m-PEG16-COOH , CAS No.2933174-52-6

CAS: 2933174-52-6 Cat. No.: M1445658 Fórmula: C₃₄H₆₈O₁₈ Peso molecular: 764.89

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

Descripción general

m-PEG16-COOH is a PEG-based PROTAC linker that can be used in the synthesis of PROTACs.

Specifications

Condiciones de almacenamiento de almacenamiento

Store at -20°C

Enviado en

Ice chest + Ice pads

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Nombres e identificadores

Peso molecular

764.89

Application Protocols

No item-specific, validated application protocols are provided for this product. For general guidance, see the Reaction Conditions tab for representative coupling procedures (EDC/NHS, CDI, HATU) and adjust to your substrates. Always confirm conditions at small scale and consult the SDS and CoA for handling and quality attributes.

Biological Roles

This section summarizes general, literature-based roles of PEG motifs in biological systems and biotechnology; it does not imply therapeutic use of this item.

• PEG as an inert, hydrophilic spacer

  • PEG chains reduce protein adsorption and immunogenic recognition on material surfaces by creating a highly hydrated, flexible corona.
  • As a crowding agent, PEG alters macromolecular interactions and phase behavior in vitro.

• Functional implications of a terminal carboxyl group

  • The –COOH allows covalent attachment to amine-bearing biomolecules (proteins, peptides, ligands) to introduce a defined hydrophilic spacer length (~16 EO units, literature) while maintaining a non-reactive methoxy cap on the distal end.
  • Carboxylate ionization above pH ~5 confers anionic character that can influence electrostatic interactions and solubility.

• Typical biotechnological uses (research context)

  • Surface passivation of biosensor interfaces and microarrays to minimize nonspecific binding.
  • Creating PEGylated ligands or linkers for affinity capture, diagnostics, and assay development.
  • Stabilization of nanoparticles and colloids in biological buffers by steric hindrance.

• Notes

  • The extent of “stealth” and hydration scales with PEG length; end-group integrity is critical for predictable bioconjugation.
  • All uses are for research only; verify biocompatibility and performance empirically for each system.

Buffer Applications

m-PEG16-COOH is not a pH buffer and is not used to control solution pH. However, in biochemical workflows it may be employed in buffers as a crowding/passivating additive or as a reactant in aqueous coupling.

• As an additive (literature/general)

  • Crowding/anti-fouling: 0.1–10% w/v in PBS, HEPES, or Tris buffers to reduce nonspecific adsorption on surfaces; optimal levels depend on the system.
  • Conjugation medium: carbodiimide couplings commonly use MES buffer (pH 4.7–6.0) for activation, with subsequent coupling near neutral to slightly basic pH (pH 7–8) to enhance amine reactivity.

• Practical notes

  • Maintain ionic strength compatible with the biomolecule and activation chemistry; excessive phosphate can chelate metals used elsewhere in the assay.
  • Avoid primary amine-containing buffers (e.g., Tris) during EDC/NHS activation to prevent side reactions; switch to amine buffers after the activation step.

• Not applicable aspects

  • Classical buffer recipes (pKa, capacity curves) are not applicable to PEG; consult MES, phosphate, or HEPES documentation for precise buffer preparation when used in conjugations.

Green Alternatives

Sustainable use of m-PEG16-COOH focuses on solvent selection and coupling chemistry that reduce hazardous waste without compromising conjugation efficiency.

• Greener media choices (literature/general)

  • Aqueous EDC/NHS coupling in MES or phosphate buffers can replace DMF/DCM-based activations for many amide bond formations, especially when the amine partner is water-compatible.
  • Water/ethanol or water/isopropanol mixtures can solubilize both PEG and moderately hydrophobic substrates, reducing reliance on dipolar aprotic solvents.

• Greener coupling reagents

  • DMTMM (4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium) in water or alcohols offers efficient amide formation with minimal urea byproducts compared to carbodiimides (literature).
  • CDI enables formation of reactive carbonyl imidazolides under milder conditions and avoids urea wastes from EDC/DIC; applicable in greener solvents like 2-MeTHF or CPME when substrates are soluble.

• Solvent comparison (general)

  • DMF/DCM: excellent solvating power but reproductive toxicity/halogenated waste concerns.
  • 2-MeTHF/CPME: bio-based or low-peroxide risk ethers that may dissolve PEG in mixtures; improved safety profile versus THF/MTBE.
  • Water/EtOH: safest profile; feasibility depends on substrate solubility and stability.

• Process tips

  • Employ minimal organic co-solvent fractions, perform reactions at ambient temperature to reduce energy input, and recover/reuse alcohols where feasible.
  • Opt for buffered aqueous workups to avoid excessive saline or halogenated waste.

Pharmaceutical Uses

No clinical or therapeutic claims are made. The following are general, literature-based roles of mPEG-COOH-type materials as excipients or intermediates in pharmaceutical research and manufacturing.

• Excipient/linker roles (general)

  • Hydrophilic spacer for conjugation to APIs, peptides, or targeting ligands during preclinical research to adjust solubility and reduce aggregation (research use only).
  • Surface modification of drug delivery vehicles (e.g., polymeric nanoparticles, liposomes after appropriate anchor chemistry) to impart steric stabilization and reduce protein adsorption.
  • Intermediate for preparing activated esters (e.g., NHS) used in downstream conjugation steps.

• Formulation considerations

  • High aqueous solubility facilitates aqueous processing; viscosity increases with concentration may affect mixing and filtration.
  • Residual solvent and PDI control are important for reproducibility and regulatory assessment in later development stages; item-specific data must be taken from the CoA.

• Analytical control

  • End-group verification (NMR), average MW and PDI (GPC), and residuals (GC/HPLC) are standard quality attributes for PEG excipients.

• Regulatory note

  • PEGs are widely used excipients; however, specifications and compliance (e.g., pharmacopeial monographs) are product- and MW-specific. This listing provides no pharmacopeial designation; consult CoA/specifications for suitability.

Physical Properties

Item-specific physicochemical specifications were not provided for this listing. Where useful, general literature characteristics for mPEG-COOH polymers of similar length (n≈16) are summarized for context only.

• Item-specific values

  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
  • Density, refractive index, UV cutoff, residuals: Not specified for this item; refer to CoA/Spec Sheet.

• General/literature characteristics for mid-range mPEG-COOH (context, not product specs)

  • Physical state: waxy solid or highly viscous semi-solid at ambient temperature, becoming free-flowing upon mild warming.
  • Solubility: highly soluble in water and polar organic solvents (e.g., methanol, ethanol, acetone, DMF, DMSO); limited solubility in nonpolar hydrocarbons (literature, PEG behavior).
  • pKa: terminal carboxyl pKa typically in the 4–5 range depending on linker and medium (literature, carboxylic acids on PEG).
  • Partitioning: very hydrophilic; logP not meaningful for polydisperse polymers; exhibits strong aqueous affinity.
  • Thermal behavior: PEGs show broad softening/melting ranges rather than sharp melting points and do not display a true boiling point before thermal decomposition; glass transition and crystallinity depend on n and thermal history (literature for PEGs).

• Practical notes

  • Viscosity increases rapidly with concentration; warming to 30–40°C can aid dissolution.
  • Hygroscopic tendencies are common for PEGs; handle promptly to minimize water uptake when weighing.

Quality and Grades

• Item-specific grade/purity

  • Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.

• What “grade” means for PEG linkers (general guidance)

  • Polymer conjugation-grade PEGs are typically controlled for average molecular weight, polydispersity index (PDI), residual solvents, and functional end-group conversion. When a product is described as “bioconjugation” or “linker” grade, it often implies high end-group fidelity and low levels of low-MW impurities.
  • Low UV absorbance is advantageous for analytical applications (HPLC/UV), but specific UV specs must be confirmed on the CoA.

• Stabilizers and additives

  • PEGs rarely require stabilizers; however, moisture control is critical. If supplied as a dry solid, no stabilizer is expected. Any inhibitors or residual activating agents (e.g., NHS esters) would be explicitly stated on the CoA; none are specified here.

• Batch documentation

  • Review the CoA for average MW (n), PDI, residual solvent/metal levels, and assay of functional end-group conversion (carboxyl content). End-group verification by NMR or titration is commonly reported in PEG linker CoAs.

• Fit-for-purpose selection

  • For surface chemistry or bioconjugation, prioritize lots with tight MW distribution and verified carboxyl functionality; for materials applications (hydrogel modification, nanoparticle steric stabilization), broader specifications may suffice.

Reaction and Applications

As a monofunctional PEG with a terminal carboxyl group, m-PEG16-COOH serves as a hydrophilic spacer for conjugation and surface modification.

• Bioconjugation and materials modification (general/literature)

  • Amide formation with primary amines on proteins, peptides, polymers, or nanoparticles after in situ activation (EDC/NHS in aqueous buffers; HATU/HBTU in anhydrous DMF).
  • Esterification with alcohols on surfaces or polymer side-chains (DIC/DMAP or CDI activations). Provides stealth characteristics and reduces nonspecific adsorption.
  • Formation of NHS ester intermediates (m-PEG16-NHS) for subsequent rapid amine coupling; typically generated and used immediately to limit hydrolysis.
  • Carbamate/urea linkages via mixed anhydrides or CDI in the presence of amines for specialized linkages.

• Application domains

  • Surface passivation of oxides, metals, and carbon materials (after suitable primer chemistry) to enhance colloidal stability and protein resistance.
  • Spacer in multivalent ligands, biosensors, and polymer therapeutics research (research use only) to control spacing and water compatibility.
  • Hydrogel functionalization to tune swelling and reduce fouling.

• Practical tips

  • Control pH during EDC/NHS activation (pH ~4.7–6) and coupling (pH ~7–8) to balance activation efficiency and amine nucleophilicity (literature guidance).
  • Verify end-group fidelity by 1H NMR (methoxy singlet), carboxyl titration, or MS (for lower-MW distributions) before critical conjugations.
  • Minimize water during organic-phase activations; use freshly dried solvents and exclude base until after activation when required.

Reaction Conditions

The following conditions are general literature guidance for carboxyl-functional PEG conjugations; optimize per substrate. They are not item-specific specifications.

• Aqueous EDC/NHS amide coupling

  • Activation: dissolve m-PEG16-COOH in MES buffer (50–100 mM, pH 4.7–6.0). Add 1.1–2.0 eq EDC and 1.1–2.5 eq NHS relative to –COOH. Stir 5–30 min at 0–25°C.
  • Coupling: adjust to pH 7.0–8.0 and add 1.2–5 eq of amine partner. React 1–4 h at RT (or overnight at 4°C for sensitive biomolecules). Quench excess active ester with Tris or ethanolamine if needed.

• Organic-phase amidation (for poorly water-soluble amines)

  • HATU/DIPEA in dry DMF: 1.1–1.5 eq HATU, 2–4 eq DIPEA, 0–25°C, 1–12 h. Maintain anhydrous conditions to suppress hydrolysis.
  • CDI activation: 1.1–1.5 eq CDI in dry DCM/DMF, 0–25°C, 0.5–2 h to form imidazolide; add amine (1.5–3 eq) with base, 0–25°C, 1–6 h.

• Esterification

  • DIC/DMAP in DCM or DMF: 1.1–2 eq DIC, catalytic DMAP (0.05–0.2 eq), 0–25°C, 2–16 h with alcohol partner.

• Workup and purification

  • Remove urea byproducts (EDC/DIC) by aqueous washes or dialysis for bioconjugates; precipitation into cold diethyl ether or acetone can isolate PEG conjugates.
  • Characterization: 1H NMR (methoxy singlet; disappearance of carboxyl proton if visible), GPC for MW shift; MS applicable for lower dispersities.

• Notes

  • Maintain low temperatures for sensitive biomolecules; avoid primary amine buffers during activation.

Safety and Handling

Hazard classifications for this specific item were not provided; always consult the product SDS for authoritative safety data.

• GHS information (item-specific)

  • Signal word: Not specified for this item; refer to SDS.
  • H-statements: Not specified for this item; refer to SDS.
  • Pictograms: Not specified for this item; refer to SDS.
  • GHS classification: Not specified for this item; refer to SDS.

• General safety profile (literature for PEGs and carboxylic acid-functional PEGs)

  • PEGs are generally of low acute toxicity and low volatility; terminal carboxyl groups may cause mild skin/eye irritation.
  • Not expected to form peroxides (polyethers like PEG are distinct from dialkyl ethers typically implicated in peroxide formation).

• Handling recommendations

  • PPE: lab coat, safety glasses, and suitable gloves (e.g., nitrile). Avoid inhalation of dust/aerosols; handle powders in a fume hood if aerosolization is possible.
  • Incompatibilities: strong oxidizing agents; strong bases/acids may hydrolyze activated esters if generated in situ during coupling steps.
  • First aid (general): rinse eyes/skin with water for several minutes if contacted; seek medical attention if irritation persists. If inhaled, move to fresh air; if ingested, rinse mouth and seek advice.

• Spill and disposal

  • Small spills: collect mechanically; rinse residue with water. Dispose of in accordance with institutional and local regulations.

• Research use

  • For research use only; not for human or veterinary use.

Solvent Selection

m-PEG16-COOH is highly polar and hydrophilic, enabling processing in water and many polar organics. Choice of solvent depends on the coupling chemistry and substrate.

• Polarity and miscibility (general for PEGs)

  • Strongly hydrophilic; miscible with water at typical concentrations.
  • Soluble in polar organics (MeOH, EtOH, acetone, acetonitrile, DMF, DMSO). Limited solubility in nonpolar solvents (hexanes, toluene) unless assisted by co-solvents.

• Selecting a medium by application

  • Aqueous carbodiimide couplings (EDC/NHS): buffers such as MES (pH 4.7–6.0) or phosphate (pH 6–7.2) with 5–20% v/v DMF or DMSO as needed to aid dissolution of hydrophobic partners.
  • Organic amidations/esterifications (DIC/DMAP, HATU, PyBOP): anhydrous DMF, DCM, or NMP; add 0.5–2 eq base (DIPEA) for amide formation when appropriate.
  • Surface grafting on nanoparticles/polymers: use a solvent that swells/solubilizes the substrate (e.g., water/DMF mixtures for polar polymers; IPA/water for oxides).

• Practical notes

  • Remove dissolved oxygen/moisture when forming activated esters (e.g., NHS) to minimize hydrolysis; use dry solvents and inert atmosphere if operating in organics.
  • Viscosity: concentrated PEG solutions can be very viscous; add solvent incrementally and warm gently (≤40°C) to accelerate dissolution.

• Comparisons

  • Water or aqueous-organic mixtures are often preferable to neat DMF/DCM for greener processing, provided substrates are compatible.

Storage and Reconstitution

• Storage (item-specific)

  • Store at −20°C (per product data). Protect from moisture and prolonged exposure to ambient air. Keep container tightly closed.
  • Shipped in an ice chest with ice pads to maintain a cold chain.

• Handling and aliquoting

  • Allow container to equilibrate to room temperature in a desiccator before opening to minimize condensation.
  • If frequent use is anticipated, prepare single-use aliquots under dry conditions and return unused material to −20°C promptly.

• Reconstitution and solvents (general guidance)

  • Highly soluble in water, PBS (avoid amine buffers during activation steps), and polar organics such as DMF and DMSO. Warm gently (≤40°C) and stir to accelerate dissolution; avoid overheating.
  • For moisture-sensitive activation chemistries, use anhydrous solvents and inert atmosphere.

• Stability notes

  • The parent carboxylic acid is typically stable under recommended storage; any activated derivatives (e.g., NHS esters, imidazolides) are moisture-sensitive and should be prepared fresh.

• Shelf-life

  • Not specified for this item; refer to CoA/Spec Sheet. Periodically verify end-group integrity by NMR/titration if material is stored long term.

Structure and Identity

m-PEG16-COOH is a monofunctional polyethylene glycol (PEG) linker featuring a methoxy terminus and a terminal carboxylic acid, with an average of ~16 ethylene oxide (EO) repeat units (literature/general information for mPEG-COOH materials).

• Item-specific identifiers

  • CAS: 2933174-52-6
  • SKU: M1445658
  • Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
  • InChIKey: Not specified for this item; refer to CoA/Spec Sheet.

• Structural features (general/literature for mPEG-COOH)

  • Backbone: poly(ethylene glycol) chain comprising approximately sixteen –CH2–CH2–O– units.
  • Termini: one end capped as a methoxy ether (–OCH3), the other bearing a carboxylic acid (–COOH) or carboxyl functionality via a short linker, enabling amide/ester formation.
  • Functional groups: polyether (multiple C–O–C), terminal carboxylic acid; overall neutral at low pH, anionic as carboxylate at higher pH.
  • 2D description: a flexible, linear polyether chain with repeating ethylene oxide units, methoxy cap on one side, carboxyl group on the opposite end; no defined stereocenters and polydisperse chain length (distribution around n≈16).

• Notes

  • PEG materials are typically reported as an average degree of polymerization; exact chain length distribution and terminal-linker microstructure depend on the manufacturing route. Consult the product CoA for item-specific identity data.

Synthetic Utility

m-PEG16-COOH functions as a monofunctional hydrophilic spacer that introduces PEG character while presenting a single reactive carboxyl terminus.

• Key reactive handle

  • Terminal –COOH enables formation of amides (with amines), esters (with alcohols), and, via activation, anhydrides and imidazolides. The opposing methoxy end is non-reactive, ensuring monofunctionality.

• Named/standard transformations (literature)

  • EDC/NHS-mediated amide coupling in water or mixed aqueous–organic media.
  • DIC/DMAP esterification in aprotic organics; CDI activation to PEG–O–(C=O)–Im intermediates followed by nucleophilic substitution.
  • HATU/HBTU/TBTU couplings in anhydrous DMF or NMP for challenging amine partners.

• Retrosynthetic value

  • Serves as a modular PEG spacer between a carboxyl-derived linkage and a distal methoxy-capped end, useful in designing amphiphilic constructs, surface ligands, and linkers with defined hydrophilicity.

• Practical considerations

  • Confirm absence of di-functional PEG impurities to prevent crosslinking; check PDI and end-group conversion on the CoA.
  • For surface work, pre-functionalize substrates with amines (e.g., silanization on oxides) to enable amide formation.
  • Control stoichiometry to avoid over-activation and minimize O→N acyl transfer side products in peptide contexts.

Target Specificity

Not applicable. m-PEG16-COOH is a small-molecule/polymer linker, not a biological affinity reagent or antibody. No antigen, clone, or species reactivity information applies.

Preguntas frecuentes

How should this product be stored?

Store at ?20 °C. Freezer storage is required to maintain the specified shelf life.

How is this product shipped?

This product ships in an insulated container with ice pads. Unpack on arrival and transfer it to the storage condition stated above.

What are the CAS number, molecular formula and molecular weight?

The CAS Number is 2933174-52-6, the molecular formula is C34H68O18, and the molecular weight is 764.89 g/mol.

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.