2-Ethynylbenzaldehyde - ≥96% , CAS No.38846-64-9

CAS: 38846-64-9 Cat. No.: E193142 Formule: C₉H₆O Poids moléculaire: 130.14 Numéro CE: 627-720-3

QUALITÉ & PURETÉ ≥96%

Synonyms

Benzaldehyde,2-ethynyl-|2-ethynylbenzaldehyde|2-ethynyl-benzaldehyde|benzaldehyde, 2-ethynyl-|ethynyl benzaldehyde

Storage

Room temperature,Argon charged

Shipped In

Normal

Vue d’ensemble

2-Ethynylbenzaldehyde may be used in the synthesis of the following: • iodoisoquinoline-fused benzimidazoles obtained via tandem iodocyclization of 2-ethynylbenzaldehyde with o-benzenediamine and iodine in the presence of copper(I)iodide • N-[(7,7a-dihydroisoquinolino[2,1-a]perimidin-13-yl)methyl]-N-isopropylpropan-2-amine obtained via a multi-step process It may also be used in the synthesis of the following substituted 2-alkynylbenzaldehydes by Sonogashira coupling: • 2-[(2-bromophenyl)ethynyl]benzaldehyde • 2-[(2-bromo-5-fluorophenyl)ethynyl]benzaldehyde • 2-[(2-bromo-5-methylphenyl)ethynyl]benzaldehyde • 2-(phenylethynyl)benzaldehyde • 2-[(4-methylphenyl)ethynyl]benzaldehyde

Spécifications

Synonymes

Benzaldehyde,2-ethynyl- | 2-ethynylbenzaldehyde | 2-ethynyl-benzaldehyde | benzaldehyde, 2-ethynyl- | ethynyl benzaldehyde

Spécifications et pureté

≥96%

Conditions de stockage de stockage

Room temperature,Argon charged

Expédié en

Normal

Pureté

≥96%

Noms et identifiants

Pubchem Sid

504759685

Pubchem Sid Url

https://pubchem.ncbi.nlm.nih.gov/substance/504759685

Sourires canoniques

C#CC1=CC=CC=C1C=O

IUPAC Name

2-ethynylbenzaldehyde

InChIKey

ZEDSAJWVTKUHHK-UHFFFAOYSA-N

INCHI

1S/C9H6O/c1-2-8-5-3-4-6-9(8)7-10/h1,3-7H

Isomères SMILES

C#CC1=CC=CC=C1C=O

WGK Allemagne

3

Poids moléculaire

130.14

Reaxy-Rn

2612483

Reaxys-RN_link_address

https://www.reaxys.com/reaxys/secured/hopinto.do?context=S&query=IDE.XRN=2612483&ln=

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Benzenoids
    • Classe Benzene and substituted derivatives
      • Subclass Benzoyl derivatives

• Kingdom: Organic compounds
• Superclass: Benzenoids
• Classe: Benzene and substituted derivatives
• Subclass: Benzoyl derivatives
• Intermediate Tree Nodes: Not available
• Direct Parent: Benzoyl derivatives
• Alternative Parents: Benzaldehydes Acetylides Organic oxides Hydrocarbon derivatives
• Molecular Framework: Aromatic homomonocyclic compounds
• Substituents: Benzoyl - Benzaldehyde - Aryl-aldehyde - Acetylide - Organic oxygen compound - Organic oxide - Hydrocarbon derivative - Organooxygen compound - Aldehyde - Aromatic homomonocyclic compound
• Description: This compound belongs to the class of organic compounds known as benzoyl derivatives. These are organic compounds containing an acyl moiety of benzoic acid with the formula (C6H5CO-).
• 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

Mécanismes d'action

Propriétés chimiques et physiques

• Sensibilité: air sensitive
• Point de fusion (°C): 63 °C
• Poids moléculaire: 130.139 g/mol
• XLogP3: 2.000
• Hydrogen Bond Donor Count: 0
• Hydrogen Bond Acceptor Count: 1
• Rotatable Bond Count: 2
• Exact Mass: 130.042 Da
• Monoisotopic Mass: 130.042 Da
• Topological Polar Surface Area: 17.100 Ų
• Heavy Atom Count: 10
• Formal Charge: 0
• Complexity: 163.000
• 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

Not applicable. No biological assay protocols (e.g., WB, IHC, IF, FC) are associated with this chemical building block. For practical use, see the Reaction Conditions and Application examples under Reaction & Applications and Synthetic Utility.

Biological Roles

This product is intended strictly for research and laboratory use. No biological role is assigned in vivo.

• General chemistry context (not product-specific claims):
  • Aromatic aldehydes can act as electrophiles toward biomolecular nucleophiles in vitro (e.g., amines), forming imines/Schiff bases; this underlies common bioconjugation strategies but is not a biological function per se.
  • Terminal alkynes are handles for bioorthogonal transformations after suitable derivatization (e.g., CuAAC once converted to an internal alkyne/azide partner), enabling probe synthesis for biochemical studies.

No clinical, diagnostic, or therapeutic uses are implied or supported. For any work involving biological systems, ensure appropriate risk assessments and approvals.

Buffer Applications

Not typically applicable. 2-Ethynylbenzaldehyde is a hydrophobic organic building block and is not used to prepare aqueous buffer systems. For laboratory work, focus on the Reaction & Applications, Synthetic Utility, and Reaction Conditions sections for relevant guidance.

Green Alternatives

As a reactive building block, 2-ethynylbenzaldehyde itself is not readily substituted; however, greener choices can be made for solvents, reagents, and catalysts used with it.

• Greener solvent choices (literature-based guidance):
  • Replace chlorinated solvents (DCM/DCE) with 2-methyltetrahydrofuran (2-MeTHF), cyclopentyl methyl ether (CPME), or ethyl acetate when compatible with catalyst and reaction kinetics.
  • For organometallic additions, 2-MeTHF can substitute for THF/Et2O in many Grignard and hydride reductions, offering improved safety and biorenewable sourcing.
• Benign reagents and conditions:
  • Use aqueous-compatible olefination protocols (e.g., Wittig variants in greener ethers/esters) and supported catalysts to simplify workup.
  • Prefer catalytic hydrogenation or transfer hydrogenation (e.g., formic acid/amine systems) for reductive aminations over stoichiometric borohydrides when feasible.
  • Employ gold catalysts at low loading with recyclable ligands/supports for cycloisomerizations; explore Brønsted acid catalysis as a metal-free alternative where scope permits.
• Process intensification and waste minimization:
  • Telescoping: Condense imine formation and cyclization in one pot to reduce solvent exchanges.
  • Solvent recovery: choose higher-boiling green ethers (CPME/2-MeTHF) to facilitate distillation and reuse.

Comparison snapshot (general):

• DCM/DCE: excellent for carbocationic/gold catalysis; environmental and toxicity concerns.
• 2-MeTHF/CPME: greener, hydrophobic ethers; may require longer times or higher temperatures but often provide comparable selectivity for o-alkynyl benzaldehyde cyclizations.

Pharmaceutical Uses

This substance is not an excipient or approved additive. It is supplied for research use only.

• Formulation context (general, non-clinical):
  • As a synthetic intermediate, o-alkynyl benzaldehydes are sometimes used in discovery chemistry to construct polycyclic or heteroaromatic motifs. Any such use remains within preclinical synthetic workflows.
  • No pharmacopeial monographs or compendial grades are associated with this item (grade/purity: Not specified for this item; refer to CoA/Spec Sheet).

No therapeutic, diagnostic, or clinical claims are made.

Physical Properties

• Item-specific specs: Not specified for this item; refer to CoA/Spec Sheet.
• Literature/general properties for 2-ethynylbenzaldehyde (reference only; not product specifications):
  • Physical state: typically a pale to colorless liquid at ambient conditions (literature observations for analogous o-alkynyl benzaldehydes).
  • Molecular formula: C9H6O; formula weight ~130.14 g/mol (literature).
  • Polarity/functional profile: moderately polar due to the aldehyde; aromatic-alkynyl scaffold confers hydrophobic character.
  • Solubility (qualitative, literature):
    • Organic solvents: expected to be miscible or highly soluble in common organics such as dichloromethane, toluene, ethyl acetate, THF, acetonitrile.
    • Aqueous: very low water solubility typical of aromatic aldehydes.
  • Volatility: lower than benzaldehyde due to increased π-surface; may show a relatively high boiling range (literature trend for o-alkynyl aromatics).
  • Acidic proton: terminal alkyne pKa typically ~25 (in DMSO, literature for phenylacetylene-like systems); aldehyde has no dissociable proton.
  • LogP: expected in the low-to-mid 2 range (literature estimates for aromatic aldehydes bearing C≡C), indicating moderate hydrophobicity.
  • Spectroscopic handles (general): strong IR C=O stretch near ~1690–1720 cm⁻1 and terminal alkyne ≡C–H stretch near ~3300 cm⁻1; 13C signals for carbonyl (~190–195 ppm) and sp carbons (~70–90 ppm) (literature ranges).

Note: Numeric boiling/melting points, density, refractive index, and UV cutoffs are not specified for this item; consult the CoA/SDS for exact values.

Quality and Grades

• Item-specific grade/purity: Not specified for this item; refer to CoA/Spec Sheet.
• Practical implications (general guidance for this compound class):
  • For synthesis and catalysis (e.g., gold- or palladium-catalyzed cyclizations, organometallic additions), low levels of peroxides, acids, and water are preferred to avoid catalyst poisoning or side reactions (e.g., aldol/self-condensation). If grade is unspecified, consider in-lab purification (distillation under reduced pressure, short-path) immediately before use.
  • Chromatography-grade material may reduce background in analytical monitoring (HPLC/GC) but is not a substitute for drying/degassing if moisture/oxygen-sensitive steps are planned.
• Stabilizers: Not specified for this item; refer to CoA/Spec Sheet. If supplied inhibitor-free, aldehydes can slowly oxidize; inert gas headspace (argon-charged per Product Data) mitigates this.
• Verification: Confirm identity/purity by 1H/13C NMR, GC–MS/LC–MS, and IR (diagnostic C=O and ≡C–H stretches). Retain the batch CoA for method-specific acceptance criteria in your lab’s SOPs.

Reaction and Applications

2-Ethynylbenzaldehyde is a versatile o-alkynyl aromatic aldehyde enabling intramolecular cyclizations and diverse carbon–carbon and carbon–heteroatom bond formations.

• Carbonyl chemistry:
  • Nucleophilic additions (RMgX/RLi) to give propargylic alcohols; subsequent oxidation or cyclization elaborates to benzofurans/indenones (literature precedents).
  • Imine/enamine formation with amines, enabling reductive amination or intramolecular annulations with the proximal alkyne under acid/gold catalysis.
  • Wittig/HWE/Julia–Kocienski olefinations install vinyl substituents adjacent to the alkyne for elaborated scaffolds.
• Alkyne-enabled annulations and cycloisomerizations:
  • Gold(I/III)-catalyzed cycloisomerization of o-alkynyl benzaldehydes furnishes isochromenes, benzopyrans, or indenone derivatives depending on nucleophile and catalyst/acid (literature).
  • Brønsted or Lewis acid-promoted intramolecular nucleophilic attack of the aldehyde onto the activated alkyne yields cyclic acetals/oxocarbenium intermediates en route to benzofurans and related heterocycles.
• Cross-coupling and C–H activation (on suitably derivatized analogs):
  • Sonogashira coupling on halogenated derivatives to extend the alkyne; subsequent carbonyl transformations broaden diversity.
• Cascade strategies:
  • One-pot sequences combining imine formation, alkyne activation, and cyclization streamline access to polycyclic frameworks (e.g., indenones, isochromenes).
• Orthogonal reactivity:
  • Terminal alkyne allows click-type conjugations after azide installation (via prior conversion to an internal alkyne/azide partner), while aldehyde remains a handle for selective derivatization under mild conditions.

Practical notes: Maintain inert atmosphere (argon per Product Data). Dry conditions and acid/base choices are crucial to direct chemoselectivity between alkyne activation and carbonyl reactions.

Reaction Conditions

General literature guidance for transformations involving 2-ethynylbenzaldehyde (reference only; adjust to your substrate/catalyst system). These are not product specifications.

• Nucleophilic addition to the aldehyde (e.g., RMgX/RLi):
  • Solvent: dry THF or Et2O; 0 to −78 °C for addition, then warm to 0–25 °C.
  • Atmosphere: inert (argon or nitrogen). Quench with saturated NH4Cl. Typical isolations yield good to excellent conversions to propargylic alcohols.
• Reductive amination:
  • Solvent: toluene, MeOH, or EtOH; molecular sieves (3Å) to drive imine formation.
  • Reductant: NaBH3CN or catalytic hydrogenation (Pd/C, H2, 1–3 bar). Room temperature to 60 °C.
• Wittig/Horner–Wadsworth–Emmons olefination:
  • Base: t-BuOK/NaHMDS for stabilized ylides; temperature −78 to 25 °C.
  • Solvent: THF, DCM, or toluene depending on ylide stability.
• Gold-catalyzed cycloisomerization to benzannulated products (isochromenes/indenones):
  • Catalyst: Ph3PAuNTf2 (1–5 mol%) or AuCl3 (2–10 mol%) with/without Brønsted acid co-catalyst (e.g., HOTf, TfOH 1–10 mol%).
  • Solvent: DCM/DCE, toluene, or 2-MeTHF; 0–60 °C; 0.5–6 h typical.
• Acid-promoted cyclizations (metal-free):
  • Brønsted acids (e.g., TsOH, TfOH catalytic) in toluene or DCE; 25–80 °C.
• Oxidation/reduction of the aldehyde:
  • Oxidation to acid: Oxone/TEMPO or Pinnick conditions (NaClO2, NaH2PO4, 2-methyl-2-butene) in t-BuOH/H2O; 0–25 °C.
  • Reduction to alcohol: NaBH4 or DIBAL-H in MeOH/THF at 0–25 °C.

Notes: Monitor by TLC/GC–MS/LC–MS. Control proton sources to avoid unwanted acetylide formation. Adjust catalyst loading and temperature to manage chemoselectivity between alkyne activation and carbonyl reactions.

Safety and Handling

• Regulatory/SDS note: GHS classification, hazard statements, and pictograms are not provided in the Product Data for this item. Always consult the product-specific SDS for authoritative safety information.
• General hazards for aromatic aldehydes and terminal alkynes (literature-based guidance):
  • Aldehydes can be irritating to eyes, skin, and respiratory tract; may cause sensitization in susceptible individuals upon prolonged exposure.
  • Combustible organic liquid; vapors may form flammable mixtures with air at elevated temperatures.
  • Terminal alkynes can form metal acetylides with strong bases/alkoxides and reactive metals; avoid incompatible bases unless intended.
• Recommended PPE and controls:
  • Use in a chemical fume hood. Wear safety glasses or splash goggles, lab coat, and appropriate chemical-resistant gloves (e.g., nitrile). Consider double-gloving for extended contact tasks.
  • Avoid inhalation of vapors/aerosols; prevent skin contact. Use closed-transfer techniques or septum-equipped bottles for air/moisture-sensitive manipulations.
• Incompatibilities (general):
  • Strong oxidizers (risk of exothermic reactions/over-oxidation), strong bases (formation of acetylides), strong reducing agents (undesired reduction of the aldehyde).
• First-aid overview (defer to SDS for full steps):
  • 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 evaluation for persistent irritation.
  • Ingestion: rinse mouth; do not induce vomiting; seek medical advice.
• Storage precaution from Product Data: store at room temperature under argon (argon charged). Keep container tightly closed, dry, and protected from light to minimize oxidation/polymerization.

Solvent Selection

This product is a reactive building block rather than a solvent. Selection below refers to choosing an appropriate reaction medium for 2-ethynylbenzaldehyde in synthesis.

• Polarity and miscibility considerations (general):
  • Moderately polar substrate; dissolves well in common organic solvents (e.g., DCM, toluene, THF, MeCN, EtOAc). Poorly soluble in water.
• Typical solvent choices by transformation:
  • Nucleophilic additions (e.g., Grignard, organolithium): dry THF or diethyl ether; rigorously anhydrous, inert atmosphere.
  • Reductive amination/imine formation: toluene, DCM, or MeOH/EtOH with molecular sieves; MeCN for more polar amines.
  • Wittig/olefinations: toluene, THF, or DCM depending on ylide stability.
  • Gold- or Brønsted acid-catalyzed cyclizations: DCM, DCE, or toluene; for greener profiles, 2-MeTHF or CPME may be viable.
  • Cross-couplings on prefunctionalized derivatives (e.g., halogenated variants): dioxane/H2O or toluene with Pd catalysts; base selection tailored to alkyne compatibility.
• Practical tips:
  • Remove dissolved oxygen for sensitive catalysis (sparge with argon or nitrogen). Dry solvents over molecular sieves (3Å or 4Å) as needed.
  • Avoid strongly basic aqueous media that may generate metal acetylides; if base is required, use controlled amounts in an aprotic solvent.

Storage and Reconstitution

• Storage (item-specific): Room temperature, argon charged (per Product Data). Keep tightly sealed under inert gas to minimize oxidation or polymerization. Store dry and away from light/heat sources.
• Shipping: Normal (per Product Data).
• Stability considerations (general for aldehydes/alkynes):
  • Aldehydes can slowly oxidize to acids; minimize headspace oxygen (argon blanket), and consider refrigeration for long-term storage if compatible with your SOPs.
  • Avoid prolonged exposure to strong bases; terminal alkynes can form metal acetylides.
• Handling:
  • Use air-free techniques (syringe/septum) for sensitive transformations.
  • If discoloration or odor change suggests oxidation, purify by short-path distillation under reduced pressure or by rapid column chromatography.
• Reconstitution: Not applicable; supplied neat. If a solution is required, prepare freshly in a dry, oxygen-free solvent (e.g., anhydrous DCM, THF, toluene) immediately prior to use.
• Research Use Note: For research use only.

Structure and Identity

Aromatic o-alkynyl aldehyde building block useful for heterocycle constructions and C–C bond-forming reactions.

• Item-specific identifiers (from Product Data):
  • SKU: E193142
  • Product Name: 2-Ethynylbenzaldehyde
  • CAS: 38846-64-9
  • CID: 640368
  • InChIKey: 454537 (as provided for this item)
  • Category Path: 全部 / 可售 / 化学和生化试剂
• Literature structural data (for reference; not item-specific):
  • Molecular formula: C9H6O (literature)
  • Molecular weight: ~130.14 g/mol (literature)
  • Preferred IUPAC name: 2-ethynylbenzaldehyde (o-ethynylbenzaldehyde) (literature)
  • Canonical SMILES: C#Cc1ccccc1C=O (literature)
• Structural features and 2D description (general chemistry):
  • Consists of a benzene ring bearing two ortho substituents: an aldehyde (–CHO) and a terminal alkyne (–C≡CH) directly adjacent on the ring.
  • Functional groups: aromatic ring, aldehyde (electrophilic carbonyl), terminal alkyne (acidic C–H, π-system for cyclizations and additions).
  • The ortho relationship enables intramolecular cyclizations (e.g., benzannulations, heteroannulations) via nucleophilic or π-activation of the alkyne with the proximal aldehyde.
  • No stereocenters; planar aromatic core with linear alkyne.

Synthetic Utility

Key functional elements: an electrophilic aldehyde and a terminal alkyne in an ortho relationship on an aromatic ring. This adjacency enables both orthogonal and cooperative reactivity.

• Orthogonal transformations:
  • Aldehyde handle: imine/enamine formation, Wittig and HWE olefinations, nucleophilic additions (RMgX/RLi), oxidation to acid, reduction to benzyl alcohol.
  • Alkyne handle: metal-catalyzed additions (Au, Pt), hydrofunctionalizations, Glaser coupling (after conversion to a halo or protected derivative), cycloadditions (after derivatization).
• Cooperative/cascade chemistry:
  • Intramolecular cyclizations to indenones, benzofurans, and isochromenes via activation of the alkyne and nucleophilic participation of the aldehyde (often Au-catalyzed or Brønsted acid-promoted).
  • Redox-neutral annulations with external nucleophiles (alcohols, water, arenes) to elaborate oxygenated benzannulated frameworks.
• Retrosynthetic value:
  • Strategic disconnection to access benzofused cores common in materials and medicinal chemistry scaffolds.
  • Serves as a linchpin for late-stage diversification: the aldehyde can be transformed without perturbing the alkyne, or vice versa, enabling library synthesis.
• Protective group strategies:
  • Temporary protection of the aldehyde as an acetal (e.g., ethylene glycol/acid) enables alkyne-specific chemistry under basic or metal-catalyzed conditions; deprotect under mild acid.

Practical: Maintain inert atmosphere to limit oxidative degradation; dry solvents and exclude strong bases unless acetylide formation 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 species reactivity information applies.

Foire aux questions

What is the purity of this product?

This product is supplied at ≥96% purity (chemical assay). Lot-specific values are stated on the Certificate of Analysis.

How should this product be stored?

Store at room temperature under argon. It is supplied under an argon blanket; reseal under inert gas after each use.

How is this product shipped?

This product ships under standard ambient conditions. No temperature-controlled packaging is required.

What are the CAS number, molecular formula and molecular weight?

The CAS Number is 38846-64-9, the molecular formula is C9H6O, and the molecular weight is 130.14 g/mol. InChIKey ZEDSAJWVTKUHHK-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.