5-Ethynyl-1,3-thiazole - ≥95% , CAS No.872122-41-3

CAS: 872122-41-3 Cat. No.: E1027898 Numéro CE: 821-006-7 PubChem CID: 17875447

GRADE & PURITY ≥95%

Storage

Room temperature

Specifications

Spécifications et pureté

≥95%

Conditions de stockage de stockage

Room temperature

Pureté

≥95%

Noms et identifiants

Sourires canoniques

C#CC1=CN=CS1

IUPAC Name

5-ethynyl-1,3-thiazole

InChIKey

JWFJFVXHZUVMSF-UHFFFAOYSA-N

INCHI

1S/C5H3NS/c1-2-5-3-6-4-7-5/h1,3-4H

Isomères SMILES

C#CC1=CN=CS1

CAS alternatif

872122-41-3

PubChem CID

17875447

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Organoheterocyclic compounds
    • Classe Azoles
      • Subclass Thiazoles

• Kingdom: Organic compounds
• Superclass: Organoheterocyclic compounds
• Classe: Azoles
• Subclass: Thiazoles
• Intermediate Tree Nodes: Not available
• Direct Parent: Thiazoles
• Alternative Parents: Heteroaromatic compounds Azacyclic compounds Acetylides Organopnictogen compounds Organonitrogen compounds Hydrocarbon derivatives
• Molecular Framework: Aromatic heteromonocyclic compounds
• Substituents: Heteroaromatic compound - Thiazole - Acetylide - Azacycle - Organic nitrogen compound - Organopnictogen compound - Hydrocarbon derivative - Organonitrogen compound - Aromatic heteromonocyclic compound
• Description: This compound belongs to the class of organic compounds known as thiazoles. These are heterocyclic compounds containing a five-member aromatic ring made up of one sulfur atom, one nitrogen, and three carbon atoms.
• 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

Propriétés chimiques et physiques

• Poids moléculaire: 109.150 g/mol
• XLogP3: 1.200
• Hydrogen Bond Donor Count: 0
• Hydrogen Bond Acceptor Count: 2
• Rotatable Bond Count: 1
• Exact Mass: 108.999 Da
• Monoisotopic Mass: 108.999 Da
• Topological Polar Surface Area: 41.100 Ų
• Heavy Atom Count: 7
• Formal Charge: 0
• Complexity: 102.000
• 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 tested biological application protocols are provided for this item. As a synthetic building block, typical protocols relate to organic synthesis rather than bioassays.

• General synthetic protocol outlines (for planning only; not item specifications):

  • CuAAC assembly: dissolve 5-ethynyl-1,3-thiazole and an organic azide in t-BuOH/H2O, add CuSO4 and sodium ascorbate (with ligand if needed), stir at RT until completion by LC–MS, then extract/purify.
  • Sonogashira coupling: charge aryl/vinyl halide, this alkyne, Pd catalyst, CuI, and base in dry solvent under N2; heat as needed; work up and purify by column chromatography.

• For detailed, validated procedures: consult primary literature and adapt to your substrate/catalyst system.

• Item-specific tested applications/dilutions: Not specified for this item.

Biological Roles

This product is a synthetic heteroaromatic building block and is not intended for biological administration. No biological roles are specified for this item.

• General context (literature/biochemistry):

  • Thiazole rings occur in natural products and cofactors (e.g., the thiazolium core of thiamine, vitamin B1). However, 5-ethynyl-1,3-thiazole itself is a non-natural fragment.
  • The terminal alkyne can serve as a bio-orthogonal handle in chemical biology when appended to biomolecules via synthetic steps, enabling CuAAC-based labeling under compatible conditions.

• Caution:

  • Do not infer biological safety or activity from structural motifs. This product is for research use only and not for use in humans or animals.

• Item-specific biological data:

  • None provided; Not specified for this item.

Buffer Applications

Not typically applicable. 5-Ethynyl-1,3-thiazole is a small organic building block and not a buffering agent. It does not define a controlled pH range or buffering capacity.

• Practical note:

  • When used in aqueous or mixed-solvent reactions such as CuAAC, choose an appropriate buffer (e.g., phosphate, HEPES) based on the reaction and catalyst system. Ensure the buffer does not coordinate strongly to catalysts or quench reactive intermediates.

• Item-specific buffer data: Not specified for this item.

Green Alternatives

While the substrate itself is a building block, greener choices can be made in its use, particularly in solvent and catalyst selection. The points below are general guidance and not product specifications.

• Greener solvent choices for typical transformations:

  • Replace DMF/DMAc/NMP with MeCN or 2-MeTHF for Sonogashira couplings where feasible.
  • Use aqueous EtOH or t-BuOH/H2O mixtures for CuAAC to reduce reliance on chlorinated solvents.
  • Employ PEG-400 or Cyrene in exploratory couplings where literature precedent supports performance.

• Catalyst/base considerations:

  • Copper-free “click” (e.g., strain-promoted azide–alkyne cycloaddition, if compatible with the system) avoids Cu waste, though it requires strained alkynes and thus is not directly applicable to this unstrained alkyne.
  • Ligand-accelerated low-Pd Sonogashira variants or heterogeneous Pd/C in flow can reduce metal loadings and facilitate recycling (literature).
  • Organic bases (Et3N, DIPEA) in greener solvents can replace inorganic bases in DMF.

• Process intensification:

  • Microwave or flow chemistry may shorten reaction times and lower energy consumption for couplings.

• Brief comparison (general guidance):

  • THF vs 2-MeTHF: 2-MeTHF is bio-derived, higher boiling, and less peroxide-prone; may improve phase separation in workups.
  • DCM vs EtOAc/MeCN: EtOAc/MeCN offer lower environmental impact and simpler waste handling for many extractions/reactions.

Pharmaceutical Uses

No pharmacopeial or excipient status is provided. This compound is intended as a synthetic intermediate in medicinal chemistry workflows, not as a formulated component.

• General formulation/manufacturing context (literature):

  • Heteroaryl alkynes like 5-ethynyl-1,3-thiazole are used in discovery/lead optimization to introduce thiazole motifs and to leverage alkyne reactivity (e.g., triazole formation via CuAAC) for SAR exploration.
  • Any API-related use would involve extensive further synthesis, purification, and regulatory evaluation beyond the scope of this product.

• Compliance and handling:

  • For GMP or clinical manufacturing, additional quality attributes (residual metals, solvent residues, stereochemical purity, trace impurities) must be specified and controlled; these are not provided here.

• Item-specific pharmacopeial status/uses:

  • Not specified for this item; refer to CoA/Spec Sheet.

Physical Properties

Item-specific numerical specifications are not provided in the Product Data. Where helpful, typical literature characteristics for a thiazolyl terminal alkyne are described; these are not product specifications.

• Item-specific values:

  • 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/typical properties of 5-ethynyl-1,3-thiazole (general guidance, not specifications):

  • Molecular formula: C5H3NS (literature)
  • Molecular weight: ~109.15 g/mol (literature)
  • Physical state: low–moderate boiling, volatile heteroaryl alkyne; often a low-melting solid or pale liquid depending on purity (literature/experience; verify on CoA).
  • Solubility: expected to be soluble in common organic solvents (e.g., DCM, EtOAc, THF, MeCN); low water solubility typical for aryl acetylenes (literature).
  • Acidity: terminal alkyne pKa typically ~23–26 in DMSO; heteroaryl substitution can modestly lower pKa vs phenylacetylene (literature, qualitative).
  • Polarity: polar-aprotic character from the thiazole ring; capable of coordinating to metals through N or S in catalysis contexts (literature).

• Values not provided for this item:

  • Boiling point, melting point, density, refractive index, UV cutoff, residual metals, water/peroxide content: Not specified for this item; refer to CoA/Spec Sheet.

Quality and Grades

Item-specific grade/purity is not provided in the Product Data for SKU E1027898.

• Item-specific facts:

  • Grade/purity: Not specified for this item; refer to CoA/Spec Sheet.
  • Stabilizers/additives: Not specified for this item; refer to CoA/Spec Sheet.

• Interpreting common grades (general information):

  • Research grade: suitable for general laboratory synthesis and screening; may not include application-specific guarantees such as low-metal or low-water content.
  • Purified (e.g., 95–98% by NMR/GC/HPLC): typical for building blocks; review chromatographic purity and residual solvents on the CoA.
  • Low-metal grades: beneficial for cross-coupling where trace Pd/Cu contamination can interfere with catalytic cycles or bioassays.
  • Chromatography/HPLC grade (solvents): emphasizes low UV cutoffs and low residue; not directly applicable to this solid/liquid building block.

• Practical guidance:

  • Verify assay method (NMR integration vs GC/HPLC area%) and acceptance criteria.
  • Check for presence/limits of oxidative dimer (Glaser-coupled diyne) or halogenated/byproduct impurities typical of alkyne handling—if reported.
  • If sensitive applications (e.g., fragment screening), request CoA with residual metals, water content, and stabilizer declaration.

Reaction and Applications

5-Ethynyl-1,3-thiazole serves as a versatile heteroaryl terminal alkyne for assembling thiazole-containing scaffolds.

• Representative reaction families (literature/general guidance):

  • Cu-catalyzed azide–alkyne cycloaddition (CuAAC, “click”): formation of 1,2,3-triazoles linking the thiazolyl fragment to azidated partners; compatible with mixed aqueous/organic media.
  • Sonogashira coupling: couples the terminal alkyne to aryl/vinyl halides under Pd/Cu catalysis, enabling ynyl extension or convergent fragment assembly.
  • Glaser–Hay oxidative coupling: homocoupling to furnish diyne dimers; useful as a synthetic handle but an impurity risk under copper/oxygen exposure.
  • Nucleophilic additions after acetylide generation: deprotonation (e.g., n-BuLi) to add to electrophiles (carbonyls, silyl/boron electrophiles) affording propargyl or alkynyl boron/silicon derivatives.
  • Hydrofunctionalizations: hydroboration, hydrosilylation, hydroamination strategies to build diverse vinyl or alkyl derivatives.

• Heteroatom effects (general):

  • The thiazole can coordinate to transition metals, sometimes modifying catalytic rates/selectivity.
  • Electron-deficient character of thiazole can slightly tune alkyne acidity/reactivity compared to phenylacetylenes.

• Practical tips:

  • Minimize copper/air exposure during storage to limit Glaser dimer formation.
  • For CuAAC, ensure chelation control (use of ligands like TBTA/THPTA) to moderate copper levels where sensitive functionality is present.
  • For Sonogashira, preclude halide scavengers that might deactivate catalysts; degas solvents and use dry conditions for best results.

Reaction Conditions

Typical literature conditions for common transformations of 5-ethynyl-1,3-thiazole are summarized below. These are general guidelines and not product specifications; optimize for your substrate set.

• CuAAC (azide–alkyne “click”):

  • Catalyst: CuSO4·5H2O (1–5 mol%) plus sodium ascorbate (5–20 mol%) to generate Cu(I) in situ; optional ligands (TBTA/THPTA) to stabilize copper.
  • Solvent: t-BuOH/H2O (1:1) or EtOH/H2O; temperature: RT to 60 °C; time: 0.5–12 h.
  • Typical outcomes: high regioselectivity to 1,4-triazoles; isolated yields often 70–95% in small-molecule systems (literature ranges).

• Sonogashira coupling (to aryl/vinyl halides):

  • Catalyst: Pd(PPh3)2Cl2 (1–3 mol%) with CuI (2–10 mol%); base: Et3N or i-Pr2NH.
  • Solvent: THF, MeCN, 2-MeTHF, or DMF; temperature: RT–80 °C; atmosphere: N2/Ar; time: 1–16 h.
  • Notes: copper-free variants (Pd only, phosphine or NHC ligands) reduce Glaser coupling risk.

• Acetylide additions:

  • Base: n-BuLi or LDA (1.05–1.2 equiv) at −78 to −20 °C in dry THF; electrophiles: aldehydes, ketones, Me3SiCl, B(OR)3 derivatives.
  • Quench: NH4Cl or aqueous workup; typical yields 50–85% depending on electrophile (literature ranges).

• Glaser–Hay homocoupling (intentional):

  • CuCl/CuI (5–10 mol%), TMEDA or amine base, O2 or air; solvent: toluene, THF; temperature: RT–60 °C; forms diyne.

• Safety/handling during reactions:

  • Degas solvents; exclude moisture/air where base-sensitive steps are used; monitor by TLC/LC–MS.

Safety and Handling

No GHS classification data are supplied in the Product Data. Always consult the product-specific SDS for authoritative hazard information and local regulatory requirements.

• Item-specific hazard fields (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 considerations for terminal alkynes and thiazoles (literature/general guidance):

  • Flammability/volatility: many small alkynes are flammable and volatile; prevent ignition sources and manage vapors in a fume hood.
  • Irritation/sensitization: heteroaromatic compounds may cause skin/eye/respiratory irritation; minimize exposure.
  • PPE: lab coat, chemical-resistant gloves (e.g., nitrile), safety goggles; use in a well-ventilated fume hood.
  • Incompatibilities: strong oxidizers; strong bases can deprotonate the terminal alkyne generating reactive acetylides; copper salts plus O2 may promote undesired Glaser coupling.
  • First aid (overview; defer to SDS): move to fresh air if inhaled; rinse skin/eyes with water for 15 minutes; seek medical attention if symptoms persist; remove contaminated clothing.
  • Spill response: absorb with inert material, avoid ignition sources, ventilate area; collect for disposal per institutional guidelines.

• Storage notes:

  • Follow item-specific direction: Room temperature.
  • General precautions: keep tightly closed, under dry, inert atmosphere if possible to limit oxidative coupling; store away from bases and oxidants (general guidance).

Solvent Selection

As a small heteroaryl terminal alkyne, 5-ethynyl-1,3-thiazole generally dissolves in a range of polar aprotic and moderately polar organic solvents. Item-specific solubility data are not provided and should be verified experimentally.

• Polarity/miscibility (general):

  • Likely good solubility in DCM, EtOAc, THF, MeCN, acetone; variable in alcohols; poor in water.
  • The thiazole ring imparts some polarity and metal-binding character relative to simple arylacetylenes.

• Use-case guidance:

  • Cross-coupling (e.g., Sonogashira): amine bases/solvents (Et3N, i-Pr2NH) or polar aprotics (DMF, DMAc, NMP) to stabilize catalysts; greener options include 2-MeTHF or MeCN.
  • Click chemistry (CuAAC): mixed t-BuOH/H2O, EtOH/H2O, or MeCN/H2O are commonly effective; ensure adequate cosolvent if hydrophobic partners are used.
  • Lithiation/acetylide formation: ethereal solvents (THF) at low temperature under inert atmosphere.

• Selection comparison (general):

  • THF: good for base-mediated steps; peroxide formation risk in storage—monitor and use inhibitors where relevant.
  • 2-MeTHF: greener, higher boiling, more hydrophobic; often substitutes for THF in couplings.
  • MeCN: polar, low viscosity, easy removal; supports many Pd/Cu-catalyzed reactions.
  • DMF/DMAc: strong solvating power; consider worker exposure and waste minimization.

• Item-specific solubility specs: Not specified for this item; refer to CoA/Spec Sheet.

Storage and Reconstitution

Follow the item-specific storage guidance and standard practices for small reactive alkynes.

• Item-specific storage (from Product Data):

  • Storage conditions: Room temperature.
  • Shipped in: Not specified for this item; refer to CoA/Spec Sheet.
  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.

• General storage guidance (not a specification):

  • Keep container tightly closed in a dry, well-ventilated place.
  • Protect from prolonged exposure to air and light; consider storing under inert gas for long-term stability to minimize oxidative coupling (Glaser) in the presence of trace copper.
  • Segregate from strong oxidizers and strong bases.

• Reconstitution/use:

  • If solid, dissolve in a suitable dry organic solvent (e.g., THF, DCM, MeCN) just prior to use.
  • If liquid, dispense by gas-tight syringe under inert atmosphere for air- and moisture-sensitive operations.

• Stability notes:

  • No item-specific shelf-life or stabilizer data are provided; Not specified for this item—refer to CoA/Spec Sheet.

• Regulatory note:

  • For research use only. Not for human or animal use.

Structure and Identity

A heteroaromatic terminal alkyne combining a 1,3-thiazole ring with an ethynyl substituent at C5.

• Item-specific (from Product Data):

  • CAS: 872122-41-3
  • Product name: 5-Ethynyl-1,3-thiazole
  • InChIKey: 171755
  • Storage: Room temperature
  • Research use note: For research use only

• Literature/derived identifiers (for reference; not item specifications):

  • Molecular formula (literature): C5H3NS
  • Molecular weight (literature): ~109.15 g/mol
  • IUPAC-style name (descriptive): thiazol-5-ylethyne
  • Structural features: a five-membered 1,3-thiazole (N at position 3, S at position 1) bearing a terminal alkyne (–C≡CH) at the C5 position.

• 2D structural description (general):

  • The thiazole ring consists of two heteroatoms (S at position 1, N at position 3) and three sp2 carbons; C5 carries the substituent.
  • The substituent is an ethynyl group, featuring an sp-hybridized carbon-carbon triple bond terminating in a hydrogen (terminal alkyne). The acetylenic proton is acidic relative to typical sp2/sp3 C–H bonds.

• SMILES/InChI:

  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
  • Full InChI: Not specified for this item; refer to CoA/Spec Sheet.

Synthetic Utility

The coexistence of a terminal alkyne and a thiazole ring makes 5-ethynyl-1,3-thiazole a compact, functionally rich synthon.

• Functional group leverage (literature/general):

  • Terminal alkyne (–C≡CH): platform for C–C bond construction (CuAAC, Sonogashira, alkynylations), selective reductions (to Z/E-alkenes or alkanes), cycloadditions, and metal-mediated additions after deprotonation.
  • Thiazole ring: electron-poor, heteroatom-rich unit imparting H-bond acceptors (N) and soft-donor character (S); participates in π–π and heteroatom interactions in ligands/materials.

• Retrosynthetic value:

  • Convergent access to thiazolyl-triazoles via CuAAC with azidated fragments.
  • Rapid assembly of diaryl- or heteroaryl-acetylenes through Sonogashira with aryl/vinyl halides/triflates.
  • Formation of vinyl boronates/silanes via hydroboration/hydrosilylation of the alkyne for iterative cross-coupling strategies.

• Protecting/compatibility considerations:

  • The terminal alkyne can be masked as TMS-alkyne and unveiled by mild deprotection (TBAF, K2CO3/MeOH); conversely, this substrate already provides the terminal handle for direct use.
  • Avoid prolonged exposure to Cu/O2 in basic media to minimize Glaser dimer formation.

• Downstream diversification:

  • Electrophilic halogenation or metalation on the thiazole ring (at positions other than C5) can further elaborate the core in multi-directional syntheses.

Target Specificity

Not applicable. This product is a small-molecule building block and is not an antibody, probe, or biologic with defined target specificity.

• Item-specific target/epitope/clone/isotype data: Not specified for this item.

Foire aux questions

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 872122-41-3. InChIKey JWFJFVXHZUVMSF-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.