≥97% pour les flux de travail chromatographiques et analytiques sensibles nécessitant une interférence de ligne de base minimale.
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Stockage & expédition
Room temperature,Argon charged,Desiccated Expédition Normal. Consultez le COA spécifique au lot pour les spécifications exactes.
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Documents qualité
SDS, COA, fiche technique et fiche de spécifications disponibles au téléchargement. COA spécifique au lot accessible via la recherche par numéro de lot.
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Preuve documentaire
Cité dans 32 publications à comité de lecture couvrant la chromatographie, la synthèse organique et les réactions de couplage croisé.
Vue d’ensemble
L-Pyroglutamic acid is a building block for pharmaceuticals and asymmetric synthesis. A building block for pharmaceuticals and asymmetric synthesis
Cyclized derivative of L-Glutamic acid. Metabolite in the glutathione cycle.
Conditions de stockage de stockage
Room temperature,Argon charged,Desiccated
Expédié en
Normal
Note
Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20°C. Generally, these will be useable for up to one month. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour. Need more advice on solubility, usage and handling? Please visit our frequently asked questions (FAQ) page for more details.
This compound belongs to the class of organic compounds known as alpha amino acids and derivatives. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon), or a derivative thereof.
External Descriptors
Other amino acids
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.
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Application Protocols
No item-specific, validated application protocols are provided for this SKU. The following brief, literature-style guidance illustrates common laboratory use; adapt to your system.
Stock solution preparation (analytical): Dissolve H-Pyr-OH at 10–100 mg/mL in water, PBS (pH ≥7), or DMSO. Sonicate if needed. Filter (0.22 µm) for LC/UPLC.
SPPS coupling to install N-terminal pGlu:
Pre-swell resin in DMF. Deprotect the terminal amine (as applicable).
Prepare 0.1–0.2 M H-Pyr-OH in DMF; add HATU (2 equiv) and DIPEA (4 equiv). Brief pre-activation (<3 min).
Add to resin (3–5 equiv vs resin loading). Agitate 45–90 min at rt.
Wash DMF and test (Kaiser). Repeat coupling if necessary.
Cap/unreacted amines as per standard workflow; proceed to cleavage.
Active ester formation (NHS): Dissolve H-Pyr-OH (1.0 equiv) and NHS (1.1 equiv) in dry DMF at 0 °C; add EDC·HCl (1.1 equiv) and catalytic DMAP; stir 1–2 h at 0–5 °C, then to rt for 1 h. Use immediately or isolate under low moisture.
All parameters above are general literature guidance only. Verify on small scale and consult method-specific references. For GMP or regulated work, establish formal procedures and release criteria.
Biological Roles
Literature/general context for the pyroglutamyl residue and pyroglutamic acid (5-oxoproline):
Protein/peptide chemistry: Pyroglutamate (pGlu, 5-oxoproline residue) commonly forms at N-termini of peptides and proteins via intramolecular cyclization of N-terminal glutamine or glutamate. This modification can influence peptide stability against aminopeptidases and modulate receptor interactions and biophysical properties.
Metabolic role: 5-Oxoproline is an intermediate in the γ-glutamyl cycle (glutathione metabolism). Enzyme 5-oxoprolinase converts 5-oxoproline to L-glutamate, contributing to glutathione turnover and amino acid homeostasis.
Acid–base and ionization: As a carboxylic acid-bearing lactam, pyroglutamic acid is predominantly deprotonated at physiological pH (forming the carboxylate), while the lactam nitrogen remains largely non-ionized. This impacts solubility and transport across membranes.
Occurrence: pGlu-capped peptides are found across taxa (eukaryotes, prokaryotes). The modification can arise enzymatically (glutaminyl cyclases) or non-enzymatically under conducive conditions.
Structural implications: The 5-membered lactam imparts conformational constraint near the N-terminus, often reducing local flexibility and influencing secondary structure propensity.
Analytical markers: In proteomics, N-terminal pGlu can affect MS/MS fragmentation; specific sample prep (e.g., enzymatic de-blocking with pyroglutamate aminopeptidase) may be employed to improve sequence coverage.
Note: The above describes general biochemical roles of the pGlu motif. This product is provided strictly for laboratory research use and is not intended for diagnostic or therapeutic applications.
Buffer Applications
This compound is not a standard laboratory buffering agent. As a carboxylic acid-containing lactam, it can contribute limited buffering capacity near its carboxyl pKa (~3.5, literature), but it is not typically used to prepare defined buffer systems.
Practical note: If dissolution in aqueous media is required, adjust pH to 7.0–8.0 with minimal base to aid solubility while avoiding conditions that promote ring opening. For controlled pH studies, employ established buffers (e.g., acetate for pH 4–5.5, phosphate for pH 6–8) and dissolve H-Pyr-OH into those systems.
For experiments requiring precise pH control or buffering capacity, select a dedicated buffer component rather than relying on H-Pyr-OH.
Green Alternatives
While H-Pyr-OH itself is a solid building block, its use commonly involves solvents and coupling reagents with environmental, health, and safety (EHS) burdens. The following greener strategies (literature/general) may improve process sustainability without compromising performance:
Solvent choices:
Replace DMF/NMP with NBP (N-butyl-2-pyrrolidone), PolarClean (dimethyl 5-methyl-2,4-pyridinedicarboxylate), Cyrene/blends, or propylene carbonate where solubility permits.
Employ 2-MeTHF or EtOAc for solution-phase steps (workups, crystallizations) instead of chlorinated solvents.
Coupling reagents/additives:
Favor OxymaPure with DIC as a lower-hazard alternative to HOBt/HOAt systems; minimize azabenzotriazole handling.
Explore green carbodiimides (e.g., DIC) and water-tolerant coupling in mixed aqueous media when feasible.
Process intensification:
Use high-loading resins and optimized stoichiometry to reduce solvent volumes in SPPS.
Microwave or flow-enabled coupling can shorten reaction times and energy use while maintaining low racemization.
Waste minimization:
Implement solvent recycling/distillation for DMF/MeCN; switch to buffered aqueous workups to reduce halogenated waste.
Illustrative comparison (literature/general):
DMF vs NBP: DMF offers superior mass transfer and fast kinetics, but is reprotoxic and tightly regulated; NBP shows comparable solvating power for many amino acids (including pGlu) with a better EHS profile, though viscosity may slow resin swelling/diffusion.
Always validate green substitutions at lab scale to confirm coupling efficiency, solubility, and product quality.
Pharmaceutical Uses
No item-specific pharmacopeial status or excipient grade is provided for this SKU; refer to the CoA/Spec Sheet.
General formulation/manufacturing context (literature/general):
Role in APIs: Pyroglutamic acid (pGlu) is a common N-terminal motif in peptide active substances. H-Pyr-OH can serve as a raw material for manufacturing such peptides via SPPS or solution-phase coupling. Specifications typically emphasize identity (including stereochemistry), residual solvents, heavy metals/elemental impurities (ICH Q3D), water content (KF), and assay.
Salt and polymorph considerations: This compound is generally used as the free acid. Given its hydrophilicity, formation of salts is less common than for basic amino acids; polymorphism is not widely reported as a critical concern.
Process compatibility: Readily handled in aqueous or polar aprotic systems compatible with typical GMP processes. Analytical methods include HPLC with UV at low wavelengths (end-absorbance) or ELSD; LC–MS for identity confirmation.
Stability: Solid-state stability is generally good at ambient storage when dry and protected from light and moisture. In solution, hydrolysis/ring opening can occur under strong basic conditions; neutral to slightly acidic solutions are preferred for holding.
Note: This product is supplied strictly for research use only and is not intended for use in humans or for clinical applications.
Physical Properties
Item-specific specification values are not provided for this SKU; consult the CoA for batch-specific data. The following are literature/general properties of L-pyroglutamic acid (L-5-oxoproline):
Appearance: Not specified for this item; refer to CoA/Spec Sheet. (Literature: typically white to off-white crystalline solid.)
LogP (estimated, literature): negative (hydrophilic character); reported cLogP near −0.6 to −1 depending on model
Optical rotation: depends on concentration/solvent; Not specified for this item; refer to CoA/Spec Sheet.
UV/Vis: no strong chromophore; end-absorbance only (literature). Cutoffs/ε: Not specified for this item; refer to CoA/Spec Sheet.
Important: Do not treat these literature values as product specifications.
Quality and Grades
Item-specific grade/purity: Not specified for this item; refer to CoA/Spec Sheet.
Context and guidance for this material (literature/general):
Typical offerings for H-Pyr-OH (pyroglutamic acid) span:
Peptide synthesis grade: low inorganic/organic impurities, controlled water content, and low trace metals to minimize coupling side reactions and maximize SPPS yields. Vendors may also monitor optical purity (ee) for the L-form.
Reagent grade: suitable for general organic synthesis; broader impurity limits versus peptide grade.
BioReagent grade: assessed for certain bioapplications (e.g., endotoxin/bioburden), when applicable.
Stabilizers: None are typically required for stable amino-acid derivatives like pyroglutamic acid; this item lists no stabilizer.
UV/LC suitability: For analytical or HPLC uses (e.g., monitoring coupling), low UV background and particulates are desirable; HPLC or peptide grade minimizes baseline noise.
Identity/optical purity: For chiral building blocks, vendors commonly report [α]D or chiral HPLC. If chirality matters in your application (L- vs D-), request or verify supporting documentation.
Recommendation: For solid-phase peptide synthesis (SPPS) or enantioselective work, select peptide grade with certified optical purity and tight impurity controls. For general synthesis or as a biochemical standard, reagent grade may suffice. Always verify specifications on the CoA for the purchased lot.
Reaction and Applications
H-Pyr-OH (pyroglutamic acid) is a versatile building block in peptide and heterocycle chemistry.
Key applications (literature/general):
Peptide synthesis (SPPS and solution phase): introduces the N-terminal pyroglutamyl (pGlu, Glp, Pyr) residue. pGlu often modulates peptide stability and receptor interactions. Coupling is typically performed under standard peptide activation (HATU/HBTU/TBTU, DIC/EDC + Oxyma/HOAt/HOBt) with DIPEA or collidine base in DMF or NMP.
Masked glutamate strategy: ring opening of pyroglutamic acid or its derivatives provides access to L-glutamic acid or γ-substituted glutamates after selective transformations on the ring carbonyl.
Stereocenter relay: the α-stereocenter can guide asymmetric transformations on ring substituents, with subsequent ring opening to deliver enantioenriched acyclic targets.
Cyclization/re-cyclization chemistry: forms diketopiperazines and other lactam-containing scaffolds via condensation with amino components.
Protecting group chemistry: as a cyclic analog of Glu, the lactam can serve as a transient “protection” of the backbone nitrogen while leaving the carboxyl free for further elaboration.
Bioconjugation: activation to NHS esters or pentafluorophenyl esters enables coupling to amines on biomolecules to install pGlu tags.
Practical tips (literature):
Ensure dryness of activation solutions to suppress premature hydrolysis. Use 2–4 equiv of coupling reagent and base; 0.1–0.2 M substrate concentration is common.
Racemization risk is typically low for pGlu couplings, but maintain temperatures ≤25 °C and avoid prolonged pre-activation.
Excess base or strong alkaline conditions can promote ring opening; maintain pH control during aqueous workups.
Reaction Conditions
General, literature-based guidance for common uses of H-Pyr-OH; adjust to your system and consult primary sources.
Peptide coupling (installing N-terminal pGlu):
Solvent: DMF or NMP (or greener NBP/PC where validated).
Activation: HATU or HBTU (1.5–3.0 equiv), with DIPEA (2–6 equiv). Alternative: DIC (2–3 equiv) + OxymaPure (1–2 equiv).
Concentration: 0.05–0.2 M in amino component.
Temperature/time: 20–25 °C; 30–120 min typical. Monitor by Kaiser/chloranil tests (SPPS) or TLC/HPLC (solution).
Notes: Minimize pre-activation time (<5 min) to limit side reactions. Racemization is typically low but confirmed by chiral HPLC when critical.
Formation of active esters (NHS/PFP):
EDC or DIC (1.1–1.5 equiv), NHS or PFP (1.1–1.5 equiv), in DMF or DCM/DMF; catalytic DMAP as appropriate; 0–25 °C, 1–4 h.
Workup: aqueous bicarbonate then brine; avoid strong base to prevent ring opening.
Ring opening to glutamate derivatives:
Base-catalyzed hydrolysis: aq. NaOH (0.5–2 M), 0–25 °C, 0.5–4 h to form L-glutamate salts; neutralize carefully.
Aminolysis/alcoholysis: amine or alcohol nucleophile with catalytic/base activation (e.g., NaOMe/MeOH), 0–25 °C.
Reductions of the lactam (on protected derivatives):
BH3·THF or LiAlH4 under anhydrous conditions; 0–25 °C; quench cautiously. Typically performed on ester-protected variants to control chemoselectivity.
Typical isolated yields: 70–95% for peptide couplings under optimized conditions; lower for multi-step derivatizations depending on protection strategy.
Safety and Handling
Item-specific GHS data were not provided. Always consult the product SDS for authoritative safety information.
GHS/Classification (item-specific):
Signal word: Not specified for this item; refer to SDS.
Hazard statements: Not specified for this item; refer to SDS.
Pictograms: Not specified for this item; refer to SDS.
General safety considerations for pyroglutamic acid (literature/general):
Expected hazards: low acute toxicity profile for amino-acid derivatives; may cause eye, skin, or respiratory irritation. Avoid dust generation and inhalation.
Personal protective equipment: lab coat, safety glasses, and appropriate chemical-resistant gloves (e.g., nitrile). Use a dust mask or work in a fume hood if airborne dust may form.
Handling: avoid moisture uptake; keep containers tightly closed. Use clean, dry tools. Minimize exposure and practice good hygiene.
Incompatibilities: strong bases (promote hydrolysis/ring opening to glutamate), strong acids (possible dehydration or decomposition at elevated temperatures), strong oxidizers (general).
Thermal stability: decomposes on strong heating; avoid temperatures above mp.
First aid (overview; defer to SDS):
Inhalation: move to fresh air; seek medical advice if symptoms persist.
Skin/eyes: rinse with water for several minutes; remove contaminated clothing; seek medical advice if irritation persists.
Ingestion: rinse mouth; do not induce vomiting; seek medical attention if unwell.
Spill/collection: avoid dust; sweep up with minimal agitation; place in suitable container for disposal according to local regulations.
Solvent Selection
This product is a solid building block, not a solvent. However, solvent choice strongly impacts its handling, dissolution, and use in synthesis and analysis.
Polarity/acid–base character (general): amphoteric but effectively acidic due to the carboxyl group; the lactam N is non-basic. Exhibits good hydrogen-bonding capacity; favors polar solvents.
Dissolution guidance (literature):
Aqueous media: readily dissolves in water above its pKa (as the carboxylate). Neutral water offers moderate solubility; adjust pH to ~7.5–8.5 for rapid dissolution, avoiding strong base if ring opening to glutamate is a concern.
Polar aprotic: dissolves well in DMSO or DMF; useful for stock solutions in biochemical assays or for SPPS solutions prior to activation.
Alcohols: methanol/ethanol provide limited-to-moderate solubility; heating or sonication may assist.
SPPS: typically weighed directly on resin or dissolved in DMF/NMP prior to activation (HATU/HBTU/DIC+Oxyma) and coupling.
Analytical: aqueous buffers or water/acetonitrile with formic acid for LC-MS.
Comparison notes (literature):
DMF/NMP vs greener alternatives (e.g., NBP, PC, 2-MeTHF): DMF/NMP deliver excellent solubility and fast kinetics but pose EHS concerns; N-butyl-2-pyrrolidone (NBP) or dimethyl carbonate mixtures may be considered where feasible.
Always confirm solvent compatibility with your downstream chemistry and equipment.
General best practices (literature/general) for this class of material:
Storage:
Keep tightly closed in a dry, inert atmosphere (desiccator recommended) to avoid moisture uptake and potential hydrolysis.
Protect from excessive heat and direct light. Avoid prolonged exposure above ambient temperatures.
Segregate from strong bases and oxidizers.
Shelf life: Solid-state stability is generally good when stored dry at room temperature; confirm retest/expiry on the CoA.
Reconstitution/dissolution:
Aqueous: Dissolve directly in water or buffer. For rapid dissolution, adjust to pH 7.0–8.0 with minimal base. Avoid strong alkaline conditions that promote ring opening to glutamate.
Organic: Dissolve in DMSO or DMF to prepare concentrated stocks (e.g., 0.1–1.0 M). Filter sterilize (0.22 µm) for cell-free biochemical assays if needed.
Storage of solutions: Prefer freshly prepared solutions. If storage is required, keep at 2–8 °C for short periods (hours–days) and at ≤−20 °C for longer-term, minimizing freeze–thaw cycles. Inspect for precipitation or pH drift prior to use.
Note: Specific appearance, assay, water content, and other release criteria are Not specified for this item; refer to CoA/Spec Sheet. Always follow the SDS for handling and disposal.
Structure and Identity
A cyclic amino acid derivative widely used in peptide chemistry as the pyroglutamyl (pGlu, Pyr, Glp) building block.
Item-specific identifiers (Product Data):
SKU: P106003
Product Name: H-Pyr-OH
CAS: 98-79-3
Storage: Room temperature (as provided)
Shipped In: Normal (as provided)
Category: 生命科学 (Life Science); research use only
Core identity (literature/general):
Preferred chemical name (literature): L-Pyroglutamic acid (L-5-oxoproline; L-pyrrolidone-2-carboxylic acid); commonly abbreviated Pyr, Glp, or pGlu in peptides
Molecular formula (literature): C5H7NO3
Molecular weight (literature): ~129.11 g/mol
2D structure description: A 5-membered lactam ring (pyrrolidone) bearing a carboxylic acid at C-2. The ring contains one carbonyl (lactam) and one secondary amide N–H; the side-chain is a –CH2–CH–CO2H fragment completing the ring. One stereocenter at the α-carbon (L-configuration in the naturally occurring form).
Functional groups: cyclic amide (lactam), carboxylic acid; amphoteric but predominately acidic due to CO2H.
InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
Notes
“H-Pyr-OH” in peptide nomenclature denotes free N (as lactam N–H) and free C-terminus (–CO2H) of the pyroglutamyl residue.
Synthetic Utility
Pyroglutamic acid (H-Pyr-OH) is a compact, bifunctional building block with a carboxylic acid and a 5-membered lactam, enabling diverse transformations (literature/general):
Peptide coupling: Activated as mixed anhydrides or via uronium/phosphonium reagents (HATU/HBTU/TBTU, PyBOP), it couples efficiently to amines to install an N-terminal pGlu residue. Low racemization is typical under mild base (e.g., DIPEA) at room temperature.
Ring opening to glutamate derivatives: Nucleophiles (e.g., hydroxide, amines, alcohols) open the lactam to generate γ-substituted glutamates. This masks-functionality strategy allows selective manipulations at the ring carbonyl prior to unveiling the linear amino acid.
Chiral pool precursor: The single stereocenter provides entry to enantioenriched pyrrolidone scaffolds, β- and γ-functionalized acids, and diketopiperazines. Stereochemical integrity can be maintained with judicious conditions.
Derivatization handles:
Carboxyl: formation of esters (e.g., methyl/benzyl) for protecting groups; NHS/PFP active esters for bioconjugation.
Lactam carbonyl: reduction (e.g., borane, LiAlH4 in protected forms) to amino alcohols; thionation (Lawesson’s) to thioamide analogs (on protected substrates).
Orthogonal protection strategies: Conversion to protected pyroglutamate derivatives (e.g., OMe, OBn esters) enables selective downstream chemistry and compatibility with SPPS.
Heterocycle synthesis: Serves as a synthon to access substituted pyrrolidinones and proline derivatives via functionalization and rearrangement.
Overall, H-Pyr-OH functions as a stable, crystalline, chiral synthon and a reliable pGlu donor for peptide and conjugation workflows.
Target Specificity
Not applicable. This product is a small-molecule building block (pyroglutamic acid), not an antibody, enzyme, or affinity reagent. No antigen/epitope or species reactivity data apply.
Foire aux questions
What is the purity of this product?
This product is supplied at ≥97% purity (chemical assay). Lot-specific values are stated on the Certificate of Analysis.
How should this product be stored?
Store at room temperature.
How is this product shipped?
This product ships under standard ambient conditions. No temperature-controlled packaging is required.
What are the CAS number, molecular formula and molecular weight?
The CAS Number is 98-79-3, the molecular formula is C5H7NO3, and the molecular weight is 129.11 g/mol. InChIKey ODHCTXKNWHHXJC-VKHMYHEASA-N.
What documentation is provided?
Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.
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