Methallyl mercaptan , CAS No.5954-68-7

CAS: 5954-68-7 Cat. No.: M1020324 Summenformel: C₄H₈S Molekulargewicht: 88.17 PubChem CID: 11051576

Storage

Room temperature

Specifications

Storage

Room temperature

Namen und Kennungen

• Kanonisches Lächeln: CC(=C)CS
• IUPAC Name: 2-methylprop-2-ene-1-thiol
• InChIKey: UFJYVTQALAAQEQ-UHFFFAOYSA-N
• INCHI: 1S/C4H8S/c1-4(2)3-5/h5H,1,3H2,2H3
• Isomere SMILES: CC(=C)CS
• PubChem CID: 11051576
• Molekulargewicht: 88.17

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Organosulfur compounds
    • Klasse Thiols
      • Subclass Alkylthiols

• Kingdom: Organic compounds
• Superclass: Organosulfur compounds
• Klasse: Thiols
• Subclass: Alkylthiols
• Intermediate Tree Nodes: Not available
• Direct Parent: Alkylthiols
• Alternative Parents: Hydrocarbon derivatives
• Molecular Framework: Aliphatic acyclic compounds
• Substituents: Alkylthiol - Hydrocarbon derivative - Aliphatic acyclic compound
• Beschreibung: This compound belongs to the class of organic compounds known as alkylthiols. These are organic compounds containing the thiol functional group linked to an alkyl chain.
• 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

Chemische und physikalische Eigenschaften

• Siedepunkt (°C): 93°C
• Molekulargewicht: 88.170 g/mol
• XLogP3: 1.800
• Hydrogen Bond Donor Count: 1
• Hydrogen Bond Acceptor Count: 1
• Rotatable Bond Count: 1
• Exact Mass: 88.0347 Da
• Monoisotopic Mass: 88.0347 Da
• Topological Polar Surface Area: 1.000 Ų
• Heavy Atom Count: 5
• Formal Charge: 0
• Complexity: 38.900
• 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

No validated bioassay/diagnostic protocols (e.g., WB, IHC, IF, FC) are applicable to this small-molecule reagent.

• Practical laboratory protocols (general guidance)
  • For thiol–ene coupling: charge substrate and methallyl mercaptan (1.0–1.5 equiv), add photoinitiator (1–2 mol%), degas, irradiate under inert gas until completion by GC/LC. Purify by silica gel chromatography with odor control (activated carbon in waste streams).
  • For S‑alkylation: deprotonate with base in dry polar aprotic solvent, add electrophile dropwise at controlled temperature, quench, extract, and purify. Verify product identity by GC–MS/NMR; check for disulfide by-products.

These are illustrative, literature-style workflows; adapt to your substrate and consult detailed references.

Biological Roles

This product is a small synthetic thiol, not a native metabolite. No biological roles are assigned to this specific compound in the Product Data.

• General context for thiols in biology (literature; not item-specific claims)

  • Thiols (–SH) are central to redox biology (e.g., cysteine, glutathione) and enzyme active sites. They participate in disulfide formation, metal binding, and nucleophilic catalysis.
  • Low-molecular-weight aliphatic thiols can occur as volatile aroma compounds in foods and fermentation, but methallyl mercaptan itself is primarily a laboratory reagent/intermediate.
  • Reactivity toward electrophiles and oxidants is high; in biological systems, free thiols are often rapidly scavenged or oxidized.

• Laboratory relevance

  • Can serve as a model nucleophile for probing S‑alkylation selectivity or radical thiol–ene mechanisms in biomimetic studies.

No clinical or therapeutic uses are implied; for research use only.

Buffer Applications

Not typically used as a buffering agent. As a hydrophobic, odorous thiol, it is unsuitable for preparing aqueous buffer systems.

• Practical guidance
  • If reactions involving this reagent must be conducted in aqueous media, employ biphasic systems or water-miscible organic co-solvents (e.g., MeCN, t‑BuOH) with appropriate base to generate the thiolate, and maintain efficient ventilation.
  • For pH control, use established buffers (e.g., phosphate, tris) independent of this reagent.

Green Alternatives

• Environmental/operational concerns (general)

  • Low-MW thiols have intense odors and potential acute toxicity; fugitive emissions can cause odor complaints well below occupational limits. Volatility increases handling losses.

• Greener strategies and substitutes (contextual, literature-based)

  • Use masked thiols (e.g., thioacetates, S‑trityl derivatives) to attenuate odor during multistep synthesis; unmask at the end (hydrolysis or reductive deprotection). Trade-off: additional step and reagents.
  • Polymer-supported thiols or silica-bound thiols for scavenging/grafting applications reduce odor and facilitate separation; may have lower reactivity and higher cost.
  • For thiol–ene chemistry, consider less volatile higher‑boiling thiols if the final structure tolerates homologation. Trade-off: altered product structure and sterics.
  • In radical additions for polymer modification, alternative chain-transfer agents (e.g., dodecyl mercaptan, RAFT agents such as dithiobenzoates/trithiocarbonates) can reduce odor/volatility but change kinetics and end‑group chemistry.
  • Solvent choices: prefer ethyl acetate, 2‑MeTHF, or dimethyl carbonate over chlorinated solvents when compatible with reactivity and workup.

• Process measures

  • Closed transfers, cold traps, and activated-carbon off‑gas filters markedly reduce emissions.
  • Micro-encapsulation or ampouled packaging can further limit exposure at scale.

Selection should balance EHS gains with reactivity, cost, and downstream compatibility.

Pharmaceutical Uses

No pharmacopeial status or excipient role is provided for this item.

• Contextual, non-clinical information (literature/general)
  • Small alkanethiols are occasionally used as synthetic intermediates or transient protecting/anchoring groups in API/process chemistry to introduce thioether functionality or to engage in thiol–ene diversification.
  • Due to strong odor and handling considerations, direct use in formulated drug products is uncommon. Any use would be strictly as an intermediate under GMP with rigorous impurity control.

This product is supplied strictly for research and laboratory use only. No medical or clinical 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.

• Literature/general values (for context; not item-specific specifications)

  • Molecular formula: C4H8S (thiol)
  • Molecular weight: ~88.17 g/mol
  • Physical state: typically a colorless to pale liquid with a strong thiolic odor (literature, general for low-MW thiols)
  • Acid–base: pKa of simple alkanethiols typically ~10–11 (literature); expect similar acidity for a primary alkenyl thiol.
  • Density: small alkanethiols are commonly near 0.85–0.95 g/mL at 20–25 °C (literature trend).
  • Volatility: low boiling, readily volatile; strong odor management required (literature note for C3–C5 thiols).
  • Solubility: miscible with many organic solvents (e.g., ethers, hydrocarbons, chlorinated solvents, alcohols); low to moderate water solubility typical for C4 thiols (literature expectations).
  • Refractive index: small thiols often nD20 ~1.45–1.48 (literature trend).

Notes

• Exact numerical values (bp/mp/density/RI/UV cutoff/trace impurities) are not specified for this item; consult the CoA/Spec Sheet and SDS for definitive parameters.
• As with most low-MW thiols, odor thresholds are extremely low; ensure closed handling systems to minimize fugitive emissions.

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.

• Guidance for interpreting grades (general)

  • Research-grade thiols are typically controlled for identity (GC/GC–MS), assay (% area), and common impurities (disulfide, solvent, moisture). Low UV background is less critical unless the material is used in photochemical or analytical contexts.
  • Where stated, “anhydrous” designations target low water content suitable for air/moisture-sensitive transformations (e.g., metal-catalyzed couplings, strong-base deprotonations). For thiols, moisture primarily impacts base-mediated reactions and oxidation rates.
  • Stabilizer policy: Some suppliers add trace antioxidant or maintain inert-atmosphere packaging to minimize disulfide formation. Presence/absence of stabilizers can influence kinetics in radical thiol–ene chemistry and odor profile.

• Recommended verification on receipt (good practice)

  • Inspect by GC for a single dominant peak; check for the corresponding disulfide (~M.W. ≈ 176) as a potential impurity.
  • Titrate thiol content (iodometric or Ellman’s reagent) when precise –SH stoichiometry matters.
  • For sensitive applications, determine water content (Karl Fischer) and residual solvent profile as required by your protocol.

Always defer to the item’s CoA/Spec Sheet for definitive specifications and release criteria.

Reaction and Applications

• Functional role: primary alkenyl thiol. The –SH group is both a soft nucleophile and a radical hydrogen donor; the allylic scaffold can engage in radical pathways.

• Representative uses (literature/general)

  • Thiol–ene click chemistry: under photochemical (UV/visible, photoinitiator) or radical initiation (AIBN/ACCN), adds across electron-rich/poor alkenes on partner molecules, yielding anti-Markovnikov thioethers with high efficiency.
  • S‑Alkylation and thioether formation: deprotonation (e.g., NaH, K2CO3, DBU) followed by SN2 on primary alkyl halides, mesylates, or epoxides to install the methallylthio group.
  • Conjugate additions to activated alkenes: as a soft nucleophile, adds to Michael acceptors (acrylates, maleimides) under base or thiolate catalysis to give β-thioethers.
  • Oxidation chemistry: controlled oxidation to disulfide dimer; further to sulfoxide/sulfone under stronger oxidants if required synthetically.
  • Polymer and material modification: chain transfer agent or crosslinking in radical polymerizations; surface/ligand modification through thiol–ene grafting.

• Practical tips

  • Exclude oxygen for radical chemistry to avoid inhibition; consider degassing by freeze–pump–thaw or sparging.
  • For base-promoted S-alkylation, generate the thiolate in situ and avoid over-alkylation; monitor by GC.
  • Odor control: conduct weigh-outs and additions in capped vials; quench residues with oxidant (e.g., NaOCl) in a controlled fashion before disposal per institutional guidance.

Refer to reaction-specific literature for exact initiator loadings, wavelengths, and stoichiometries.

Reaction Conditions

The following are literature-style general conditions for common transformations of aliphatic thiols; they are guidance, not specifications for this item.

• Thiol–ene additions

  • Conditions: UV or blue light with photoinitiator (e.g., 1–2 mol% DMPA or Ir(ppy)3), or 5–10 mol% AIBN at 60–80 °C.
  • Solvents: toluene, acetonitrile, ethyl acetate, bulk (neat) if viscosity allows.
  • Atmosphere: nitrogen/argon; oxygen inhibits radicals.
  • Typical times: 0.5–6 h; monitor by GC/LC.

• S‑Alkylation (thioether synthesis)

  • Base: K2CO3, Cs2CO3, or NaH (0.5–1.2 equiv) to form thiolate in DMF/MeCN/THF.
  • Electrophiles: primary halides, mesylates, benzyl derivatives (SN2). Avoid secondary/tertiary (elimination/low yield).
  • Temperature: 0–25 °C (reactive benzyl), up to 60 °C for less reactive substrates.

• Michael additions (to activated alkenes)

  • Catalysis: base (TEA/DBU) or nucleophilic catalysts (thiolate); polar solvents (MeOH, MeCN).
  • Temperature: 0–25 °C typically; rapid reactions.

• Oxidation to disulfide

  • Reagents: I2 (0.5 equiv), air/O2 with catalytic Cu/Fe, or DMSO under controlled conditions.
  • Solvent: MeOH, CH2Cl2, or biphasic with base; monitor to avoid overoxidation.

Yields are substrate-dependent; consult primary literature for your specific system before scale-up.

Safety and Handling

• GHS information (item-specific)

  • Signal word, hazard statements, classification, pictograms: Not specified for this item; refer to SDS.

• General safety profile for low-molecular-weight thiols (literature/good practice; not item-specific specifications)

  • Hazards: typically flammable liquid/vapor; harmful if inhaled or absorbed; causes skin/eye irritation; may cause respiratory irritation; very strong odor at extremely low concentrations.
  • Reactivity: thiols can oxidize to disulfides in air; may form peroxides only if solvent-stabilized ethers are present (thiols themselves are not classical peroxide formers). Avoid strong oxidizers, nitrating agents, and bases/acids that promote exothermic reactions.
  • Incompatibilities: strong oxidizers, acid chlorides/anhydrides (exothermic acylation), alkylating agents (vigorous S-alkylation), and metals that catalyze oxidation.

• Controls & PPE

  • Engineering: work in a well-functioning fume hood; use vapor containment (septum bottles, crimp-sealed vials) to control odor.
  • PPE: lab coat, splash goggles, and chemical-resistant gloves (nitrile/butyl). Consider double-gloving for extended tasks. Use respirator only if required by risk assessment/SDS.

• First aid (overview; defer to SDS)

  • Inhalation: move to fresh air; seek medical attention if symptoms persist.
  • Skin/eye contact: immediate decontamination with water for ≥15 min; remove contaminated clothing; seek medical advice for persistent irritation.
  • Ingestion: rinse mouth; do not induce vomiting; obtain medical attention.

• Fire & spill

  • Use CO2, dry chemical, or foam; water fog for vapor suppression. For spills, ventilate, absorb with inert material, and seal waste promptly to contain odor.

Solvent Selection

This product is a reactive reagent, not a bulk solvent. Nevertheless, practical solvent considerations matter for synthesis and handling.

• Polarity/miscibility (literature/guidance)

  • Expected to be miscible with common organic solvents (ethers, esters, hydrocarbons, chlorinated solvents, alcohols).
  • Limited solubility in water typical for C4 thiols; use co-solvents for aqueous-phase work.

• Choosing media for key transformations

  • Thiol–ene/radical additions: non-protic, low-oxygen media (e.g., toluene, acetonitrile, ethyl acetate) under inert gas; photochemical or AIBN/ACCN-initiated conditions.
  • Nucleophilic substitutions (S-alkylation): polar aprotic solvents (DMF, DMSO, MeCN) enhance rates when converting the thiol to thiolate with base.
  • Additions to epoxides/carbonyl derivatives: alcohols or polar aprotics; base-catalyzed with attention to exotherm.

• Practical handling

  • Store/dispense in tightly sealed containers to limit odor and evaporative loss. For microscale operations, use gas-tight syringes.

• Comparison notes (general)

  • Versus longer-chain thiols (C6+): higher volatility and odor but better reactivity and lower viscosity.
  • Versus aromatic thiols: typically more nucleophilic/basic; faster S-alkylation under comparable conditions.

When solvent purity (water, oxygen) is critical, dry and degas solvents accordingly; consult your reaction’s literature precedent.

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.

• General handling and stability (thiols)

  • Store tightly sealed to minimize volatilization and odor release. Consider inert-atmosphere headspace (nitrogen/argon) to limit air oxidation to disulfide.
  • Protect from strong oxidants and prolonged light exposure. Keep away from bases/acids that could promote side reactions.
  • If long-term storage is anticipated, refrigeration (e.g., 2–8 °C) and amber glass can further slow oxidation; allow to warm to ambient before opening to prevent moisture ingress and pressure differentials.

• Preparation for use

  • Use dry equipment/solvents for base-mediated or radical processes. If required, briefly sparge with inert gas before dispensing.
  • No reconstitution is required; this is supplied as a neat liquid (appearance for this item is not specified—verify on receipt).

Always consult the product’s CoA/Spec Sheet and SDS for definitive guidance on storage, stability, and safe handling. Research use only.

Structure and Identity

Brief description: Methallyl mercaptan is a low‑molecular‑weight, branched allylic thiol (an alkenyl thiol). It combines an isobutenyl (methallyl) fragment with a terminal –SH group, giving a highly nucleophilic and easily oxidized sulfur center.

• Item-specific identifiers (from Product Data)

  • SKU: M1020324
  • CAS: 5954-68-7
  • InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.

• Literature identity (general/reference information; not item-specific specifications)

  • Preferred name: Methallyl mercaptan (2-methyl-2-propen-1-thiol; 2-methylallyl mercaptan)
  • Molecular formula (literature): C4H8S
  • Molecular weight (literature): ~88.17 g/mol
  • Representative SMILES (literature): C=C(C)CS (depicts CH2=C(CH3)–CH2–SH)

• Structural features (general)

  • Functional groups: terminal thiol (–SH), terminal alkene (isobutenyl). No heteroatoms besides sulfur; no stereocenters.
  • 2D description in words: A three-carbon allylic chain bearing a terminal sulfhydryl, with a methyl substituent at the 2-position of the double bond [CH2=C(CH3)–CH2–SH]. The sulfur is primary and directly attached to a methylene carbon, enabling both radical and polar reactivity at sulfur.
  • Resonance/activation: The allylic framework enables radical stabilization in thiol–ene processes; however, the double bond is not conjugated to an electron-withdrawing group (not a classical Michael acceptor).

Synthetic Utility

• Key reactive elements

  • Soft nucleophile (thiol/thiolate) enabling SN2 S‑alkylation, epoxide opening, and conjugate additions.
  • Radical H‑atom donor participating in thiol–ene and thiol–yne additions, useful for late-stage diversification and polymer modification.

• Transformations (literature/general)

  • Formation of methallyl thioethers: R–X (primary) + RS− → R–S–CH2–C(=CH2)–CH3, under K2CO3/DMF or NaH/THF conditions.
  • Hydrothiolation of alkenes/alkynes: photoinitiated or AIBN-initiated additions to install S‑methallyl substituents on unsaturated substrates.
  • Oxidative coupling: 2 RSH → RSSR (controlled with I2, air/metal catalysis), enabling access to the corresponding disulfide.
  • Further oxidation: sulfoxide/sulfone formation under m‑CPBA, Oxone, or H2O2/acetic acid, expanding polarity and stability.
  • Protection chemistry: transient conversion to thioesters (e.g., acetyl) as odor-mitigated carriers, then hydrolysis to regenerate the free thiol.

• Retrosynthetic value

  • Serves as a modular source of the methallylthio motif, which can be leveraged as a latent leaving group or for downstream oxidation to sulfones for Julia‑type or Ramberg–Bäcklund strategies (with appropriate activation).

Handling note: Exclude oxygen/moisture when necessary; verify thiol content prior to use in stoichiometry-sensitive steps.

Target Specificity

This product is a small-molecule thiol reagent, not an affinity reagent or biological binder.

• No antigen/epitope, clone, isotype, or species reactivity applies.
• For selectivity in chemical reactions, see Reaction & Applications and Synthetic Utility for functional-group specificity (nucleophilic/radical reactivity of thiols).