Ethyl 4-sulfanylbenzoate - ≥95% , CAS No.28276-32-6

CAS: 28276-32-6 Cat. No.: E1016472 Formula: C₉H₁₀O₂S Molecular Weight: 182.240 EC Number: 829-943-3

GRADE & PURITY ≥95%

Storage

Room temperature

Specifications

Specifications & Purity

≥95%

Storage

Room temperature

Purity

≥95%

Names and Identifiers

• Canonical Smiles: CCOC(=O)C1=CC=C(C=C1)S
• IUPAC Name: ethyl 4-sulfanylbenzoate
• InChIKey: NBBWLOJCZSYDAD-UHFFFAOYSA-N
• INCHI: 1S/C9H10O2S/c1-2-11-9(10)7-3-5-8(12)6-4-7/h3-6,12H,2H2,1H3
• Molecular Weight: 182.240

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Benzenoids
    • Class Benzene and substituted derivatives
      • Subclass Benzoic acids and derivatives
        • Level5 Sulfanylbenzoic acids and derivatives
          • Level6 P-sulfanylbenzoic acids and derivatives

• Kingdom: Organic compounds
• Superclass: Benzenoids
• Class: Benzene and substituted derivatives
• Subclass: Benzoic acids and derivatives
• Intermediate Tree Nodes: Sulfanylbenzoic acids and derivatives
• Direct Parent: P-sulfanylbenzoic acids and derivatives
• Alternative Parents: Benzoic acid esters Thiophenols Benzoyl derivatives Carboxylic acid esters Monocarboxylic acids and derivatives Thiols Organooxygen compounds Organic oxides Hydrocarbon derivatives
• Molecular Framework: Aromatic homomonocyclic compounds
• Substituents: P-sulfanylbenzoic acid or derivatives - Benzoate ester - Thiophenol - Benzoyl - Carboxylic acid ester - Arylthiol - Monocarboxylic acid or derivatives - Carboxylic acid derivative - Organic oxygen compound - Organic oxide - Hydrocarbon derivative - Organosulfur compound - Organooxygen compound - Aromatic homomonocyclic compound
• Description: This compound belongs to the class of organic compounds known as p-sulfanylbenzoic acids and derivatives. These are benzoic acids (or derivatives) which bear a sulfanyl group (R-SH) attached to the benzene ring at positions 1 and 4, respectively.
• 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

Chemical and Physical Properties

• Molecular Weight: 182.240 g/mol
• XLogP3: 3.000
• Hydrogen Bond Donor Count: 1
• Hydrogen Bond Acceptor Count: 3
• Rotatable Bond Count: 3
• Exact Mass: 182.04 Da
• Monoisotopic Mass: 182.04 Da
• Topological Polar Surface Area: 27.300 Ų
• Heavy Atom Count: 12
• Formal Charge: 0
• Complexity: 151.000
• 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

Application Protocols

No application protocols are provided for this item. As a small-molecule reagent, usage conditions depend on the specific synthetic transformation. Refer to the Reaction & Applications and Reaction Conditions sections for general guidance, and validate conditions at small scale before process optimization.

Biological Roles

No item-specific biological testing data are provided for this product. The following notes are general insights about aromatic thiols and benzoate motifs from the literature and are not claims about this item.

• Redox chemistry: Aryl thiols (Ar–SH) can participate in reversible redox processes (thiol/disulfide exchange) and can reduce mild oxidants; their acidity and nucleophilicity enable interactions with soft metal centers.
• Metal coordination: Thiolate anions bind to soft metals (e.g., Au, Ag, Cu, Zn) and are widely used in self-assembled monolayers and metalloprotein model studies.
• Benzoate ester role: The ethyl benzoate group modulates lipophilicity and electronic properties of the aromatic ring; it is hydrolytically cleavable to yield the corresponding benzoic acid derivative under enzymatic or chemical conditions (general chemistry context).

This product is offered for research use only and is not intended for any form of in vivo use. No pharmacological, toxicological, or clinical properties are implied.

Buffer Applications

Not typically used as a buffering reagent. As a hydrophobic aromatic thiol ester, this compound does not form classical conjugate acid/base buffer systems in aqueous media. If aqueous work is required (e.g., biphasic reactions or extractions), select buffer systems compatible with thiols (e.g., pH 7–8 phosphate or borate) and minimize oxygen to suppress oxidation to disulfides. For protein-related buffers, be aware that free thiols can undergo disulfide exchange; avoid unless intentionally reducing/functionalizing thiols.

Green Alternatives

As a building block, the greener choices relate to solvent selection, protection strategies, and oxidation control rather than a direct substitute compound.

• Greener handling strategies

  • Use greener solvents where feasible: EtOAc, 2-MeTHF, cyclopentyl methyl ether (CPME), or alcoholic media instead of chlorinated solvents (DCM, chloroform) when reaction compatibility allows.
  • In situ thiol generation: Employ thioacetate or thioester precursors that are deprotected under mild basic conditions at point-of-use to minimize thiol emissions/odor and oxidative waste.
  • Oxidation minimization: Conduct reactions under air-free conditions to reduce byproduct disulfide formation and downstream purification burden.

• Comparison (general, literature)

  Option | Advantages | Trade-offs --- | --- | --- Free aryl thiol (this item) | Direct, high reactivity; no deprotection step | Odor, oxidation to disulfide, handling precautions Aryl thioacetate precursor | Odor-mitigated, bench-stable; releases thiol in situ | Requires base for deprotection; acetate waste Solvent: EtOAc/2-MeTHF | Better EHS profile than DCM; renewable options | Different polarity/evaporation; may alter kinetics

Selection should be guided by process safety, waste minimization, and performance, validated at the lab scale before scale-up.

Pharmaceutical Uses

No pharmacopeial grade or excipient status is specified for this item. In general, aromatic thiols are not common excipients due to odor and reactivity. If used in pharmaceutical research contexts, their roles are typically limited to synthetic intermediates or surface modifiers in device R&D.

• Item-specific status: Grade, residual solvent limits, and compliance with pharmacopeial monographs are Not specified for this item; refer to CoA/Spec Sheet.
• Formulation caution: Free thiols may be incompatible with peroxide-bearing excipients and oxidizing environments; they can also interact with metal-containing components.

This product is for research use only and not for human or veterinary use.

Physical Properties

• Item-specific properties (from Product Data)

  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Formula: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular Weight: Not specified for this item; refer to CoA/Spec Sheet.

• Literature/general reference values (non-spec, for context)

  • Empirical formula (literature): C9H10O2S
  • Approx. formula weight (literature): ~182.24 g/mol
  • Acid–base: Aromatic thiol (Ar–SH) is a weak acid; pKa for para-substituted aryl thiols commonly lies in the ~6–8 range (literature, substituent-dependent). The electron-withdrawing ester para to –SH can modestly lower the thiol pKa relative to unsubstituted thiophenol.
  • Polarity/solubility: Expected to be sparingly soluble in water and soluble in common organic solvents (e.g., DCM, chloroform, ethyl acetate, THF, alcohols) — literature generalization for aryl thiol esters.
  • Volatility: Lower volatility than simple thiols of similar MW due to aromaticity and ester functionality (literature trend).

• Not specified for this item (consult CoA/SDS or spec sheet): melting point, boiling point, density, refractive index, logP/logD, UV cutoff, elemental/trace-metal limits, water or peroxide content.

Quality & Grades

• Grade/Purity (item-specific): Not specified for this item; refer to CoA/Spec Sheet.
• Stabilizers/Inhibitors (item-specific): Not specified for this item; refer to CoA/Spec Sheet.

Interpretation and guidance

• In absence of a declared grade, users should verify assay, identity (NMR/GC/LC–MS), and impurity profile via the CoA.
• For chromatography or photochemical work, low UV-absorbing and low-peroxide grades are often desirable; if required, specify HPLC-grade or low-UV impurity criteria when ordering (general guidance).
• Thiol-containing materials can slowly oxidize; materials may be supplied under inert gas or with minimal headspace. If oxidation sensitivity is critical, request recent lot CoA including peroxide/disulfide content (if available) or analyze in-house (e.g., iodometric titration, HPLC).
• Water content, residual metals, and specific contaminants are Not specified for this item; refer to CoA/Spec Sheet.

Reaction & Applications

Ethyl 4-sulfanylbenzoate is a versatile para-thiolated aromatic ester useful as a thiol source, a handle for further functionalization, and a donor/acceptor partner in transformations involving Ar–S chemistry.

Key application families (literature/general)

• Thiolate chemistry: Base-mediated deprotonation (e.g., NaH, K2CO3, DBU) generates the corresponding thiolate for S-alkylation (thioethers), S-acylation (thioesters), and Michael additions to activated alkenes.
• Oxidation states: Controlled oxidation affords the disulfide dimer (ArS–SAr); further oxidation can yield sulfenyl chlorides (via electrophilic halogenation), sulfoxides, or sulfones under stronger conditions.
• Cross-coupling and C–S activation: The Ar–S bond can participate in metal-catalyzed couplings or serve as a leaving group in desulfurative cross-couplings (Ni/Pd-catalysis, literature-dependent).
• Protective and affinity roles: The thiol can anchor to soft metals (Au, Ag, Cu) enabling surface functionalization or SAM formation on gold; the ester modulates solubility and electronic properties.
• Orthogonal reactivity: The ester (–CO2Et) can undergo hydrolysis to p-mercaptobenzoic acid or transesterification to other alkyl benzoates while preserving the aryl thiol under mild conditions.

Practical tips

• Minimize oxygen exposure during thiol handling to suppress disulfide formation; purge vessels and use degassed solvents.
• If odor control is critical, generate the free thiol in situ from a protected precursor (e.g., thioacetate) and immediately consume it.
• Monitor reactions by LC/GC with sulfur-selective detection or UV at ~254–280 nm (literature practice for aryl systems).

Reaction Conditions

General, literature-style guidance for common transformations of para-aryl thiols and benzoate esters. Optimize for your system; these are not product specifications.

• Thiolate formation and S-alkylation
  • Base: K2CO3, Cs2CO3, or NaH (0.5–1.2 equiv) in DMF, DMSO, MeCN, or acetone.
  • Electrophiles: Primary alkyl halides, benzyl halides, activated sulfonates.
  • Temperature: 0–60 °C; typical times 0.5–6 h; monitor by TLC/LC–MS.
• Disulfide formation (dimerization)
  • Conditions: Stir in air/O2 in MeOH or MeCN; or I2 (0.5 equiv) in DCM at 0–25 °C.
  • Workup: Sodium thiosulfate to quench iodine; silica plug to remove colored residues.
• Ester hydrolysis to p-mercaptobenzoic acid
  • Basic: Aqueous NaOH or K2CO3 in MeOH/THF–H2O (0–25 °C), then acidify.
  • Acidic: HCl or H2SO4 in MeOH under reflux for transesterification followed by hydrolysis as needed.
• Oxidation to sulfoxide/sulfone (on Ar–S–R products)
  • Oxidants: mCPBA (0.9–1.1 equiv for sulfoxide; 2.0–2.5 equiv for sulfone) in DCM at 0–25 °C.

Typical isolated yields for well-optimized S-alkylations and hydrolyses are often 70–95% (literature range), subject to substrate and workup. Protect from air/moisture where thiol oxidation or ester hydrolysis is a concern.

Safety & Handling

• Item-specific hazard data (from Product Data)

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

• General safety guidance for aryl thiol benzoate esters (literature/industry practice)

  • Hazards: Aromatic thiols can be skin/eye irritants and may cause respiratory irritation. Many thiols emit strong odors; avoid inhalation and prevent release in poorly ventilated spaces.
  • Oxidation: Thiols can oxidize to disulfides upon air exposure; minimize contact with air/oxidants. Use inhibitors or store under inert gas when feasible.
  • Incompatibilities: Strong oxidizers (risk of exothermic oxidation), strong bases (thiolate formation), and strong acids (possible hydrolysis of the ester under harsh conditions). Avoid copper and heavy metal salts unless thiolate complexation is intended.
  • PPE: Safety glasses, lab coat, and appropriate chemical-resistant gloves (e.g., nitrile). Work in a fume hood.
  • First aid (overview; defer to SDS): Eye—rinse with water for several minutes. Skin—wash with soap/water and remove contaminated clothing. Inhalation—move to fresh air. Ingestion—notify medical personnel; do not induce vomiting unless directed.

Always consult the product-specific SDS for authoritative hazard classification, spill response, waste disposal, and transport information.

Solvent Selection

This product is an organic building block rather than a solvent; however, solvent choice is critical for its handling and reactions.

• Polarity and solubility profile (literature/general)
  • Expected to dissolve well in moderately polar aprotic solvents (DCM, THF, EtOAc, acetonitrile) and in many nonpolar aromatics (toluene). Limited solubility in water.
  • Alcohols (EtOH, iPrOH) typically dissolve aryl esters and may be used when protic media are acceptable.
• Selection tips by use-case
  • Nucleophilic substitutions/thiolate generation: Dry polar aprotics (DMF, DMSO, MeCN, THF) promote deprotonation and SNAr/S-alkylation.
  • Ester chemistry (transesterification/hydrolysis): Alcoholic solvents or biphasic systems (organic/aqueous base or acid) depending on direction.
  • Oxidation to disulfide: Non-nucleophilic solvents (DCM, MeCN) with controlled oxidants.
  • Metal-catalyzed cross-coupling at the aryl–S bond (if applicable): Polar ether/aromatic solvents (dioxane, toluene) are commonly reported.
• Comparison notes
  • DCM vs EtOAc: DCM offers rapid dissolution and easy removal; EtOAc is a greener alternative with higher polarity and better safety but slower evaporation.
  • THF vs 2-MeTHF: 2-MeTHF provides improved sustainability and water tolerance with similar solvency; consider for reactions tolerant to slight variability in polarity.

Storage & Reconstitution

• Storage (item-specific): Room temperature (per Product Data). Store tightly closed in a dry place.
• Shipping: Not specified for this item; refer to CoA/Spec Sheet.

Best practices (general for thiol-containing aromatics)

• Protect from air/oxidants and prolonged light. If long-term storage is anticipated, consider an inert gas headspace (N2/Ar) to limit disulfide formation.
• Avoid prolonged exposure to strong bases/acids to prevent unwanted ester hydrolysis or thiol oxidation.
• If solid: Break up any agglomerates under inert atmosphere; for weighing, minimize open time to reduce odor and oxidation.
• If liquid or viscous: Use septum-capped bottles for syringe transfer under nitrogen when feasible.

Reconstitution/dissolution

• Readily dissolves in common organic solvents (e.g., DCM, EtOAc, THF, MeCN, alcohols) — select anhydrous grades when base-sensitive chemistry is planned.
• For analytical solutions, prepare fresh and store cold/in the dark if oxidation is problematic; add a trace of base or antioxidant only if compatible with downstream use.

Research Use Only: Not for human or veterinary use.

Structure & Identity

Ethyl 4-sulfanylbenzoate (often referred to in the literature as ethyl 4-mercaptobenzoate) is an aromatic thio-functionalized benzoate ester. The molecule features a benzene ring bearing two para-substituents: an ethyl benzoate ester and a thiol (–SH).

• Item-specific identifiers (from Product Data)
  • CAS: 28276-32-6
  • CID: 10845149
  • InChIKey: 233828 (as provided; appears truncated — consult CoA/SDS for the full key)
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
• Literature/computed identifiers and composition (non-spec, informational)
  • Common name (literature): Ethyl 4-mercaptobenzoate; p-mercaptobenzoic acid ethyl ester
  • Empirical formula (literature): C9H10O2S
  • Formula weight (literature): ~182.24 g/mol
• Structural features
  • Aromatic system: Monosubstituted benzene bearing two para-oriented substituents
  • Functional groups: Benzoate ester (–CO2Et) and aromatic thiol (Ar–SH)
  • Connectivity (2D description): The benzene ring bears an ethyl ester of the carboxyl at C1 and an –SH group at C4 (para) relative to the ester carbonyl-bearing carbon.
  • Stereochemistry: None (achiral).

Notes

• The above formula and mass are literature values for the named structure and are provided for general reference; they are not item-specific specifications.

Synthetic Utility

Functional handles present in Ethyl 4-sulfanylbenzoate enable orthogonal transformations useful in multistep synthesis.

• Thiol (Ar–SH)

  • Deprotonation to thiolate for S-alkylation (forming aryl thioethers), S-acylation (thioesters), and conjugate additions.
  • Oxidation manifold: Disulfide formation (mild oxidants, air/O2, I2), sulfenyl halide generation (N-halosuccinimides), and further oxidation to sulfoxides/sulfones (mCPBA, Oxone) when desired.
  • Metal affinity enables immobilization on Au/Ag surfaces for material interfaces.

• Benzoate ester (–CO2Et)

  • Hydrolysis to the corresponding para-mercaptobenzoic acid; useful for coupling (amide formation via EDC/HOBt, HATU) while retaining the aryl thiol.
  • Transesterification to tune solubility and volatility.

• Retrosynthetic value

  • Serves as a para-thiolated aromatic synthon. Downstream cross-coupling from activated derivatives (e.g., via thioether to aryl halide interconversion or metal-catalyzed C–S activation) expands access to para-functionalized benzoates.

• Selectivity considerations

  • Under basic conditions, the thiol is more nucleophilic/acidable than the ester oxygen; choose chemoselective conditions to avoid ester cleavage (e.g., avoid strong aqueous base at elevated temperature unless hydrolysis is desired).

Target Specificity

Not applicable. This product is a small-molecule building block and is not an antibody, enzyme, or affinity reagent. No target, epitope, clone, or isotype information applies.