This compound belongs to the class of organic compounds known as benzoic acids. These are organic Compounds containing a benzene ring which bears at least one carboxyl group.
External Descriptors
Not available
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.
Certificati (CoA, COO, BSE/TSE e tabella di analisi)
C of A & Other Certificates(BSE/TSE, COO):
Analytical Chart:
Proprietà chimiche e fisiche
Peso molecolare
192.250 g/mol
XLogP3
3.300
Hydrogen Bond Donor Count
1
Hydrogen Bond Acceptor Count
2
Rotatable Bond Count
1
Exact Mass
192.115 Da
Monoisotopic Mass
192.115 Da
Topological Polar Surface Area
37.300 Ų
Heavy Atom Count
14
Formal Charge
0
Complexity
208.000
Isotope Atom Count
0
Defined Atom Stereocenter Count
0
Undefined Atom Stereocenter Count
0
Defined Bond Stereocenter Count
0
Undefined Bond Stereocenter Count
0
The total count of all stereochemical bonds
0
Covalently-Bonded Unit Count
1
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Recensioni
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Application Protocols
Not applicable. No biologically validated application protocols (e.g., WB, IHC, IF, FC) are associated with this small-molecule reagent. For practical use, refer to the Synthetic Utility and Reaction Conditions sections for representative chemical procedures.
Biological Roles
This product is intended for research and laboratory use only. No clinical or therapeutic claims are made.
General biochemical context (literature/general)
Pentamethylbenzoic acid is a heavily alkylated benzoic acid with no established endogenous biological role. It is not a known metabolite in primary metabolism. The five methyl groups enhance lipophilicity and steric bulk, which can be useful in structure–property studies of transport, partitioning, and protein–ligand sterics when used as a probe or as part of synthetic intermediates.
Carboxylic acids can form salts and co-crystals; derivatives of bulky benzoic acids are sometimes explored as co-formers in crystal engineering studies of organic solids.
Use in biochemical experiments (general)
As a hydrophobic acid, it can serve as a model for studying membrane partitioning, protein binding to aromatic carboxylates, or enzyme selectivity toward sterically hindered acyl donors when converted to activated esters.
Cautions
Not a buffer component and not designed for cellular media preparation. If used in biological assays, ensure appropriate solvent vehicles (e.g., DMSO co-solvent at low percentages) and confirm compatibility with assay conditions.
For any biological handling, consult the SDS and institutional biosafety policies.
Buffer Applications
Pentamethylbenzoic acid is not typically used as a buffering agent. Aromatic monocarboxylic acids with pKa values near 4–5 provide limited buffering capacity in the physiological range and have low aqueous solubility.
Practical guidance
If a carboxylate buffer near pH 4–5 is required, standard systems such as acetate (pKa 4.76), citrate (multi-pKa), or phthalate buffers are preferred.
For work with pentamethylbenzoic acid itself, aqueous solutions are not common; operations are typically conducted in organic solvents or biphasic systems with base to form the soluble carboxylate.
For precise buffer recipes and pH ranges, consult appropriate buffer references; this product is better suited to synthetic applications outlined in the Synthetic Utility and Reaction & Applications sections.
Green Alternatives
While pentamethylbenzoic acid is a solid building block rather than a bulk solvent, greener decisions center on solvent choice, activating reagents, and waste minimization in its transformations.
Greener solvent choices (general/literature)
Prefer ethyl acetate, 2-MeTHF, CPME, or toluene over chlorinated solvents where possible. For couplings, dimethyl carbonate or propylene carbonate can sometimes replace DMF/NMP when combined with catalytic nucleophilic acyl transfer promoters (e.g., DMAP).
In esterifications, use azeotropic water removal in toluene or bio-derived solvents (2-MeTHF) instead of strong mineral acids in MeOH/CH2Cl2 workups.
Reagent selection
Avoid stoichiometric carbodiimides when possible; catalytic acyl transfer strategies (e.g., imidazolide intermediates from CDI) can reduce urea waste. Enabling mixed anhydrides (e.g., isobutyl chloroformate) may simplify byproducts.
For decarboxylative couplings, visible-light photoredox with organic dyes (e.g., 4CzIPN) can replace precious-metal catalysts in some cases.
Comparison snapshot (general)
DCM vs. EtOAc: EtOAc is less hazardous, biodegradable, and often provides comparable solubility for acylation workups.
DMF vs. 2-MeTHF: 2-MeTHF improves EHS profile and distills readily; however, DMF may be required for challenging couplings due to polarity.
Process intensification
Employ solvent recycling, in-line water removal, and solid-supported reagents (e.g., PS-DMAP) to reduce waste.
In crystallizations, design antisolvent systems to minimize solvent volumes and enable recovery.
Note: These are general green chemistry considerations; adapt to your substrate set and regulatory context.
Pharmaceutical Uses
No pharmacopeial or excipient status is provided for this item. This product is supplied for research use only.
General formulation context (literature/general)
Pentamethylbenzoic acid is primarily a synthetic intermediate. Its bulky benzoyl group can be introduced into small molecules as an acyl moiety (esters/amides) to modulate lipophilicity, metabolic stability, or crystallization behavior during lead optimization studies.
Carboxylic acids of this class can act as co-formers for salt or co-crystal screening in preformulation research, although pentamethyl substitution may limit hydrogen-bonding patterns compared to polyfunctional acids.
Manufacturing considerations
If used as an intermediate, ensure reagents/solvents meet ICH Q3A/B expectations for impurity control; residual solvents should be controlled per ICH Q3C.
Downstream removal of urea byproducts (from DCC) and elimination of chlorinated solvent residues are common process concerns.
Regulatory note
This material is not intended for human or veterinary drug use. No therapeutic claims are made. Any application in a regulated context would require independent qualification of specifications and suppliers.
Physical Properties
Only limited item-specific physical constants are provided in the Product Data. Values below are general literature guidance for pentamethylbenzoic acid and must not be treated as product specifications.
Item-specific values
Appearance: Not specified for this item; refer to CoA/Spec Sheet.
Molecular weight (item): Not specified for this item; refer to CoA/Spec Sheet.
Melting point: commonly reported in the mid- to high-160s °C range (literature; exact value varies by source and purity)
Boiling point: high; carboxylic acids of this class often decompose before distillation (literature)
Density: not widely tabulated; expected near ~1.0–1.2 g/cm3 for substituted benzoic acids (qualitative, literature trend)
Solubility: low in water; soluble in common organic solvents (e.g., dichloromethane, chloroform, toluene, THF, acetone, methanol/ethanol to varying degrees) (literature)
LogP: expected higher than benzoic acid due to five methyls (literature qualitative trend)
Refractive index: not applicable (solid)
Notes
For exact item values (mp, water content, residual solvents, metal content, UV cutoff, etc.), consult the CoA/Spec Sheet. Do not use literature values as acceptance criteria for this SKU.
Quality and Grades
Item-specific grade/purity
Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet for actual assay, residual solvent, and impurity profile.
Appearance: Not specified for this item; refer to CoA/Spec Sheet.
How to interpret common grades (general guidance)
Analytical Reagent (AR) or ≥98–99%: suitable for most synthetic applications; impurities typically limited but not necessarily controlled for trace metals.
HPLC grade (for solvents) vs. synthetic intermediates: for solids like aromatic acids, “high purity” often emphasizes low non-volatile residue, tight melting range, and low aromatic impurities.
Catalysis-grade/trace-metals screened: relevant if the acid will be converted to acid chloride and used in metal-catalyzed steps (e.g., acylations, cross-couplings). If metal limits matter for your workflow, request trace-metals data on the CoA.
Stabilizers/additives
None are typically required for benzoic acids; no inhibitor is expected unless stated. If any stabilizer is used, it will appear on the CoA.
What to verify on receipt (practical tips)
Confirm identity by 1H/13C NMR (distinct five methyl singlets or near-singlets depending on symmetry; carboxyl carbon ~170–175 ppm), IR (broad O–H, strong C=O ~1680–1720 cm−1), and HRMS.
Check melting range against the CoA; use HPLC/GC to assess aromatic/alkyl aromatic impurities if your downstream step is sensitive to trace isomers.
Reaction and Applications
As a sterically encumbered, electron-rich benzoic acid, pentamethylbenzoic acid is a valuable building block for preparing bulky benzoyl derivatives and for probing steric/electronic effects in acylation chemistry and decarboxylative transformations.
Representative applications (literature/general)
Acid chloride synthesis: conversion to pentamethylbenzoyl chloride with SOCl2 or (COCl)2 (cat. DMF). The resulting acyl chloride is a versatile acylating agent for alcohols, amines, and aromatics (Friedel–Crafts acylation) to install a highly hindered benzoyl group.
Ester and amide formation: via Fischer esterification (ROH, acid catalysis) or coupling (DCC/EDC + DMAP/HOBt) to form sterically demanding esters/amides with modulated stability and reduced susceptibility to hydrolysis.
Mixed anhydrides and activated esters: formation of NHS or NHPI esters enables mild acyl transfer or decarboxylative cross-coupling (photoredox/Ni). The bulky aryl group can attenuate side reactions.
Decarboxylative functionalization: silver-, copper-, or photoredox-mediated decarboxylation to access pentamethyl aryl radicals/cations for C–C and C–X bond formation (e.g., Minisci-like or cross-coupling via redox-active esters).
Salt formation and crystallization aids: carboxylate salts with organic bases (e.g., DBU, TMG) serve as bench-stable intermediates or aid in separations.
Practical notes
Steric hindrance may slow acylation of hindered nucleophiles; use more reactive activators (acyl chloride, mixed anhydride) or catalysts (DMAP) and elevate temperature where compatible.
Ensure rigorously anhydrous conditions for acyl chloride generation and store derivatives under inert atmosphere to prevent hydrolysis.
For photoredox decarboxylations, consider preparing the NHPI (phthalimide) ester; blue LEDs, Ir(ppy)3 or fac-Ir(ppy)3-type catalysts, and Ni co-catalysts are commonly reported (literature guidance).
Reaction Conditions
The following are general literature-style conditions for common operations on pentamethylbenzoic acid; they are not specifications for this SKU.
Acid chloride formation
Reagents: thionyl chloride (SOCl2, 3–5 equiv) or oxalyl chloride ((COCl)2, 1.5–2.0 equiv) with 0.05–0.10 equiv DMF as catalyst.
Solvent: DCM or toluene; temperature 0 °C to reflux depending on reagent; 1–4 h typical. Remove volatiles under reduced pressure; keep product dry/inert.
Steglich esterification (hindered alcohols)
Reagents: DCC (1.1–1.3 equiv), DMAP (0.1 equiv). Solvent: DCM or DCM/DMF (anhydrous). Temperature: 0 °C to rt, 2–16 h. Filter dicyclohexylurea; purify by chromatography or crystallization.
Amide coupling
Reagents: EDC·HCl (1.2–1.5 equiv) + HOBt or Oxyma and DIPEA; solvent: DMF/DCM or 2-MeTHF (when feasible). Temperature: rt to 40 °C; 2–18 h. Bulky acyl donor may require higher catalyst loading.
Fischer esterification
Conditions: ROH (excess), catalytic H2SO4 or p-TsOH, reflux; remove water (Dean–Stark with toluene for higher alcohols). Times: 2–12 h depending on alcohol.
Decarboxylative coupling (via NHPI ester)
Activation: DIC or EDC to form NHPI ester in DCM/DMF. Coupling: photoredox catalyst (e.g., Ir(ppy)3, 0.5–2 mol%), Ni co-catalyst (1–10 mol%), base (e.g., Cs2CO3), blue LEDs, rt to 40 °C, 2–24 h. Substrate-dependent yields.
Workup/purification tips
Carboxylic acids/esters often crystallize from toluene/hexanes or EtOAc/hexanes. Control temperature ramps to narrow particle-size distribution. Neutral/acid/base washes help remove coupling reagents and urea byproducts.
Note: Optimize stoichiometries and conditions for your substrate set; monitor by TLC/HPLC/LC–MS.
Safety and Handling
Safety information specific to this SKU is not fully provided in the Product Data; treat guidance below as general best practice for aromatic carboxylic acids and defer to the product SDS for authoritative details.
GHS classification and hazard statements
Signal word / H-Statements / Pictograms: Not specified for this item; refer to SDS.
General expectation (literature/general): aromatic carboxylic acids are typically classified as eye/skin irritants; dust may cause respiratory irritation.
Use in a chemical fume hood to minimize dust inhalation.
Wear appropriate PPE: lab coat, safety glasses, and chemical-resistant gloves (e.g., nitrile). Avoid generating dust and avoid contact with eyes/skin.
Avoid contact with strong bases (forms salts) and strong oxidizers. Mildly corrosive to reactive metals in the presence of moisture due to acidity.
First aid (general overview; consult SDS)
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; obtain medical advice if irritation continues.
Ingestion: rinse mouth; do not induce vomiting; seek medical help.
Fire and reactivity
Combustible organic solid; use water spray, dry chemical, CO2, or foam for extinguishing. Thermal decomposition may produce CO/CO2.
Not prone to peroxide formation.
Storage conditions (from Product Data)
Store at room temperature, tightly closed, in a dry, well-ventilated place. Segregate from strong oxidizers and strong bases. Always follow institutional chemical hygiene procedures.
Solvent Selection
Pentamethylbenzoic acid is a lipophilic aromatic carboxylic acid with low aqueous solubility and good compatibility with many organic solvents. Choice of solvent depends on the target operation (esterification, amidation, acid chloride formation, or crystallization).
Polarity and miscibility (general/literature)
Poorly soluble in water; enhanced solubility in moderately polar aprotic and nonpolar aromatic solvents: dichloromethane (DCM), chloroform, THF, dioxane, acetone, ethyl acetate, toluene, xylene. Alcohols (MeOH/EtOH/iPrOH) dissolve it to varying degrees; bases (e.g., NaOMe) form soluble carboxylate salts in alcohols/water.
As a carboxylic acid, solubility increases in basic aqueous media via deprotonation.
Typical use scenarios
Acid chloride formation: DCM or toluene with SOCl2 or (COCl)2 and catalytic DMF; dry conditions.
Esterification (Fischer): refluxing ROH with catalytic acid (H2SO4/p-TsOH) and water removal (Dean–Stark for higher alcohols/toluene co-solvent; simple reflux for MeOH/EtOH).
Carbodiimide couplings (amide/ester): DCM, DMF, or DCM/DMF with DCC/EDC and an additive (HOBt/HOAt/DMAP).
Crystallization: often from toluene, hexanes/EtOAc mixtures, or EtOH/Water antisolvent systems depending on desired particle form.
Practical comparisons (general)
DCM vs. toluene: DCM offers faster acyl chloride formation at lower temperatures; toluene enables higher-temperature drives and easier Dean–Stark in esterifications.
DMF promotes coupling but is harder to remove; EtOAc is greener and simplifies work-up when feasible.
Storage and Reconstitution
Storage (from Product Data)
Store at room temperature. Keep container tightly closed in a dry, well-ventilated place. Protect from moisture and strong oxidizers/bases. Follow standard chemical hygiene practices.
Stability (general)
Aromatic carboxylic acids are typically stable solids under ambient conditions. Avoid prolonged exposure to strong light/heat that may promote discoloration or slow oxidation of methyl groups.
Reconstitution/solution preparation (general guidance; not a specification)
Pentamethylbenzoic acid dissolves in many organic solvents: DCM, chloroform, toluene/xylene, THF, acetone, ethyl acetate, and alcohols to varying extents. Prepare stock solutions under anhydrous conditions if subsequent steps are moisture sensitive (e.g., acyl chloride formation).
For aqueous manipulations, dissolve with a minimal amount of organic co-solvent or convert to a water-soluble salt by adding a stoichiometric base (e.g., NaHCO3, NaOH) in a biphasic system.
Packaging/shipping
Shipped conditions: Not specified for this item; refer to product label. In general, ship/store as a stable organic solid at ambient temperature.
CoA/SDS
For exact storage life, assay, and handling specifics for SKU P1072589, consult the current Certificate of Analysis and Safety Data Sheet.
Research use
For research use only.
Structure and Identity
Pentamethylbenzoic acid (2,3,4,5,6-pentamethylbenzoic acid) is a highly substituted aromatic carboxylic acid featuring a benzene ring bearing five methyl groups and one carboxyl (–CO2H) function, imparting pronounced steric bulk and electron donation to the aryl core.
Item-specific identifiers (from Product Data)
SKU: P1072589
CAS: 2243-32-5
PubChem CID: 75236
InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
SMILES: Not specified for this item; refer to CoA/Spec Sheet.
Literature/computed structural data (for reference; not item specifications)
Example SMILES (literature): O=C(O)c1c(C)c(C)c(C)c(C)c1C
Structural features: one benzoic acid function para to no substituents (ring fully substituted by Me at 2,3,4,5,6); five ring methyls create a shielded carboxyl-bearing ring carbon and increased lipophilicity; no stereocenters; planar aromatic core with bulky peripheral Me groups.
2D structural description in words (general): a benzoic acid core whose ring hydrogens are replaced at all non-carboxyl positions by methyl groups; the –CO2H is conjugated with the aromatic ring, while methyl groups are hyperconjugative, donating electron density and increasing steric hindrance around the ring.
Synthetic Utility
Pentamethylbenzoic acid is a sterically and electronically distinctive aryl acid that enables preparation of hindered benzoyl derivatives and serves as an entry point to decarboxylative aryl functionalization.
Functional group handles and reactivity (general/literature)
Carboxylic acid: convertible to acyl chlorides (SOCl2/(COCl)2 + cat. DMF), mixed anhydrides (iBuOCOCl), imidazolides (CDI), activated esters (NHS/NHPI), esters (Fischer or Mitsunobu-type), and amides (carbodiimide or coupling-agent mediated).
Aromatic ring: fully methylated (no electrophilic substitution sites remaining), minimizing undesired EAS; strong electron donation makes the aryl acyl derivatives less electrophilic and increases steric hindrance in acylations, useful for selectivity.
Named/representative transformations
Friedel–Crafts acylation using the derived acid chloride to install the pentamethylbenzoyl group onto arenes/heteroarenes (AlCl3 or milder catalysts; note steric effects).
Steglich esterification (DCC/DMAP) for hindered alcohols; DMAP accelerates acyl transfer from a bulky acyl donor.
Curtius or Schmidt from the acyl azide (via acyl chloride + NaN3) to access isocyanates/urethanes (handle azides with extreme caution; specialized safety required).
Decarboxylative cross-coupling via redox-active esters (NHPI/DHPI) under photoredox/Ni catalysis to forge C–C/C–N/C–S bonds.
Retrosynthetic value
The acid can be assembled from pentamethylbenzene via directed oxidation/carboxylation approaches; conversely, it is a convergent branch point to a family of pentamethylbenzoyl esters, amides, and ketones for SAR studies or materials motifs.
Target Specificity
Not applicable. This product is a small-molecule aromatic carboxylic acid, not a biological targeting reagent (e.g., antibody, ligand with defined biological target specificity). No antigen/epitope, clone, isotype, or species reactivity information applies.
Domande frequenti
How should this product be stored?
Store at room temperature.
What is the purity of this product?
This product is supplied at ≥95% purity (chemical assay). Lot-specific values are stated on the Certificate of Analysis.
What are the CAS number, molecular formula and molecular weight?
The CAS Number is 2243-32-5. InChIKey MNLKGWIYXCKWBU-UHFFFAOYSA-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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