mPEG benzaldehyde - MW 10000 Da

Cat. No.: M163981

GRADE & PURITY MW 10000 Da

Storage

Room temperature

Shipped In

Normal

Specifications

Spécifications et pureté

MW 10000 Da

Conditions de stockage de stockage

Room temperature

Expédié en

Normal

Application Protocols

No item-specific, validated application protocols are provided for this product. Refer to the Reaction Conditions, Buffer Applications, and Synthetic Utility sections for general, literature-based guidance on using mPEG benzaldehyde in ligation and conjugation workflows. Users should optimize stoichiometry, pH, solvent composition, and reaction time for their specific substrates and analytical methods.

Biological Roles

Item-specific biological data: Not specified for this item; refer to CoA/Spec Sheet. The product is for research use only.

General/literature context:

• PEG as a biomaterials component: Poly(ethylene glycol) is widely used to reduce protein adsorption, extend circulation of materials, and improve hydrophilicity due to its flexible, hydrophilic polyether backbone.
• Aldehyde end-group reactivity: The benzaldehyde terminus reacts with primary amines (e.g., ε-lysine on proteins) to form Schiff bases. In bioconjugation workflows, the resulting imines are often reduced in situ to secondary amines for stability, or oximes/hydrazones are formed using aminooxy/hydrazide-functional biomolecules.
• Selectivity considerations: Under mildly acidic conditions (pH ~5–6), reaction with amines is favored while minimizing competing hydrolysis; aniline catalysis can increase rates for oxime/hydrazone formation without harsh conditions.
• Applications in biointerfaces: Aldehyde-terminated PEGs are commonly used to decorate surfaces (particles, hydrogels, microarrays) to present functional handles for ligand immobilization while maintaining non-fouling characteristics of the PEG matrix.

No claims are made regarding therapeutic, diagnostic, or clinical performance. This information is intended to guide research use and experimental design.

Buffer Applications

While mPEG benzaldehyde is not itself a buffering agent, buffer choice is critical for its conjugation chemistry (literature/general guidance):

• Imine formation with primary amines:
  • Recommended buffers: sodium acetate or MES, pH 5.0–6.0; avoid primary amine-containing buffers (e.g., Tris) that compete with conjugation.
  • Typical conditions: 10–100 mM buffer, room temperature to 37 °C, 1–24 h; optional 5–10% DMF/DMSO to aid polymer solubility.
• Oxime ligation with aminooxy groups:
  • Buffers: acetate or citrate, pH 4.5–5.5; aniline (10–100 mM) as a nucleophilic catalyst can significantly accelerate the reaction.
• Hydrazone formation with hydrazides:
  • Buffers: acetate, pH 4.5–5.5; subsequent reduction to hydrazide-linked amine for permanence if required.
• Reductive amination (to stabilize imines):
  • Buffers/solvents: aqueous acetate (pH ~5.5) with EtOH/MeOH co-solvent; reducing agents such as picoline borane or NaBH3CN. Maintain low free ammonia/amine background.

Practical notes:

• Degas buffers if working with oxygen-sensitive partners; minimize metal contaminants if downstream assays are metal-sensitive.
• Filter-sterilize and use freshly prepared buffers to limit aldehyde oxidation and bioburden during bioconjugation.

Green Alternatives

Greener practice considerations focus on solvent choice, catalysts, and reducing agents rather than replacing the aldehyde functionality, which is central to performance.

• Prefer aqueous media: conduct imine/oxime/hydrazone ligations in water or buffered water (acetate, MES) with minimal co-solvent (≤10% DMF/DMSO/EtOH) when biomolecule stability allows.
• Catalysis: aniline or p-phenylenediamine catalysts at low mol% can accelerate oxime/hydrazone formation at room temperature, reducing energy input.
• Reducing agents: switch from sodium cyanoborohydride to picoline borane or pyridine–borane in aqueous ethanol or acetate buffer to avoid cyanide-containing waste (literature).
• Workup/purification: use precipitation, dialysis, or ultrafiltration instead of chlorinated solvent chromatography where possible.

Comparison of options (literature/general; qualitative):

• Aqueous acetate buffer (pH 5.0) vs anhydrous MeOH/THF
  • Pros: minimal VOCs, benign waste, compatible with biomolecules
  • Cons: possible aldehyde hydration; slower kinetics without catalyst
• Picoline borane vs NaBH3CN
  • Pros: avoids cyanide, effective in protic media
  • Cons: can be less reactive toward hindered imines; may require higher equivalents
• EtOAc/IPA for precipitation vs DCM-based workups
  • Pros: lower toxicity/ozone impact
  • Cons: may need optimization for complete recovery of PEG conjugates

Note: No direct “green replacement” for the benzaldehyde handle delivers the same conjugation profile; performance tradeoffs must be considered.

Pharmaceutical Uses

Item-specific pharmacopeial status or excipient grade: Not specified for this item; refer to CoA/Spec Sheet. For research use only.

General/literature context for PEG derivatives in pharmaceutical development (non-clinical, formulation/manufacturing perspective):

• PEGylation reagent: Benzaldehyde-terminated mPEG is used in process development to covalently attach PEG to amine-bearing biomolecules (proteins, peptides) or to surfaces, typically by imine formation and in situ reduction, to modulate solubility, stability, and processability.
• Materials and device coatings: Aldehyde-PEGs can be grafted onto particles, stents, or hydrogel matrices to present ligands while maintaining low-fouling PEG surfaces.
• Excipient considerations: For any GMP-intended use, specifications typically include average MW, Đ, residual solvents/metals, bioburden/endotoxin (if applicable), and end-group functionality (mol% aldehyde). These parameters impact consistency and safety profiles of final products.
• Regulatory perspective: When used as a processing aid or intermediate in R&D, documentation focuses on synthetic route, impurity controls, and absence of reactive residuals in the final API or device. Transition to GMP supply requires validated analytical methods for MW distribution and end-group assay.

No therapeutic or clinical claims are made. End-use suitability must be established by the user under relevant regulatory frameworks.

Physical Properties

Item-specific properties (this lot):

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Average Molecular Weight (Mn or Mw): Not specified for this item; refer to CoA/Spec Sheet.
• Density, refractive index, UV cutoff, residuals (water/metals/peroxides): Not specified for this item; refer to CoA/Spec Sheet.

General/literature characteristics for mPEG–benzaldehyde (informational; not product specifications):

• Physical form: typically a white to off-white solid or viscous wax, depending on average MW (lower MW → waxy liquids/soft solids; higher MW → free-flowing solids).
• Solubility: highly soluble in water, methanol, ethanol, DMSO, DMF; good solubility in many polar aprotic solvents; limited solubility in nonpolar hydrocarbons. Aromatic end-group slightly enhances solubility in moderately polar organics.
• Hygroscopicity: PEG chains are hygroscopic and absorb moisture; aldehydes can form hydrates in aqueous media.
• Vapor pressure: negligible for polymeric PEGs (literature).
• Glass transition (Tg) and melting behavior: broad transitions that depend strongly on MW and dispersity; low-MW mPEGs often show melting in the 30–60 °C range; higher MWs melt above 60 °C (literature, typical ranges only).
• Partitioning: PEG backbone confers hydrophilicity; aromatic aldehyde increases interfacial adsorption to hydrophobic surfaces relative to unfunctionalized mPEG (qualitative literature observation).

Note: Exact numerical values (BP/MP/logP/pKa) are not defined or not meaningful for polydisperse PEGs; consult the CoA for this item’s MW and any measured properties.

Quality and Grades

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

Context for PEG derivatives (general/literature guidance):

• PEG polymer quality is defined by average molecular weight (Mn or Mw), polydispersity index (Đ), end-group functionality (aldehyde content, typically reported as mol% functionalization), and residuals (water, solvents, catalysts, monomer traces). For aldehyde-PEGs, end-group fidelity is critical for predictable conjugation stoichiometry.
• Typical analytical controls: 1H/13C NMR to verify aldehyde resonance and end-group integration; MALDI-TOF or GPC/SEC for MW and Đ; FTIR for carbonyl band; titration or derivatization assays to quantify reactive aldehyde content; Karl Fischer for moisture.
• Grades you may encounter:
  • “Bioconjugation/functional” grade: controlled Đ with high end-group fidelity; low residuals; often supplied dry under inert atmosphere.
  • “Research” grade: suitable for general synthesis; specifications may be broader.
  • HPLC grade does not apply to polymers per se; instead, low-UV and low-fluorescent impurity profiles are sometimes specified for bioanalytics.

Implications for this item: without a stated grade, verify end-group content, MW distribution, and residual solvent/water on the CoA before sensitive conjugations or analytical work.

Reaction and Applications

This benzaldehyde-terminated mPEG is a versatile platform for chemoselective ligation and surface/bio-conjugation.

Key application areas (literature/general):

• Imine (Schiff base) ligation to primary amines on proteins, peptides, and small molecules; reversible at equilibrium but can be stabilized by reduction to secondary amines (reductive amination) using NaBH3CN, picoline borane, or NaBH(OAc)3.
• Oxime ligation to aminooxy-functional partners (–ONH2): forms oximes with improved hydrolytic stability; efficient at mildly acidic pH (≈4.5–5.5), optionally aniline-catalyzed.
• Hydrazone formation with hydrazides: convenient for carbohydrate and surface conjugation; stability enhanced at lower pH or by subsequent reduction.
• Material/surface modification: end-functional PEGylation of nanoparticles, hydrogels, and interfaces to impart stealth/hydrophilicity while presenting an aldehyde handle for further attachment.
• Polymer chemistry: serves as an initiator/macromonomer in step-growth routes where the benzaldehyde is subsequently transformed (e.g., to benzyl alcohol under NaBH4 or to benzoic acid under mild oxidation) to vary end-group polarity.

Practical tips:

• Maintain low water content for small-molecule syntheses to suppress hydrate formation; for bioconjugation, controlled aqueous conditions are acceptable.
• Use slight molar excess of aldehyde-PEG to drive conjugations; monitor by 1H NMR (imine CH ~8–9 ppm), LC-MS of small partners, or SEC for bioconjugates.
• Protect from prolonged basic conditions; imines hydrolyze less at mildly acidic pH.

Reaction Conditions

General literature guidance for typical transformations (not product specifications):

• Imine (Schiff base) formation with primary amines:

  • Solvent/buffer: sodium acetate or MES, pH 5.0–6.0; 0–10% DMF/DMSO to aid solubility.
  • Conditions: 20–37 °C, 1–24 h; use 1.1–2.0 equiv of mPEG–benzaldehyde vs amine.
  • Notes: Avoid amine-containing buffers (Tris, glycine). Remove dissolved oxygen if oxidation is problematic.

• Reductive amination (to stabilize imines):

  • Reagents: NaBH3CN (acetic buffer/MeOH), picoline borane (water/EtOH), or NaBH(OAc)3 (DCM/MeCN for small molecules).
  • Conditions: room temperature to 37 °C; 2–6 h (small molecules) to overnight (bioconjugation). Maintain mildly acidic pH (~5.5–6.0) for cyanoborohydride in water/alcohol.

• Oxime ligation (aminooxy partners):

  • Buffer: acetate or citrate, pH 4.5–5.5; 10–100 mM aniline catalyst optional.
  • Conditions: RT; 0.5–4 h with catalyst, longer without; aqueous with up to 20% co-solvent.

• Hydrazone formation (hydrazides):

  • Buffer: acetate pH 4.5–5.5; reduction after ligation for permanence.

• Aldehyde reduction to alcohol (small-molecule transformations of the end-group):

  • Reagents: NaBH4 in MeOH/EtOH at 0–25 °C; quench cautiously; isolate by precipitation into ether/acetone.

Monitor reactions by 1H NMR (aldehyde ~9.8–10.1 ppm; imine ~8–9 ppm), SEC, or MS of the small-molecule partner. Optimize temperature and equivalents based on substrate sterics and desired kinetics.

Safety and Handling

Item-specific hazard data:

• Signal Word: Not specified for this item; refer to SDS.
• H-Statements / GHS Classification / Pictograms: Not specified for this item; refer to SDS.

General safety considerations (literature/general guidance; not a substitute for the SDS):

• Expected hazards: PEG backbones are of low acute toxicity; the benzaldehyde end-group is an electrophile that can irritate eyes/skin and react with primary amines. Avoid inhalation of dusts/aerosols and prolonged skin contact.
• PPE: lab coat, safety glasses, and appropriate chemical-resistant gloves (e.g., nitrile). Use in a fume hood when handling powders/solutions, especially in volatile organic solvents.
• Incompatibilities: strong oxidizers (may oxidize aldehyde to benzoic acid derivatives), strong bases (can accelerate aldol-type side reactions or imine formation), strong reducing agents (could reduce the aldehyde). Avoid prolonged exposure to acids/bases at elevated temperature unless intended for conjugation.
• Special risks for aldehydes: prone to hydration and Schiff base formation; can slowly oxidize on air/light. Keep containers tightly closed to minimize moisture and oxygen exposure.
• First aid (overview): in case of skin or eye contact, rinse with plenty of water for at least 15 minutes; if inhaled, move to fresh air; if swallowed, rinse mouth. Seek medical attention as appropriate.

Always consult the product’s SDS for authoritative hazard, handling, spill, and disposal instructions. For research use only.

Solvent Selection

Practical solvent guidance for mPEG benzaldehyde (general/literature):

• Polarity class: amphiphilic polymer—hydrophilic PEG backbone with a moderately hydrophobic aromatic aldehyde end.
• Miscibility/solubility: readily soluble in water and polar organics (MeOH, EtOH, isopropanol, acetone, acetonitrile), as well as high-boiling polar aprotics (DMF, DMSO, NMP). Limited in nonpolar alkanes; better in ethyl acetate, dichloromethane, or THF. For conjugations, aqueous buffers (acetate, MES, phosphate) with 5–30% co-solvent (DMF/DMSO/EtOH) often balance solubility and biomolecule stability.
• Selection tips:
  • For Schiff base/oxime/hydrazone formation with biomolecules: use mildly acidic buffers (pH ~4.5–6) such as acetate or MES; add 5–10% DMF or DMSO if needed to fully dissolve the polymer.
  • For reductive amination with small molecules: anhydrous MeOH, EtOH, or THF with NaBH3CN or picoline borane; DMF or MeCN for less soluble partners.
  • For purification: precipitation from cold diethyl ether or acetone is commonly used to isolate PEG conjugates; dialysis or spin ultrafiltration for bioconjugates.

Comparison (literature/general):

• vs unfunctionalized mPEG: similar solubility, but aldehyde end increases affinity for moderately polar organics.
• vs aliphatic aldehyde-PEGs: benzaldehyde end-groups are less prone to self-aldol and often more stable, while remaining reactive toward amines/oximes.

Storage and Reconstitution

Item-specific storage and shipping:

• Storage Conditions: Room temperature (per product data). Keep container tightly closed.
• Shipped In: Normal (ambient) conditions (per product data).
• Research Use Note: For research use only.

Best practices (literature/general guidance):

• Protection: Store in a dry, dark place under inert gas if possible. The aldehyde end-group is sensitive to oxidation and hydration; minimize exposure to air and moisture. Include desiccant in secondary packaging.
• Stability: PEG backbone is robust; aldehyde may slowly oxidize to the corresponding benzoic acid over time—verify end-group content before critical conjugations.
• Handling: Warm gently (≤40 °C) to aid dissolution if waxy/solid. Use dry tools/solvents to avoid hydrate formation for small-molecule syntheses; for bioconjugation, freshly prepared aqueous buffers are acceptable.
• Reconstitution: Dissolve to 5–100 mg/mL depending on application in water, PBS (avoid for imine formation due to pH/amine content), acetate/MES buffers, or organic solvents (MeOH, EtOH, DMF, DMSO). Filter (0.22 µm) for bioconjugation to remove particulates.
• Freeze–thaw: Typically not required; if storing solutions, aliquot and freeze at −20 °C to minimize degradation. Avoid repeated freeze–thaw cycles.

Always consult the product’s CoA/SDS for definitive handling, stability, and safety information.

Structure and Identity

mPEG benzaldehyde is a heterobifunctional polyethylene glycol derivative featuring a non-reactive methoxy cap (–OCH3) at one terminus and an aromatic aldehyde (–CHO on a benzene ring) at the other terminus. The benzaldehyde end group enables chemoselective conjugation to nucleophiles (e.g., primary amines, aminooxy, hydrazides) via reversible imine/oxime/hydrazone linkages that can be stabilized or reduced to permanent C–N bonds.

• Item-specific identifiers

  • CAS: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Formula: Not specified for this item; refer to CoA/Spec Sheet (PEGs are polydisperse; formula depends on average MW).
  • Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet (typically reported as an average, e.g., Mn).
  • SMILES / InChIKey: Not specified for this item; refer to CoA/Spec Sheet (polymeric; end-group structures vary by supplier design).

• Structural features (general description; literature/general knowledge)

  • Backbone: linear –[CH2–CH2–O]n– polyether chain with low polydispersity (typical for mPEG grades).
  • End groups: one terminus capped with methoxy; the other terminus displays an aromatic benzaldehyde (benzene bearing a formyl group).
  • Functional group chemistry: aldehyde carbonyl electrophile; PEG ether oxygens impart high hydrophilicity and organic solvent compatibility.
  • Stereochemistry: none intrinsic to the repeating unit; polymer is atactic and polydisperse.

• 2D description in words: a linear poly(ethylene oxide) chain capped by methoxy at one end and a phenyl ring bearing –CHO at the other end (mPEG–Ph–CHO or equivalent benzaldehyde-presenting linkage depending on design).

Synthetic Utility

Chemoselective functionality and amphiphilicity make mPEG benzaldehyde a valuable macromolecular synthon (literature/general):

• Electrophilic handle: the benzaldehyde terminus undergoes nucleophilic addition–elimination with amines to form imines; with aminooxy/hydrazides to give oximes/hydrazones. Post-reaction reduction provides robust secondary amines.
• Diversity enabling: couples readily to amine-bearing small molecules, linkers, dyes, chelators, and biomolecules; facilitates installation of PEG for solubility modulation and stealth.
• Transformations of the aldehyde:
  • Reduction to benzyl alcohol (NaBH4, DIBAL) enabling further esterification/etherification.
  • Oxidation to benzoic acid (TEMPO/bleach variants, Pinnick oxidation conditions adapted to PEG) for amide coupling.
  • Formation of acetals/ketals as protecting groups or to introduce acid-labile linkages.
• Polymer architecture: serves as a monofunctional PEG macroinitiator/chain stopper in step-growth or click-based elaborations after converting the aldehyde to other handles (e.g., azide/alkyne via benzyl alcohol → tosylate → azide).
• Purification leverage: PEGylated products often precipitate from cold ether/acetone or are isolable by aqueous workup due to phase behavior, simplifying separation from non-PEGged byproducts.

These attributes enable retrosynthetic strategies where a single PEG installation solves multiple constraints: solubility, bioconjugation, and purification.

Target Specificity

Not applicable. This product is a functional polymer reagent (mPEG benzaldehyde), not a biological targeting molecule or antibody. No antigen/epitope/clone/isotype information is associated with this item.

Foire aux questions

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 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.