop and document formal SOPs.

Biological Roles

• General context (literature)
  • 4‑Hydroxy isoleucine is a non‑proteinogenic amino acid reported in seeds of Trigonella foenum‑graecum (fenugreek). It is structurally related to the branched‑chain amino acids (BCAAs) and bears a γ‑hydroxy substituent.
  • In biochemical studies, hydroxylated BCAAs serve as probes for transamination, deamination, and β‑oxidation‑adjacent pathways, as well as substrate/ligand analogs for amino acid transporters.
• Physicochemical/biochemical properties
  • Zwitterionic at neutral pH; participates in hydrogen bonding via both the α‑amino/α‑carboxylate and the secondary alcohol. These features influence transporter affinity and enzyme recognition in vitro.
  • The γ‑hydroxy group can engage in intra/intermolecular H‑bonds, affecting peptide secondary structure when incorporated into synthetic peptides.
• Research applications (nonclinical)
  • Used as a reference standard in metabolomics of plant matrices and as a model compound to study structure–activity relationships of BCAA derivatives.
  • Investigations in cell‑free and cellular systems have explored its impact on carbohydrate/fuel metabolism signaling pathways; any such findings are context‑dependent and research‑only. No claims are made here regarding therapeutic or clinical performance.
• Handling in biological experiments
  • Prepare isotonic, pH‑controlled aqueous solutions to avoid osmotic or pH artifacts.
  • Filter‑sterilize (0.22 µm) for cell culture compatibility; confirm endotoxin/bioburden requirements with your QA if applicable.

Note: Specific biological properties of this catalog item (e.g., enantiomeric form, salt state) should be verified against the CoA, as these materially influence transport and enzyme interactions.

Buffer Applications

4‑Hydroxy isoleucine is not a conventional buffering agent. As an α‑amino acid, it exhibits two principal titratable groups (carboxyl and ammonium), but it is typically used as a substrate, standard, or building block rather than as a pH buffer.

• Practical guidance
  • If used in buffered solutions, select an external buffer appropriate to your target pH (e.g., phosphate pH 6–8, acetate pH 4–5.5, Tris pH 7–9). Keep amino acid concentration independent of buffer capacity to avoid pH drift.
  • The amino acid’s zwitterionic form around neutral pH contributes minimally to buffering compared with classical buffers.
• Recipes (illustrative; buffer components only)
  • Phosphate buffer (50 mM, pH 7.4): Na2HPO4/NaH2PO4 in water; add the weighed amino acid and adjust pH if needed.
  • Acetate buffer (50 mM, pH 4.5): Sodium acetate/acetic acid; dissolve the amino acid last to ensure complete dissolution.
• Compatibility notes
  • Avoid strong base during prolonged storage; hydroxy‑amino acids may undergo undesirable side reactions at high pH over time.
  • For ion‑exchange separations, the amphoteric nature can be exploited, but the amino acid itself is not the buffering species.

Green Alternatives

Greener strategies for working with 4‑hydroxy isoleucine focus on solvent selection, coupling chemistry, and protection/deprotection conditions.

• Solvent and media choices
  • Prefer water or water‑rich media for dissolution and biocatalysis; consider buffer‑compatible coupling agents (e.g., EDC with NHS) that operate in aqueous systems.
  • Replace DMF/NMP in peptide couplings with greener alternatives like 2‑MeTHF, CPME, or propylene carbonate when compatible with solubility and reagents. Co‑solvent systems (water/EtOH or water/2‑MeTHF) can be effective.
• Coupling chemistry
  • Use carbodiimide (EDC·HCl) in water or aqueous alcohols to minimize dipolar aprotic usage; HOAt/HOBt alternatives with improved safety (e.g., OxymaPure) reduce explosive hazard.
  • Enzymatic ligation (proteases, ligases) in aqueous media can install peptide bonds under mild, waste‑minimizing conditions where sequence allows.
• Protection/deprotection
  • Choose protecting groups removable under mild, atom‑economical conditions (e.g., carbonate‑type for OH, avoiding heavy‑metal catalysis). Hydrogenolysis with catalytic hydrogen (EtOH/water) can replace harsher reagents for benzyl groups.
• Workup and purification
  • Favor crystallization or aqueous phase separations over silica chromatography. If chromatography is required, minimize chlorinated solvents; use EtOAc/MeOH or EtOAc/EtOH mixtures.

Comparison (general guidance)

• Conventional: DMF/HATU, DCM workups, HOBt additives; high E‑factor.
• Greener: Water/EtOH media, EDC/Oxyma or enzymatic coupling, reduced dipolar aprotics; lower solvent hazard and waste.

Trade‑offs: Greener media may reduce substrate solubility and coupling rates; small amounts of DMSO/EtOH as co‑solvents often restore performance while keeping hazard lower.

Pharmaceutical Uses

No pharmacopeial status or excipient grade is specified for this item; refer to the CoA/Spec Sheet for any regulatory designations. The information below addresses general formulation roles of amino acid derivatives in research and development settings without implying therapeutic use.

• Potential roles (R&D context)
  • Excipients in research formulations: Amino acids can act as stabilizers, tonicity adjusters, or pH co‑modulators in experimental injectables or lyophilized cakes; suitability of 4‑hydroxy isoleucine must be established empirically.
  • Enabling salts: Formation of well‑defined salts (e.g., hydrochlorides, sodium carboxylates) can tune solubility and crystallinity for preformulation studies.
  • Protic coformers: The carboxyl and amino functionalities may support cocrystal screening as coformers in solid‑state R&D.
• Considerations
  • Safety/tox profile: Use is limited to research use only per Product Data; no clinical claims are made. If advancing to regulated work, establish full impurity, residual solvent, and elemental impurity profiles.
  • Solid‑state behavior: Hygroscopicity, polymorphism, and potential for lactone formation under dehydrating conditions should be assessed by PXRD/DSC/TGA.
  • Compatibility: Evaluate interactions with reducing sugars (Maillard pathways) and reactive carbonyl excipients. Control pH to limit degradation.
• Analytical control
  • Assay by HPLC with pre‑ or post‑column derivatization for UV detection, or LC‑MS/MS for direct quantification.
  • Chiral integrity must be monitored if enantiopure material is required (chiral HPLC or derivatization methods).

Note: No pharmacopoeial monograph or excipient designation is claimed for this catalog item.

Physical Properties

Item-specific values are not provided in the Product Data; consult the CoA/Spec Sheet for definitive specifications.

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.
• Physical constants (literature/general; for reference only, not item specs)
  • Molecular formula (free amino acid): C6H13NO3 (literature)
  • Molecular weight: ~147.17 g/mol (literature)
  • Acid–base behavior: Typical of α‑amino acids; pKa values depend on stereochemistry/ionic strength. Representative literature values for related hydroxy‑branched amino acids: pKa1 (CO2H) ~2.1–2.5; pKa2 (NH3+) ~9.0–9.6; side‑chain OH pKa >>12 (poorly acidic). Verify experimentally for this item.
  • Solubility: Amino acid zwitterions are generally highly soluble in water and poorly soluble in most aprotic organics; solubility increases in alcohol–water mixtures and at extreme pH. Quantitative solubility for this item is not specified.
  • Partitioning: Expected low logP and strong polarity/zwitterionic character at neutral pH (literature trend for α‑amino acids).
  • Optical rotation: Dependent on isomeric composition and solvent; not specified for this item.
  • Melting/decomposition: Many amino acids exhibit high melting points with decomposition; specific MP for this item is not specified.
• Spectroscopic notes (general)
  • IR: Broad O–H/N–H stretch (3200–3500 cm−1), C=O (carboxyl) ~1710–1730 cm−1 (acid) or ~1580–1610/1400–1450 cm−1 (carboxylate), C–O (alcohol) ~1040–1100 cm−1.
  • NMR: Distinct α‑CH (~3.7–4.2 ppm, 1H), side‑chain methines/methylenes 0.8–2.5 ppm; OH/NH exchangeable signals solvent‑ and pH‑dependent.

Quality and Grades

• Item-specific grade/purity: Not specified for this item; refer to CoA/Spec Sheet.
• Typical quality considerations for amino acid building blocks
  • Chemical purity: For synthetic and biochemical applications, assay by quantitative NMR or HPLC is common. Reported impurities may include related stereoisomers, lactones, dehydration products, and residual inorganic salts from isolation.
  • Optical purity: Enantiomeric/diastereomeric excess is critical. Verification by chiral HPLC or Marfey’s/OPA derivatization methods is routine. If your work is stereosensitive (e.g., peptide synthesis), confirm ee/de with the CoA.
  • Inorganic content: Ash or residual metal content is occasionally reported for biogenic amino acids. If trace metals matter (e.g., catalysis inhibition), request ICP data.
  • Water content: Karl Fischer moisture can influence weighing accuracy and coupling efficiency. When critical, request KF data and dry under vacuum before use.
  • Microbial/bioburden: For cell‑related research, vendors may provide bioburden or endotoxin data; none are specified here.
• Grade definitions (general)
  • Research grade: Suitable for most synthetic/analytical uses; UV/background and particle control are general laboratory standards.
  • BioUltra/BioXtra/USP/JP/EP grades (if applicable): Imply tighter controls on bioburden, heavy metals, and assay. Not specified for this item.
• Stabilizers/additives
  • Amino acids typically ship neat without stabilizers. Any additives would be declared on the CoA; none are specified for this item.

Reaction and Applications

As a hydroxylated, branched‑chain amino acid, 4‑hydroxy isoleucine serves as a versatile chiral building block and probe in biochemical and synthetic settings.

• Research applications (general)
  • Biochemistry/nutrition: Standard for quantification of fenugreek secondary amino acids; tracer in metabolic studies of branched‑chain amino acid pathways (in vitro/in vivo models—nonclinical research only).
  • Analytical standards: Calibration for LC‑MS/LC‑UV methods profiling plant‑derived amino acids and for stability studies of hydroxy‑amino acids.
• Synthetic chemistry
  • Peptide incorporation: Introduces a γ‑hydroxy, β‑branched residue to modulate peptide conformation and H‑bonding. Requires protection (e.g., Boc/Fmoc on Nα, benzyl/tert‑butyl or silyl protection of the γ‑OH, and esterification of C‑terminus) before SPPS/LPPS.
  • Chemoselective derivatization: The secondary alcohol enables selective acylation, carbamate formation (e.g., with CDI), or Mitsunobu inversion to access epi‑isomers or O‑alkylated analogs.
  • Lactonization: Under dehydrative conditions, intramolecular ester formation can afford γ‑lactones—useful intermediates in diversity‑oriented synthesis.
  • Resolution/chirality transfer: The multiple stereocenters allow chiral relay strategies; diastereomeric salt formation or enzymatic resolution may be used when racemates are prepared.
• Practical tips
  • Protecting group strategy dictates solubility and coupling efficiency; select orthogonal protections compatible with your route (e.g., Fmoc‑strategy for SPPS with acid‑labile side‑chain protection for –OH).
  • Minimize base exposure during workups to avoid β‑elimination or epimerization at C2; perform couplings at controlled pH and low temperature when possible.
  • For analytical tracking, derivatize with Marfey’s reagent or PITC for enhanced UV detection.

Reaction Conditions

The following are literature‑style general conditions for transformations involving hydroxy‑substituted amino acids like 4‑hydroxy isoleucine; optimize for your substrate and verify with small‑scale trials.

• Peptide coupling (solution phase)
  • Reagents: HATU (1.0–1.2 equiv), DIPEA (2–3 equiv) in DMF/DMF–CH2Cl2; or EDC·HCl (1.2–1.5 equiv) with Oxyma (1.2 equiv) in DMF or water/DMF.
  • Temperature/time: 0–25 °C, 0.5–12 h depending on sterics.
  • Notes: Protect γ‑OH to prevent undesired O‑acylation. Minimize base to avoid epimerization at C2.
• O‑Acylation of γ‑OH
  • Reagents: Acyl chloride/anhydride (1.1–1.5 equiv), DMAP (0.05–0.2 equiv), pyridine or CH2Cl2 with added base.
  • Temperature/time: 0 °C to RT, 1–6 h.
  • Selectivity: Protect Nα (Boc/Fmoc) and C‑terminus (ester) first for clean O‑acylation.
• Mitsunobu inversion/alkylation (to invert C4 configuration)
  • Reagents: DEAD or DIAD (1.2 equiv), PPh3 (1.2 equiv), ROH or acid pronucleophile in THF/THF–DMF.
  • Temperature/time: 0–25 °C, 2–12 h.
  • Caution: Sensitive to moisture; ensure terminals are protected; handle azodicarboxylates with care.
• Lactonization (γ‑lactone formation)
  • Reagents: DCC or EDC with catalytic DMAP; or acid catalysis (p‑TsOH) in toluene with azeotropic water removal.
  • Temperature/time: RT to reflux, 2–24 h.
  • Control: Monitor to avoid over‑cyclization or dehydration side products.
• Analytical monitoring
  • RP‑HPLC with ion‑pairing or HILIC for polar intermediates; LC‑MS for mass tracking.

Yields vary widely with protection strategy and stereochemistry; consult primary literature for closely related substrates and scale‑up guidance.

Safety and Handling

• Authoritative source: Always consult the product SDS for definitive hazard classification, PPE, and first‑aid instructions.
• GHS/CLP status (from Product Data)
  • Signal word: Not specified for this item; refer to SDS.
  • H‑statements: Not specified for this item; refer to SDS.
  • GHS classification/pictograms: Not specified for this item; refer to SDS.
• General laboratory handling (amino acids; informational)
  • Low volatility solid; dust generation should be minimized. Avoid inhalation of dusts and contact with eyes/skin.
  • Use standard PPE: lab coat, safety glasses, and suitable gloves (e.g., nitrile). Handle in a clean, dry environment.
  • Hygroscopicity for many amino acids is moderate; keep containers tightly closed to avoid moisture uptake and caking.
• Incompatibilities and stability (general)
  • Incompatible with strong oxidizers and strong mineral acids or bases under forcing conditions (may cause degradation).
  • Amino acids can undergo Maillard‑type reactions with reducing sugars upon heating; avoid unnecessary heat in presence of carbonyl compounds.
  • Avoid prolonged exposure to elevated temperatures; decomposition/melting may occur with browning.
• First‑aid overview (general guidance; defer to SDS)
  • Inhalation: Move to fresh air; seek medical attention if symptoms persist.
  • Skin/eye contact: Rinse with water for several minutes; remove contaminated clothing; seek medical attention if irritation develops.
  • Ingestion: Rinse mouth; do not induce vomiting; seek medical advice if unwell.
• Fire safety
  • Organic solid; combustible at high temperature. Use water spray, CO2, foam, or dry chemical for incipient fires. Thermal decomposition may produce nitrogen oxides and carbon oxides.

Solvent Selection

4‑Hydroxy isoleucine is a polar, zwitterionic α‑amino acid; solvent behavior follows that class.

• Polarity/miscibility (literature/generic trends)
  • Highly soluble in water across a range of pH; solubility often increases markedly at pH <2 (cationic) or pH >10 (anionic).
  • Poorly soluble in nonpolar and many aprotic organic solvents (e.g., hexanes, toluene, CH2Cl2). Limited solubility in MeOH/EtOH; improved in water–alcohol mixtures.
  • Partitioning: Very low organic/water partitioning at neutral pH due to zwitterion formation.
• Practical choices by task
  • Stock solutions: Use water or aqueous buffers (e.g., 10–100 mM). Adjust pH to 1–2 (HCl) or 10–11 (NaOH) to increase solubility if needed; return to target pH after dilution.
  • Peptide coupling/derivatization: Dissolve as the appropriate salt in polar aprotics with additives (DMF/DMSO with small amounts of base/activator) or use water‑compatible coupling systems.
  • Chromatography: For RP‑HPLC, use ion‑pairing or high aqueous mobile phases; HILIC is often effective for retention.
• Comparison (general)
  • Water: Best solvating medium; biocompatible; may require pH control.
  • DMSO: Excellent for concentrated stocks when water solubility is limiting; viscous and can complicate bioassays at >1–2% v/v.
  • Methanol/Ethanol: Moderate aid in co‑solvent systems; limited alone at neutral pH.
• Tips
  • Filter aqueous solutions (0.22–0.45 µm) to remove particulates prior to analytical or biological use.
  • Avoid high‑pH storage; β‑elimination/dehydration of hydroxy amino acids can occur under strong basic conditions over time.

Storage and Reconstitution

• Storage conditions (from Product Data)
  • Store at 2–8 °C.
  • Shipped on wet ice.
• General stability guidance
  • Keep container tightly closed in a dry environment. Protect from excessive heat and prolonged exposure to high pH to minimize degradation (e.g., dehydration or lactonization pathways in hydroxy amino acids).
  • For long‑term studies, consider storing as desiccated solid at 2–8 °C; if material is hygroscopic, limit headspace humidity.
• Reconstitution (aqueous use)
  • Solvent: Water or appropriate buffer. Start with 10–100 mM stocks.
  • pH: Adjust to facilitate dissolution if necessary (acidic or mildly basic), then readjust to the desired working pH.
  • Filtration: For cell‑related work, sterile‑filter through 0.22 µm. Avoid repeated freeze–thaw of solutions; prepare single‑use aliquots.
  • Light sensitivity: Not typically light‑sensitive; however, store solutions in amber vials as a good laboratory practice when prolonged storage is expected.
• Solution stability (general)
  • Aqueous solutions are typically stable for days to a few weeks at 2–8 °C depending on pH. For maximum integrity, prepare fresh before critical experiments.
• Specifications not provided
  • Appearance, exact solubility, and concentration limits: Not specified for this item; refer to CoA/Spec Sheet.

Research Use Note: For research use only (per Product Data).

Structure and Identity

4‑Hydroxy isoleucine is a hydroxylated, branched‑chain amino acid structurally related to L‑isoleucine and commonly encountered as the fenugreek metabolite 4‑hydroxy‑L‑isoleucine.

• Item-specific identifiers (from Product Data)
  • SKU: H134438
  • CAS: 781658-23-9
  • PubChem CID: 2773624
  • InChIKey: 265937 (as provided)
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
• Literature identity (for reference only; not item specifications)
  • Common name: 4‑Hydroxyisoleucine (often encountered as the L‑isomer: 4‑hydroxy‑L‑isoleucine)
  • Molecular formula (free amino acid, literature): C6H13NO3
  • Molecular weight (literature): ~147.17 g/mol
  • Stereochemistry: Naturally occurring material is typically 2S,3R,4S (literature). Commercial materials may be enantiopure or mixtures; verify CoA.
• Structural features (descriptive)
  • Backbone: α‑amino acid with a carboxylic acid (–CO2H) at C1 and a primary amino group (–NH2) at C2.
  • Side chain: A branched alkyl chain analogous to isoleucine bearing a secondary alcohol at the γ‑position (C4). One methyl branch at C3.
  • Functional groups: α‑amino (basic), α‑carboxyl (acidic), secondary alcohol (neutral, H‑bond donor/acceptor).
  • Zwitterion formation: At neutral pH the amino group is typically protonated (–NH3+) and the carboxylate deprotonated (–COO−). This strongly influences solubility and chromatography.
• 2D structure in words
  • Starting from the carboxyl carbon (C1), the α‑carbon (C2) bears –NH2 and the side chain; the β‑carbon (C3) is substituted with a methyl; the γ‑carbon (C4) carries –OH and continues to a terminal methyl. Three stereogenic centers may be present depending on substitution pattern.

Synthetic Utility

4‑Hydroxy isoleucine offers a compact set of orthogonal functionalities: a nucleophilic α‑amine, a carboxylic acid, and a secondary alcohol on a β‑branched side chain. This constellation enables diverse, chemoselective transformations.

• Functional group handles
  • Nα: Protect as Boc or Fmoc; convert to ureas/carbamates; engage in reductive amination with prior carboxyl protection.
  • C‑terminus: Esterify (Me, Bn, tBu) to facilitate O‑acylation at the side‑chain OH without backbone scrambling.
  • γ‑OH: Form carbonates, esters, or undergo Mitsunobu reaction for inversion/alkylation; oxidize to ketone (carefully) to access 4‑oxo isoleucine analogs.
• Named/typical reactions
  • Peptide coupling: HATU/DIPEA or EDC/Oxyma systems; SPPS with Fmoc‑strategy and acid‑labile side‑chain protection on OH.
  • Intramolecular cyclization: Dehydrative lactonization to γ‑lactones; subsequent ring‑opening provides access to regio‑ and stereochemically diverse derivatives.
  • Chemoenzymatic steps: Lipase‑mediated acylations at the secondary alcohol can provide high stereocontrol under mild, green conditions.
• Retrosynthetic value
  • Serves as a chiral pool starting point for γ‑functionalized BCAA motifs in natural products and peptidomimetics.
  • The β‑branch and γ‑OH enable chiral relay to construct vicinal stereocenters in adjacent frameworks.
• Practical guidance
  • Sequence protection to avoid over‑acylation and minimize epimerization at C2; conduct couplings at ≤0–25 °C when feasible.
  • Monitor reactions by LC‑MS; derivatize for UV detection if needed (e.g., Fmoc‑Cl, Marfey’s).
  • For O‑acylations, use mild bases (pyridine, DMAP) and pre‑protected N/C termini to ensure selectivity.

Target Specificity

This product is a small‑molecule amino acid standard/building block and is not an antibody, enzyme, or receptor ligand with defined biological target specificity. No target, epitope, or isotype information applies.

• Item-specific data: None provided in Product Data for target specificity.
• Guidance: If using as a probe or standard in bioassays, define your target and validation strategy empirically (transporters, enzymes, or signaling readouts) and cite primary literature for assay‑specific interactions.