4-Mercapto-2-methylphenol - ≥98% , CAS No.32281-01-9

CAS: 32281-01-9 Cat. No.: M1072870 Formula: C₇H₈OS Peso molecolare: 140.2 PubChem CID: 11320974

GRADE & PURITY ≥98%

Storage

Room temperature

Specifications

Specifiche e purezza

≥98%

Condizioni di conservazione di stoccaggio

Room temperature

Purezza

≥98%

Nomi e identificatori

• Sorrisi canonici: CC1=C(C=CC(=C1)S)O
• IUPAC Name: 2-methyl-4-sulfanylphenol
• InChIKey: UMJGOCMSBZWCNY-UHFFFAOYSA-N
• INCHI: 1S/C7H8OS/c1-5-4-6(9)2-3-7(5)8/h2-4,8-9H,1H3
• Isomeri SMILES: CC1=C(C=CC(=C1)S)O
• PubChem CID: 11320974
• Peso molecolare: 140.2

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Benzenoids
    • Classe Thiophenols

• Kingdom: Organic compounds
• Superclass: Benzenoids
• Classe: Thiophenols
• Subclass: Not available
• Intermediate Tree Nodes: Not available
• Direct Parent: Thiophenols
• Alternative Parents: Thiohydroquinones Ortho cresols Toluenes 1-hydroxy-2-unsubstituted benzenoids Thiols Organooxygen compounds Hydrocarbon derivatives
• Molecular Framework: Aromatic homomonocyclic compounds
• Substituents: Thiophenol - Thiohydroquinone - O-cresol - 1-hydroxy-2-unsubstituted benzenoid - Toluene - Phenol - Monocyclic benzene moiety - Arylthiol - Organic oxygen compound - Hydrocarbon derivative - Organosulfur compound - Organooxygen compound - Aromatic homomonocyclic compound
• Descrizione: This compound belongs to the class of organic compounds known as thiophenols. These are compounds containing a thiophenol ring, which a phenol derivative obtained by replacing the oxygen atom from the hydroxyl group (attached to the benzene) by a sulfur atom.
• External Descriptors: Not available

Data sources

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.

DOI: 10.1186/s13321-016-0174-y

Proprietà chimiche e fisiche

• Peso molecolare: 140.200 g/mol
• XLogP3: 1.500
• Hydrogen Bond Donor Count: 2
• Hydrogen Bond Acceptor Count: 2
• Rotatable Bond Count: 0
• Exact Mass: 140.03 Da
• Monoisotopic Mass: 140.03 Da
• Topological Polar Surface Area: 21.200 Ų
• Heavy Atom Count: 9
• Formal Charge: 0
• Complexity: 94.900
• 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

Application Protocols

Not applicable for immunoassays or cellular staining workflows. No validated protocols (WB, IHC, IF, FC, ELISA) are associated with this small-molecule reagent. For synthetic or materials applications, refer to the Reaction Conditions and Synthetic Utility sections.

Biological Roles

This product is a small aromatic thiol/phenol intended for research and synthetic use; it is not a biological macromolecule or buffer component.

• General biochemical considerations (literature)
  • Phenolic groups participate in hydrogen bonding and can act as antioxidants/redox mediators; thiols are redox-active and can form disulfides.
  • Aromatic thiols can interact with soft metal centers (e.g., Au, Ag, Cu) and are used to model metal–thiolate interactions in proteins and surfaces.
  • Dual –OH/–SH functionality provides a platform to study chemoselective modification and redox switching in small-molecule systems.

No medical or therapeutic roles are implied; for research use only.

Buffer Applications

Not typically used as a biological buffer. As an aromatic thiol/phenol, it does not form classical buffering systems in physiological pH ranges with well-defined pKa spacing. For experimental work requiring pH control, select established buffers (e.g., phosphate, HEPES, MOPS) and use this compound only as a functional additive or substrate when appropriate.

Green Alternatives

• Solvent and reagent choices
  • Replace chlorinated solvents (DCM, chloroform) with ethyl acetate or 2-MeTHF where feasible.
  • For base-mediated S-alkylations, consider acetone, MeCN, or 2-MeTHF instead of DMF/DMSO when substrate solubility allows.
  • For C–S cross-coupling, use bio-derived 2-MeTHF or CPME and milder inorganic bases (K3PO4) to reduce waste and improve workup (literature experience).
• Oxidation and redox steps
  • Prefer catalytic aerobic oxidations (O2/air with TEMPO or metal catalysts) over stoichiometric halogen oxidants for disulfide formation, when selectivity can be maintained.
• Workup/waste minimization
  • Apply solvent recycling, microscale chromatography, or crystallization-induced phase separation (CIPS) to minimize silica waste.
• Comparative overview (general, not item-specific)
  • Conventional: DMF/DMSO, DCM, toluene; stoichiometric halogen oxidants; Pd with high ligand loading.
  • Greener alternative: 2-MeTHF/CPME/EtOAc; aqueous micellar media for S-alkylations where compatible; catalytic aerobic oxidation; lower Pd loadings or Cu-catalysis.
• Trade-offs
  • Greener solvents may alter chemoselectivity between O- and S-alkylation; pilot screens are recommended.
  • Aqueous systems can accelerate thiol oxidation; include antioxidants or inert atmosphere if thiol integrity is important.

Pharmaceutical Uses

No pharmacopeial excipient status or formulation role is specified for this item; refer to CoA/Spec Sheet. In general laboratory research, phenolic thiols may be explored as reactive intermediates or monomers for conjugation chemistry or redox-responsive materials. This product is supplied strictly for research use only, not for human or veterinary use, and no therapeutic claims are made.

Physical Properties

• Item-specific specifications
  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.
  • Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular formula (item): Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular weight (item): Not specified for this item; refer to CoA/Spec Sheet.
• Literature/estimated properties (reference values; not product specifications)
  • Molecular formula (literature): C7H8OS
  • Formula weight (literature): ~140.20 g/mol
  • Expected physical state: low-melting solid or viscous liquid with characteristic thiol odor (literature, class behavior of aryl thiols/phenols)
  • Acid–base characteristics: phenolic pKa typically ~9–10; aryl thiol pKa typically ~6–7 (literature ranges; exact values depend on substitution and solvent)
  • Boiling point: aryl thiol/phenol derivatives of this size often show BP in the ~230–280 °C range with possible decomposition (literature trend; exact value not established for this isomer)
  • Melting point: not well-established in open literature for this specific isomer; may be low-melting or oil at ambient temperature (literature trend)
  • Density: expected ~1.0–1.2 g/mL at 20–25 °C (literature trend for aryl thiols/phenols)
  • Solubility: sparingly soluble in water; miscible with many organic solvents (EtOAc, alcohols, chlorinated solvents, aromatics). Phenoxide/thiolate salts are water-soluble (literature, qualitative).
  • LogP: moderate hydrophobicity anticipated for mono-aryl thiol/phenol (~2–3, literature class trend).
  • Refractive index: aryl thiol/phenol oils often nD20 ~1.55–1.60 (literature trend).

Quality and Grades

• Item-specific quality information
  • Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.
  • Stabilizers/Inhibitors: Not specified for this item; refer to CoA/Spec Sheet.
• How to interpret common grades (general guidance)
  • Analytical/Reagent grade: suitable for most synthetic applications; typical impurity limits for metals, acidity, and color.
  • High-purity or GC/HPLC grade (if applicable): tighter control of UV-absorbing impurities and residual solvents; beneficial for trace/analytical work or photochemical studies.
• Considerations specific to phenolic thiols (general)
  • Oxidation control: Trace oxygen and metals catalyze thiol oxidation to disulfides. BHT or small amounts of reducing agents (e.g., ascorbate, phosphines) are sometimes used in research workflows; verify compatibility and presence/absence on CoA.
  • Water content: Moisture promotes hydrolysis/oxidation and shifts acid–base equilibria; Karl Fischer moisture is often monitored for sensitive applications. This item’s water specification is not provided here.
  • Chromophoric impurities: Aromatic sulfur species can have strong UV absorbance; for chromatographic use, seek low-UV grades if available.
• Documentation
  • Always consult the lot-specific CoA and Spec Sheet for assay, GC purity profile, residual solvents, and any stabilizer or inhibitor present. These documents supersede generalized descriptions.

Reaction and Applications

• Nucleophilic substitutions and alkylations
  • The aryl thiol is a soft nucleophile; S-alkylation with primary alkyl halides or sulfonates affords thioethers under mild base (K2CO3, Cs2CO3) in polar aprotic solvents (acetone, MeCN, DMF). Competing O-alkylation of the phenol is possible; base choice and temperature control chemoselectivity (literature best practices).
• Disulfide chemistry
  • Controlled aerobic or reagent-promoted oxidation (I2, H2O2, DMSO, or metal-catalyzed) generates the corresponding disulfide dimer. Disulfide/thiol redox interconversion is useful for linker design and redox-responsive materials (literature).
• Aryl C–S bond formation (cross-coupling)
  • Palladium- or copper-catalyzed coupling of aryl/heteroaryl halides or triflates proceeds efficiently to diaryl sulfides. Ligand sets such as XPhos/BrettPhos (Pd) or CuI with diamine ligands are common; bases include K3PO4, Cs2CO3; solvents: toluene, dioxane, DMF (literature).
• Electrophilic aromatic substitution
  • The –OH and –SH groups activate the ring, enabling further substitution at remaining positions (3,5,6). Nitration, sulfonylation, or Friedel–Crafts acylation can be directed, though protection of –OH/–SH may be required to avoid side reactions (literature strategy).
• Protection strategies
  • –OH can be protected as silyl ethers or benzyl ethers; –SH as thioacetates (AcS–) or S-benzyl groups. Differential protection enables selective downstream functionalization (literature).
• Applications context (general)
  • Useful as a bifunctional monomer/intermediate for ligands, redox-active materials, polymer/oligomer modification, and as a handle for surface immobilization via Au–S interactions while retaining a phenolic site for further derivatization (literature examples).

Reaction Conditions

General literature guidance for closely related aryl thiol/phenol systems (optimize per substrate and scale):

• S-alkylation (thioether formation)
  • Reagents: alkyl bromide/iodide or tosylate (1.1–1.5 eq), K2CO3 or Cs2CO3 (1.5–2.5 eq).
  • Solvent: acetone, MeCN, or DMF; 0.1–0.5 M.
  • Temperature/time: 20–60 °C, 2–12 h.
  • Notes: favor S- over O-alkylation by using milder base and controlling temperature; monitor by TLC/GC.
• O-alkylation (aryl ether formation)
  • Reagents: alkyl halide (1.2 eq), NaH (1.1 eq) or K2CO3 (2 eq).
  • Solvent: THF or DMF; 0–25 °C (NaH) or 40–70 °C (K2CO3).
  • Notes: protect –SH (e.g., as thioacetate) to avoid competing S-alkylation.
• Disulfide formation
  • Reagents: I2 (0.5 eq) or air/O2 with catalytic base/metal.
  • Solvent: MeOH, EtOH, or DCM; 0–25 °C.
  • Notes: stop at disulfide; excess oxidant leads to sulfinic/sulfonic acids.
• C–S cross-coupling (diaryl sulfide)
  • Catalyst: Pd2(dba)3 (1–2 mol%) + XPhos/BrettPhos (2–4 mol%) or CuI (5–10 mol%) with diamine ligand.
  • Electrophile: aryl bromide/iodide/triflate (1.1 eq); base: K3PO4 or Cs2CO3 (2 eq).
  • Solvent/temp: toluene or dioxane (80–110 °C) or DMF (60–90 °C); 2–16 h.
  • Notes: exclude air/moisture to limit thiol oxidation and catalyst poisoning.
• Workup tips
  • Quench bases carefully; remove residual sulfur species by percolation over activated carbon or by oxidative wash (Na2S2O3) when compatible.

Safety and Handling

• Item-specific hazard data (from Product Data)
  • GHS Classification: Not specified for this item; refer to SDS.
  • 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.
• General safety profile (literature/analog-based; defer to SDS for authoritative guidance)
  • Phenols are corrosive/irritant; aryl thiols are typically harmful by inhalation/ingestion/skin contact and cause severe eye/skin irritation. Strong, persistent odor typical of thiols.
  • May form oxidized products (disulfides, sulfonic/sulfinic acids) upon exposure to air/oxidants. Avoid strong oxidizing agents, acyl halides/anhydrides (exothermic acylation), and bases/acids without proper control.
• Handling recommendations
  • Use in a certified fume hood due to thiol odor and potential volatility of vapors/aerosols.
  • PPE: lab coat, nitrile gloves (change regularly), splash goggles; consider double-gloving for extended operations.
  • Avoid skin contact; phenolic materials can penetrate skin. Use spatulas/syringes; keep containers tightly closed.
• First-aid overview (consult SDS for details)
  • Inhalation: move to fresh air; seek medical advice if symptoms persist.
  • Skin contact: remove contaminated clothing; wash with soap and water for ≥15 min.
  • Eye contact: rinse cautiously with water for ≥15 min; remove contacts if easy; seek medical attention.
  • Ingestion: rinse mouth; do not induce vomiting; seek medical attention.
• Fire and reactivity
  • Combustible; use CO2, dry chemical, or foam. Thermal decomposition may release sulfur oxides and phenolic vapors.
  • Store away from peroxides/oxidants and metal salts that catalyze oxidation.

Solvent Selection

• Polarity and miscibility (general behavior)
  • 4-Mercapto-2-methylphenol is moderately nonpolar but contains both –OH and –SH. It is typically soluble in alcohols, acetone, ethyl acetate, DCM, toluene, and other organic solvents; low solubility in water unless deprotonated.
  • Deprotonation (to phenoxide/thiolate) dramatically increases solubility in polar protic/aprotic media and in water.
• Choosing solvents by task
  • Nucleophilic substitutions/S-alkylations: polar aprotic solvents (DMF, DMSO, MeCN) enhance thiolate nucleophilicity; ensure anhydrous conditions.
  • O- vs S-selective alkylation: softer, less basic conditions (e.g., K2CO3 in acetone/MeCN) favor S-alkylation; strong bases (NaH) in THF/DMF can lead to mixed O/S alkylation—optimize carefully (literature guidance).
  • Oxidations to disulfides: alcohols or MeOH/DCM mixtures are common; control oxygen and catalyst loadings.
  • Cross-couplings (C–S bond formation): toluene, dioxane, CPME, or DMF with Pd/Cu catalysts are frequently used.
• Small comparison (general)
  • Alcohols: good solubility and ease of workup; may engage in H-bonding and proton transfer.
  • Chlorinated solvents (DCM): excellent solubility; consider environmental and safety impact.
  • Ethers (THF, 2-MeTHF): good for base-mediated reactions; watch peroxide formation in ethers (general ether caution).
  • Green options: 2-MeTHF or CPME can replace THF/toluene in many transformations; Me-THF often improves phase separation and reduces peroxide risk compared to THF (literature).

Storage and Reconstitution

• Item-specific storage
  • Storage Conditions: Room temperature (per Product Data).
  • Shipped In: Not specified for this item; refer to CoA/Spec Sheet.
• Practical storage guidance (general for aryl thiols/phenols)
  • Store tightly sealed in amber glass to minimize light exposure and air ingress; consider an inert gas blanket (N2/Ar), especially after opening, to limit oxidation to disulfides.
  • Keep dry; use desiccant. Avoid proximity to oxidizers and bases/acyl chlorides.
  • If solidifies or shows crystallization, gently warm to ambient and homogenize before use; verify purity by GC/HPLC/NMR.
• Reconstitution/dispensing
  • If supplied as a solid or viscous oil, dissolve in dry, oxygen-free solvent (e.g., anhydrous EtOAc, THF, MeCN) just prior to use.
  • For stock solutions, prepare under inert atmosphere, store in sealed amber vials at room temperature as permitted by stability; check for discoloration or odor changes indicating oxidation.
• Shelf-life
  • Monitor by TLC/GC for formation of disulfide or higher oxidation products over time. Always refer to the lot-specific CoA/SDS for definitive storage and handling instructions.
• Research use note
  • For research use only.

Structure and Identity

A bifunctional aromatic building block bearing both a phenolic hydroxyl and an aryl thiol (mercapto) group on a 2-methyl-substituted benzene ring.

• Item-specific identifiers (from Product Data)
  • CAS: 32281-01-9
  • CID (PubChem): 11320974
  • InChIKey: 363630 (as provided; verify against SDS/CoA for authoritative identifier)
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
• Literature structural information (for reference only; not item specifications)
  • Common name: 4-mercapto-2-methylphenol (syn. 2-methyl-4-mercaptophenol; 4-sulfanyl-2-methylphenol)
  • Typical molecular formula: C7H8OS (literature)
  • Typical molecular weight: ~140.20 g/mol (literature)
  • Possible SMILES representation: CC1=CC(=CC=C1O)S (literature)
• Structural features (general description)
  • Aromatic ring bearing three substituents: phenolic –OH at C1, methyl at C2 (ortho to –OH), and thiol –SH at C4 (para to –OH).
  • Functional groups: phenol (acidic, hydrogen-bond donor/acceptor), aryl thiol (soft nucleophile, readily oxidized to disulfide), and a weakly electron-donating methyl group.
  • Directing effects: –OH and –SH are activating, ortho/para directors for electrophilic aromatic substitution; existing substitution pattern leaves positions 3,5,6 accessible.
  • 2D description in words: a benzene ring with OH at the top (position 1), a CH3 adjacent clockwise (position 2), and an SH group opposite the OH (position 4).

Synthetic Utility

• Bifunctional handle
  • The co-presence of –OH and –SH enables orthogonal transformations: selective protection/alkylation/acylation at sulfur versus oxygen to build complexity from a single aromatic core (literature strategies).
• S-centered transformations
  • S-alkylation (thioether formation), S-acylation (thioesters), oxidative coupling to disulfides, and metal-catalyzed aryl C–S cross-coupling are high-yielding routes to sulfide architectures.
• O-centered transformations
  • O-alkylation to aryl ethers, O-acylation to esters/carbonates, or conversion to activated phenol derivatives (e.g., triflates) enabling further cross-couplings.
• Ring functionalization
  • Remaining positions (3,5,6) can be diversified via electrophilic substitution or directed metalation after suitable protecting groups are installed.
• Retrosynthetic value
  • Serves as a convergent node: sulfur chemistry introduces linkers or metal-binding motifs; oxygen chemistry introduces solubilizing or photophysical groups; methyl holds electronic/steric bias that can tune reactivity.
• Surface and materials applications (research)
  • The aryl thiol can anchor to gold surfaces (Au–S) while the phenolic site participates in polymerization or further coupling, enabling monolayer or hybrid material construction (literature).

Target Specificity

Not applicable. This product is a small organic molecule, not an antibody, enzyme, or probe with biological target specificity. No antigen/epitope, clone, isotype, or species reactivity information applies.