HS-PEG9-CH2CH2COOH , CAS No.H1444777

CAS: H1444777 Cat. No.: H1444777 Formule: C₂₁H₄₂O₁₁S Poids moléculaire: 502.62

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

Vue d’ensemble

HS-PEG9-CH2CH2COOH is a PEG-based PROTAC linker that can be used in the synthesis of PROTACs.

Specifications

Conditions de stockage de stockage

Store at -20°C

Expédié en

Ice chest + Ice pads

Ce produit nécessite l'expédition en chaîne froide. Les services terrestres et autres services économiques ne sont pas disponibles.

Noms et identifiants

Poids moléculaire

502.62

Application Protocols

Not applicable. No tested biological assay applications (e.g., WB, IHC, IF, FC) or recommended dilutions are relevant for a small-molecule PEG linker. For practical use, refer to the Reaction & Applications and Reaction Conditions sections for general conjugation guidance.

Biological Roles

This product is a synthetic heterobifunctional PEG linker and does not have an intrinsic biological role.

• General context (literature/practice):

  • PEG spacers are widely used in research to modulate hydrophilicity, reduce nonspecific interactions, and provide flexible separation between functional groups in biomolecule conjugates, surfaces, and nanomaterials.
  • The thiol end enables chemoselective conjugation to cysteine residues or maleimide-functional partners, while the carboxylic acid can be converted to amide linkages with amines via carbodiimide chemistry.
  • PEGylation can reduce protein adsorption and improve aqueous dispersibility of materials in laboratory studies; these are physicochemical effects, not therapeutic claims.

• Note: No endogenous metabolic or signaling functions are attributed to this synthetic linker. Any biological testing should be performed strictly for research purposes as indicated by the product’s Research Use Only designation.

Buffer Applications

This reagent is not a buffering agent and is not used to set or maintain pH. However, buffer selection is important for its bioconjugation reactions (general guidance):

• Carbodiimide coupling of the –COOH terminus:
  • Activation phase: mildly acidic buffers (e.g., MES, pH 4.5–6.0) support EDC activation and suppress O-acylisourea rearrangements.
  • Coupling phase: near-neutral buffers (phosphate, pH 6.8–7.4) or slightly basic (HEPES, pH 7.5–8.0) facilitate amide formation with amines.
• Thiol–maleimide coupling:
  • Use degassed phosphate or HEPES buffers at pH 6.5–7.0 to minimize thiol oxidation and side reactions (maleimide hydrolysis increases >pH 7.5).
  • Include a compatible reducing agent (e.g., TCEP at 0.1–1 mM) when maintaining the thiol in its reduced state is critical; avoid thiol-containing reducers (DTT, βME) that compete in conjugation.

All buffer compositions and concentrations should be optimized for the specific substrates and are provided here as literature-based guidance, not item-specific specifications.

Green Alternatives

While HS-PEG9-CH2CH2COOH is a reagent rather than a solvent, greener choices can be made in the processing solvents and activation strategies used with it.

• Greener solvent choices (literature/general):
  • Prefer water or aqueous buffers for EDC-mediated coupling where feasible; use ethanol or isopropanol as co-solvents in place of higher-toxicity polar aprotics when substrate solubility allows.
  • Replace DCM with ethyl acetate or 2-methyltetrahydrofuran (2-MeTHF) for extractions or organic-phase activations where compatible.
  • Use acetonitrile or ethanol as alternatives to DMF for some NHS-ester preparations, recognizing trade-offs in solubility and reaction rate.

Comparison (general guidance):

• DMF/DMSO: excellent solubility; reproductive toxicity (DMF) and difficult removal (DMSO). Manage with minimal volumes and closed systems.

• Water/Buffer + EtOH co-solvent: greener profile, easier workup; may limit solubility for hydrophobic counterparts and can accelerate NHS hydrolysis.

• 2-MeTHF/EtOAc: lower toxicity/renewable origins; may not dissolve PEG linkers as effectively; often better for workup rather than coupling.

• Process considerations:

  • Run at ambient temperature where possible to reduce energy use; employ catalytic activating agents judiciously.
  • Use in-situ activation (EDC) to avoid isolating active esters and reduce solvent consumption.
  • Implement solvent recovery and peroxides monitoring for ether-rich waste streams.

Pharmaceutical Uses

No pharmacopeial status, excipient designation, or clinical application information is provided for this item.

• Not specified for this item; refer to CoA/Spec Sheet for any available regulatory or quality notes.
• General research-context information (non-clinical):
  • Heterobifunctional PEG linkers like HS-PEGn-COOH are used in laboratory-scale process development to prototype conjugation workflows (e.g., model antibody/peptide–payload coupling, nanoparticle surface modification) due to their hydrophilicity and chemoselectivity.
  • Any use in drug product manufacturing or clinical studies would require dedicated qualification, regulatory review, and grade verification not provided here.

Research Use Only: As stated in the Product Data, this item is for research use only and not for human or veterinary use.

Physical Properties

Item-specific numeric properties are not provided in the Product Data.

• Not specified for this item; refer to CoA/Spec Sheet:
  • Molecular weight; molecular formula; exact mass
  • Melting point; boiling point; density; refractive index
  • Water content; residual solvents; UV cutoff; metal content
• General/literature characteristics for PEG linkers of similar length (for context only):
  • Physical form: short PEG oligomers are commonly low-melting waxy solids or viscous oils; appearance varies with purity and end-groups (literature).
  • Solubility (literature): typically highly soluble in polar organic solvents (DMF, DMSO, MeOH, EtOH, acetonitrile) and water; poor solubility in nonpolar hydrocarbons.
  • Partitioning: PEG chains confer hydrophilicity and reduce logP versus purely aliphatic linkers (literature trend).
  • Hygroscopicity: PEG oligomers can be hygroscopic; they may absorb moisture that impacts coupling efficiency (literature).
• Practical implications (general guidance):
  • Prepare solutions using dry, oxygen-free solvents to protect the thiol from oxidation.
  • Degas aqueous buffers and consider adding reducing agents (e.g., TCEP) to maintain the –SH state during handling.

Quality and Grades

• Item-specific quality/grade and purity: Not specified for this item; refer to CoA/Spec Sheet.

• Context for professional users (general guidance):

  • Bioconjugation/Linker grade: Typically implies high organic purity (>95% by HPLC), low residual solvents, and low metal content to minimize side reactions with sensitive biomolecules. Low bioburden and low endotoxin may be specified for some applications (not stated here).
  • PEG oligomer homogeneity: HS-PEGn reagents can be offered as discrete-length (monodisperse) or as narrow dispersity mixtures. Verify by LC–MS/GPC as needed; the exact dispersity for this item is not specified.
  • End-group integrity: For heterobifunctional linkers, verify free thiol content (Ellman’s assay) and acid value or active ester content if pre-activated. Absence of disulfide dimer and hydrolyzed byproducts is important for reproducibility.
  • UV/fluorescence background: Not typically UV-transparent specifications are provided; check CoA if low-UV background is required for analytical workflows.

• Recommendations:

  • Request and review the current CoA/Spec Sheet for batch-specific purity, identity (NMR, MS), water content, and residual solvent data before use in critical coupling or surface chemistry work.

Reaction and Applications

HS-PEG9-CH2CH2COOH is a versatile heterobifunctional spacer for covalent assembly in materials science, chemical biology (non-clinical), and surface engineering.

• Representative applications (literature/practice):
  • Thiol–maleimide coupling: the free –SH rapidly adds to maleimides to form stable thioethers. Useful for site-selective conjugation to cysteine residues on peptides/proteins (research use) or to maleimide-functional polymers/nanoparticles.
  • Thiol–haloacetyl alkylation: reaction with iodo/haloacetyl substrates yields thioethers; typically slower than maleimide addition.
  • Disulfide chemistry: controlled formation of reversible disulfide bridges with another thiol; avoid adventitious dimerization by working under inert/reducing conditions.
  • Carbodiimide-mediated amide formation: the terminal –COOH can be activated with EDC/NHS (aqueous) or DIC/HOBt (organic) to couple with primary amines on ligands, surfaces, or polymers.
  • Gold/silver surface attachment: Au–S bond formation enables self-assembled monolayers and PEGylated antifouling coatings with terminal –COOH for further derivatization.
  • Linker engineering: the PEG9 spacer imparts hydrophilicity, flexibility, and reduced nonspecific binding compared to purely aliphatic linkers, improving solubility and biocompatibility in research constructs.
• Practical notes:
  • Maintain the thiol in reduced form (e.g., handle under N2/Ar; add TCEP freshly in aqueous buffers) to prevent disulfide dimer formation.
  • For amide couplings, control pH (carbodiimide reactions are optimal near pH 4.5–6.0 for activation; coupling with amines proceeds near neutral to slightly basic conditions). Minimize hydrolysis of activated esters by working efficiently at low temperature.

Reaction Conditions

Typical literature conditions are provided for planning purposes; optimize for your specific system. No item-specific specs are provided.

• Thiol–maleimide coupling:

  • Solvent: aqueous PBS or HEPES, optionally with 5–30% DMF/DMSO as co-solvent.
  • pH: 6.5–7.2 to minimize side reactions and maleimide hydrolysis.
  • Temperature: 4–25°C.
  • Time: 0.5–4 h, often complete within 1 h for properly deoxygenated solutions.
  • Notes: Degas buffers; include 0.1–1 mM TCEP if compatible; avoid excess bases.

• EDC/NHS-mediated amide formation (–COOH to amine):

  • Solvent: MES buffer (50–100 mM) or mixed DMF/H2O.
  • pH: activation at 4.5–6.0; coupling near pH 7.0–7.5.
  • Additives: NHS or sulfo-NHS (1–2 eq to acid) to form more stable active esters.
  • Temperature: 0–25°C.
  • Time: activation 10–30 min; coupling 1–4 h.
  • Notes: Work efficiently to limit NHS-ester hydrolysis; maintain stoichiometry to control degree of labeling.

• Thiol–haloacetyl alkylation:

  • Solvent: DMF, ACN, or aqueous bicarbonate.
  • Base: triethylamine or bicarbonate (mild).
  • Temperature: 0–25°C; longer times or gentle heating for less reactive substrates.

These conditions are general literature guidelines and not guaranteed specifications for this specific item.

Safety and Handling

Safety classifications are not provided in the Product Data.

• Not specified for this item; refer to SDS:
  • GHS signal word, hazard statements (H-codes), pictograms, and classification
• General safety considerations for thiol- and PEG-containing reagents (literature/practice):
  • Thiol functionality can oxidize to disulfides; handle under inert atmosphere where possible. Consider including a suitable reducing agent (e.g., TCEP) in aqueous work to maintain free –SH.
  • PEGs/ethers may form peroxides upon prolonged air/oxygen exposure; store tightly closed and minimize repeated air exchange; test for peroxides in aged solutions when appropriate.
  • Avoid strong oxidizers and strong bases/acids that may degrade the thiol or promote side reactions during activation.
• PPE and engineering controls:
  • Wear lab coat, safety glasses, and appropriate chemically resistant gloves; handle powders/solutions in a fume hood to avoid inhalation of aerosols or vapors.
• First-aid overview (consult SDS for definitive guidance):
  • Inhalation: move to fresh air; seek medical attention if symptoms persist.
  • Skin/eye contact: rinse with water for at least 15 minutes; remove contaminated clothing; seek medical advice for irritation.
  • Ingestion: rinse mouth; do not induce vomiting; seek medical attention.
• Fire and reactivity:
  • Combustible organic; use CO2, dry chemical, or foam to extinguish. Incompatible with strong oxidizing agents.
• Storage conditions (from Product Data):
  • Store at -20°C. Keep container tightly closed, desiccated, and protected from light and air.

Solvent Selection

This product is a functionalized PEG linker, not primarily a solvent; however, solvent choice is critical for successful coupling and handling.

• Polarity/miscibility (literature/general):
  • PEG linkers with ~9 EO units are generally highly soluble in water and polar organics (DMF, DMSO, MeOH, EtOH, ACN); solubility in nonpolar solvents (hexanes, toluene) is limited.
• Choosing solvents by application:
  • Carbodiimide coupling of the –COOH end to amines: anhydrous DMF or DMSO often used to dissolve the linker; aqueous activation/buffering at pH 4.5–6.0 (EDC) or mixed aqueous–organic media can balance reactivity and solubility.
  • NHS-ester strategies: activate the acid in dry DMF/DMF–DCM, then couple in buffered aqueous media (pH ~7–8) or in DMF with triethylamine, depending on substrate.
  • Thiol–maleimide conjugation: aqueous buffers (pH 6.5–7.0) or mixed DMF/water to minimize thiol oxidation; degas buffers and include TCEP if compatible.
  • Surface immobilization on gold: ethanol, isopropanol, or aqueous ethanol are commonly used to form self-assembled monolayers (SAMs) from thiols.
• Practical tips:
  • Use dry, oxygen-free solvents for stock solutions; aliquot and store frozen to limit oxidation/hydrolysis.
  • For poorly soluble targets, co-solvent systems (DMF/H2O or DMSO/H2O) can improve homogeneity while maintaining coupling efficiency.

Storage and Reconstitution

• Storage (from Product Data): Store at -20°C. Shipments are made on ice (ice chest + ice pads) to preserve quality during transit.

• Handling and preservation (general guidance):

  • Protect from moisture, air, and light. The free thiol is air-sensitive and can oxidize to a disulfide; maintain under inert gas when possible.
  • After opening, promptly aliquot into dry, oxygen-free vials; backfill with N2/Ar; keep tightly capped with desiccant present.
  • Avoid repeated freeze–thaw cycles; thaw only what is immediately required.

• Reconstitution (general literature guidance; not item-specific specification):

  • Prepare concentrated stocks in anhydrous, oxygen-free solvents such as DMF or DMSO. For aqueous use, dissolve in degassed buffer immediately before reaction.
  • Typical working concentrations: 1–100 mM depending on coupling strategy and substrate excess; optimize for your system.
  • For thiol-sensitive workflows, consider adding non-thiol reducing agents (e.g., TCEP at low millimolar levels) in aqueous buffers to maintain –SH.

• Stability notes (general):

  • Avoid storing pre-activated derivatives (e.g., NHS esters) for extended periods; generate in situ when feasible.
  • Inspect by LC–MS/HPLC for signs of dimerization (disulfide) or hydrolysis if material has been stored for prolonged periods.

• Documentation: For batch-specific stability, purity, and identity, consult the CoA/Spec Sheet.

Structure and Identity

HS-PEG9-CH2CH2COOH is a heterobifunctional polyethylene glycol (PEG) linker featuring a free thiol on one terminus and a terminal carboxylic acid separated by a short ethylene spacer on the other.

• Item-specific identifiers (from Product Data):
  • SKU: H1444777
  • CAS: H1444777 (catalogue placeholder)
  • Storage: Store at -20°C
  • Shipping: Ice chest + Ice pads
• Not specified for this item; refer to CoA/Spec Sheet:
  • Molecular formula; Molecular weight; SMILES; InChIKey
• Structural features (general description; literature/structural interpretation):
  • Backbone: A monodisperse PEG chain with approximately 9 ethylene glycol repeats, i.e., –(CH2CH2O)9–.
  • Terminus A: Free thiol (–SH), enabling thiol-specific coupling (e.g., to maleimides, haloacetyls) and surface attachment to coinage metals (Au, Ag) via Au–S.
  • Terminus B: Carboxylic acid (–COOH) appended via a –CH2–CH2– spacer, suitable for carbodiimide activation (EDC/NHS, DIC/HOBt) to couple with primary amines.
  • Functional group summary: thiol, ether (polyether), and carboxylic acid; no stereocenters; flexible, hydrophilic spacer.
• 2D structure in words (literature description): HS–(CH2–CH2–O)×9–CH2–CH2–COOH, linear, unbranched polyether with terminal functionalities at opposite ends.

Synthetic Utility

HS-PEG9-CH2CH2COOH serves as a modular, hydrophilic spacer enabling orthogonal bond formations at each terminus.

• Functional group reactivity (literature/practice):
  • Thiol (–SH):
    • Michael addition to maleimides/acrylates to give thioethers (fast, near-neutral pH).
    • SN2 to haloacetyl or α-halo carbonyls (iodo>bromo>>chloro; base-assisted).
    • Au–S chemisorption for self-assembled monolayers on gold surfaces.
    • Oxidation to disulfide; reversible under reducing conditions.
  • Carboxylic acid (–COOH):
    • Carbodiimide activation (EDC/NHS aqueous; DIC/HOBt organic) to couple with primary amines (amide formation).
    • Conversion to acid chlorides (e.g., oxalyl chloride) is possible but often avoided for PEGs to minimize side reactions.
• Strategic value:
  • Spacer length (PEG9) enhances water compatibility, reduces steric hindrance at binding sites, and can improve target accessibility in immobilized ligands.
  • Orthogonality enables sequential or convergent assembly (e.g., first immobilize via Au–S, then derivatize the terminal –COOH to present ligands on surfaces).
• Practical considerations:
  • Minimize water and oxygen during activation to curb hydrolysis and oxidation.
  • Verify free-thiol content before thiol-specific steps (e.g., Ellman’s assay); reduce disulfides with TCEP if required.
  • Purification by dialysis or SEC can be effective given PEG’s hydrophilicity; reversed-phase or HILIC methods are also used analytically.

Target Specificity

Not applicable. This product is a chemical linker, not a biological targeting reagent (e.g., antibody, inhibitor, or ligand with defined molecular targets). No target, clone, isotype, or species reactivity information is provided or expected.