2-Ethynyl-5,8-dioxaspiro(3.4)octane - ≥98% , CAS No.1392803-25-6

CAS: 1392803-25-6 Cat. No.: E1004876 Formula: C₈H₁₀O₂ Peso molecolare: 138.16 Numero EC: 882-911-0 PubChem CID: 72208254

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: C#CC1CC2(C1)OCCO2
• IUPAC Name: 2-ethynyl-5,8-dioxaspiro[3.4]octane
• InChIKey: VPUXPPJOFRHHAQ-UHFFFAOYSA-N
• INCHI: 1S/C8H10O2/c1-2-7-5-8(6-7)9-3-4-10-8/h1,7H,3-6H2
• Isomeri SMILES: C#CC1CC2(C1)OCCO2
• PubChem CID: 72208254
• Peso molecolare: 138.16

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Organic oxygen compounds
    • Classe Organooxygen compounds
      • Subclass Ethers
        • Level5 Acetals
          • Level6 Ketals

• Kingdom: Organic compounds
• Superclass: Organic oxygen compounds
• Classe: Organooxygen compounds
• Subclass: Ethers
• Intermediate Tree Nodes: Acetals
• Direct Parent: Ketals
• Alternative Parents: 1,3-dioxolanes Oxacyclic compounds Acetylides Hydrocarbon derivatives
• Molecular Framework: Aliphatic heteropolycyclic compounds
• Substituents: Ketal - Meta-dioxolane - Acetylide - Oxacycle - Organoheterocyclic compound - Hydrocarbon derivative - Aliphatic heteropolycyclic compound
• Descrizione: This compound belongs to the class of organic compounds known as ketals. These are acetals derived from ketones by replacement of the oxo group by two hydrocarbyloxy groups R2C(OR)2 ( R not Hydrogen ). This term, once abandoned, has been reinstated as a subclass of acetals.
• 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: 138.160 g/mol
• XLogP3: 0.500
• Hydrogen Bond Donor Count: 0
• Hydrogen Bond Acceptor Count: 2
• Rotatable Bond Count: 0
• Exact Mass: 138.068 Da
• Monoisotopic Mass: 138.068 Da
• Topological Polar Surface Area: 18.500 Ų
• Heavy Atom Count: 10
• Formal Charge: 0
• Complexity: 175.000
• 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 assay- or kit-style protocols are specified for this catalog item. It is a general-purpose synthetic reagent.

• Example operational outlines (general, non-binding):
  • CuAAC coupling: Dissolve alkyne (1.0 eq) and azide (1.0–1.2 eq) in t‑BuOH/H2O (1:1, 0.1 M). Add CuSO4 (2 mol%) and sodium ascorbate (5 mol%), optionally TBTA (2–5 mol%). Stir at rt under N2 2–6 h, monitor by LC–MS. Extract with EtOAc, wash with EDTA solution, dry, and purify.
  • Sonogashira coupling: In dry DMF with iPr2NH under N2, combine aryl bromide (1.0 eq), Pd(PPh3)2Cl2 (2 mol%), CuI (2 mol%). Add the alkyne (1.2 eq). Heat 50–60 °C 4–12 h. Quench, extract, and purify by silica gel chromatography.

These are illustrative literature-style workflows and must be optimized for your substrate, scale, and safety requirements. Always perform appropriate controls, and consult the SDS/CoA for this SKU before use.

Biological Roles

This product is a synthetic organic building block intended for research and laboratory use. No endogenous biological role is assigned.

• General context (not product-specific):

  • Terminal alkynes are widely used as bioorthogonal handles in chemical biology via Cu-catalyzed azide–alkyne cycloaddition (CuAAC) to tag biomolecules post-synthetically.
  • Acetal motifs can act as protecting groups for carbonyl compounds and polyols during the synthesis of bioactive molecules, carbohydrates, and natural product fragments.

• Potential research relevance:

  • The compact spiroacetal may serve as a conformational element in probe design, offering rigidity and oxygenated polarity without H-bond donors.
  • The alkyne tag allows subsequent conjugation to fluorophores, affinity labels, or polymer backbones under mild conditions compatible with many biomolecules (after prior installation onto the molecule of interest).

No clinical, diagnostic, or therapeutic claims are made. For any use involving live cells or biomacromolecules, evaluate cytocompatibility and solvent system independently. Always adhere to institutional biosafety and chemical safety guidelines.

Buffer Applications

This compound is a hydrophobic organic building block and is not a buffer component. It does not provide acid/base conjugate pairs suitable for maintaining pH in aqueous systems.

• Practical guidance:
  • If performing bioconjugation (e.g., CuAAC) in aqueous media, select an appropriate buffer such as PBS (pH 7.2–7.4), HEPES (pH 7.0–8.0), or Tris (pH 7.5–8.5), ensuring the compound is first dissolved in a miscible cosolvent (t‑BuOH, DMSO, or MeCN) before addition to the buffer.
  • Avoid acidic buffers if acetal integrity must be preserved; acetals can hydrolyze under acidic aqueous conditions.

Refer to click-chemistry literature for buffer/cosolvent ratios compatible with your biological system. This guidance is general and not product-specific.

Green Alternatives

Being a specialty building block, the greener choices relate primarily to solvent/catalyst selection and reaction design rather than replacing the molecule itself.

• Greener solvent options (literature/general):

  • Prefer 2‑MeTHF, cyclopentyl methyl ether (CPME), EtOAc, or MeCN over chlorinated solvents where feasible.
  • For CuAAC, aqueous t‑BuOH/H2O or PEG‑400/H2O mixtures can reduce VOC emissions vs neat organic media.

• Catalysis and process intensification:

  • Copper-free Sonogashira (Pd with amine base, or photoredox/Ni dual catalysis) avoids Cu-derived Glaser coupling and reduces metal waste.
  • Flow chemistry for click and coupling reactions improves heat/mass transfer, allowing lower catalyst loadings and safer handling of azides.

• Workup/waste minimization:

  • Use solid-supported catalysts to simplify separation.
  • Apply solvent swaps to greener choices for crystallization or extraction (e.g., heptane/EtOAc) and recover solvents by distillation.

• Comparative snapshot (general; not product-specific):

  • DCM vs EtOAc: EtOAc is biodegradable, lower toxicity, but may require larger volumes to dissolve highly nonpolar substrates.
  • THF vs 2‑MeTHF: 2‑MeTHF is bio-derived, higher bp aids recovery, and forms fewer peroxides; may alter selectivity/solubility in metalations.

Note: Validate greener substitutions on small scale to confirm compatibility with the spiroacetal (acid/base sensitivity) and alkyne (coupling efficiency).

Pharmaceutical Uses

No pharmacopeial monograph or excipient designation is provided for this item. It is sold strictly for research use only.

• General formulation context (not product-specific):

  • Terminal alkyne building blocks are frequently used in medicinal chemistry to access SAR around alkenyl/aryl motifs via cross-coupling, and to install triazole linkers through CuAAC in small-molecule or payload–linker synthesis.
  • The spiroacetal motif can modulate lipophilicity, conformational bias, and metabolic stability in lead optimization campaigns.

• Practical notes for R&D:

  • When generating libraries, record residual metal content after Pd/Cu-catalyzed steps to meet internal discovery thresholds.
  • Assess chemical stability in formulation-relevant solvents; avoid acidic aqueous media to prevent acetal hydrolysis unless deprotection is desired.

No claims are made regarding safety or efficacy in humans or animals. Not for use in diagnostic, therapeutic, or clinical applications.

Physical Properties

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

• Literature/general expectations for this class (for planning only; not product specifications):

  • Physical state: low-molecular-weight spiroacetals with terminal alkynes are commonly colorless liquids or low-melting solids; volatility can be moderate due to compact structure.
  • Boiling point & vapor pressure: small aliphatic acetals often boil in the 120–190 °C range at ambient pressure; ring strain and acetal functionality can reduce boiling point relative to linear ethers (literature/generic trends).
  • Density & refractive index: ethers typically display densities ~0.85–1.00 g/mL and nD 1.39–1.44 (literature ranges for dialkyl/acetal ethers).
  • Solubility: expected to be miscible with common organic solvents (Et2O, MTBE, THF, DCM, toluene, EtOAc) and sparingly soluble in water due to nonpolar backbone and acetal protection (literature trend for small acetals). Terminal alkynes dissolve well in moderately polar aprotic media (DMF, DMSO, MeCN) when needed.
  • pKa (C–H of terminal alkyne): typically ~25 (in DMSO, literature) for generic terminal alkynes; enables deprotonation with strong bases (e.g., NaNH2, LDA, n-BuLi) under anhydrous conditions.
  • Partitioning: logP for small acetals tends to be moderate (literature: ~1–2.5), supporting phase-transfer and extraction behavior in organic media.

Always rely on the SDS and the CoA for authoritative physical constants and handling parameters for this specific SKU.

Quality and Grades

• Item-specific grade/purity, stabilizers, metal limits, residual solvents, and chromatographic suitability: Not specified for this item; refer to CoA/Spec Sheet.

• How to interpret common grades (context for planning only):

  • Analytical/Reagent (AR) grade: suitable for most synthetic operations; impurities controlled to typical analytical standards.
  • HPLC grade solvents/reagents: low UV absorbance and particulates; used when optical or trace analyses are sensitive to background.
  • Anhydrous grade: moisture content tightly controlled; supplied in moisture-barrier packaging. Particularly beneficial if forming alkynyl metal acetylides or performing water-sensitive transformations.

• Spiroacetal with terminal alkyne—quality considerations (general):

  • Metal content: if using in cross-coupling or photoredox, trace metal background may influence catalysis; verify with CoA when critical.
  • Unsaturation integrity: monitor for oxidative dimerization or addition by GC/LC; minimize copper exposure and store tightly sealed.
  • Water: acetals are acid-labile; residual mineral acids from synthesis can promote hydrolysis. Confirm neutrality and absence of acid by specification/CoA when necessary.

For this catalog item, consult the lot-specific CoA for assay (%), major impurity profile, and any stabilizers or inhibitors. Where optical or trace analyses are involved, pre-qualify by a small trial run.

Reaction and Applications

The defining reactivity of 2‑Ethynyl‑5,8‑dioxaspiro(3.4)octane derives from its terminal alkyne juxtaposed with an acetal-protected spiro framework. This combination enables robust C–C bond formations while maintaining oxygenated functionality for later unmasking.

• Representative transformations (general literature guidance):

  • CuAAC (Huisgen cycloaddition): terminal alkyne reacts with organic azides to form 1,4‑disubstituted 1,2,3‑triazoles under Cu(I) catalysis. Useful for bioconjugation or linker installation when the spiroacetal serves as a conformational element.
  • Sonogashira coupling: Pd/Cu-cocatalyzed coupling with aryl/vinyl halides to append aromatic fragments; copper-free variants minimize Glaser side reactions. The acetal core typically tolerates these conditions if neutral to mildly basic.
  • Nucleophilic metalation: strong bases (NaNH2, n‑BuLi, LDA) generate the alkynyl anion for addition to electrophiles (aldehydes, epoxides, carbonyls), enabling chain extension with stereocontrol dictated by subsequent steps.
  • Hydroboration–oxidation / haloboration: furnishes vinyl boronates/halides for downstream Suzuki/Negishi couplings; regiochemistry controllable by catalyst/borane choice.
  • Selective hydrogenation: Lindlar or P‑2 Ni to the Z‑alkene; dissolving metal conditions (Birch-type) to E‑alkene—acetal remains intact under neutral conditions.
  • Electrophilic additions: HX, X2 additions across C≡C enable vinyl halide synthesis.
  • Late-stage deprotection: under aqueous acid, the spiroacetal can unmask to the corresponding carbonyl/diol motif, providing a handle for diversification.

• Practical notes:

  • Exclude oxygen/copper salts to suppress Glaser oxidative dimerization.
  • Keep conditions near-neutral when possible to protect the acetal; avoid strong aqueous acid/base unless strategically used.
  • Dry solvents and inert atmosphere improve yields in metalation and coupling chemistry.

Reaction Conditions

The following conditions reflect common literature practices for terminal alkynes and acetal-bearing substrates; they are provided as general guidance and are not product specifications.

• CuAAC (azide–alkyne cycloaddition):

  • Catalyst: CuSO4·5H2O (1–5 mol%) + sodium ascorbate (5–10 mol%) to generate Cu(I) in situ; or preformed Cu(I) sources (CuI, 1–5 mol%).
  • Solvent: t‑BuOH/H2O (1:1) or MeOH/H2O mixtures; 0.1–0.5 M.
  • Temp/Time: rt to 50 °C, 1–12 h; typically high conversions.
  • Notes: Deaerate to limit Glaser dimerization; include ligand (TBTA/THPTA) for sensitive systems.

• Sonogashira coupling:

  • Catalyst: Pd(PPh3)2Cl2 (1–3 mol%) with CuI (1–5 mol%) and base (iPr2NH, Et3N) in DMF/THF/MeCN; or copper-free protocols (Pd2(dba)3 + XPhos/SPhos).
  • Temp/Time: 25–80 °C, 1–24 h depending on aryl halide reactivity.
  • Notes: Oxygen exclusion critical; copper-free reduces oxidative dimerization.

• Alkyne metalation/addition:

  • Base: n‑BuLi or LDA (1.1–1.3 eq) in dry THF or toluene at −78 to 0 °C; quench with electrophile (R–X, carbonyls).
  • Notes: Ensure rigorously dry conditions; acetal is typically stable to these bases at low temperature but avoid prolonged warm exposure.

• Semihydrogenation:

  • Catalyst: Lindlar (Pd/CaCO3, Pb-poisoned) or NiBoride; H2 (1 atm) in EtOAc/MeOH/DCM at 0–25 °C to form Z‑alkene.

Verify compatibility with the specific substrate and consult primary literature before scale-up.

Safety and Handling

• Item-specific hazard classification (GHS, pictograms, H-statements, signal word): Not specified for this item; refer to SDS.

• General safety considerations for terminal alkyne spiroacetals (informational; not product-specific):

  • Flammability: small ethers/acetals and alkynes are typically flammable. Keep away from ignition sources and use in a fume hood with proper grounding during solvent transfers.
  • Reactivity: terminal alkynes can undergo oxidative coupling (Glaser-type) in the presence of Cu salts and O2; avoid unintended exposure to copper/air during storage and workup if monomer integrity is critical.
  • Acid sensitivity: acetals can hydrolyze under strong acidic aqueous conditions to the corresponding carbonyls/diols. Avoid strong acids and prolonged aqueous acidic workups.
  • Peroxide formation: acetals/ethers may form peroxides upon long air exposure; periodic testing is prudent for long-stored opened containers (general ether precaution—consult SDS before testing).
  • PPE: lab coat, nitrile gloves (change regularly), splash goggles. Use a certified chemical fume hood.
  • Incompatibilities: strong acids (hydrolysis), strong bases only when intentionally used (otherwise avoid to prevent deprotonation at C≡CH), oxidizing agents, copper/transition-metal salts if undesired coupling is a risk.
  • First aid (overview): in case of skin/eye contact, rinse with water for at least 15 minutes; if inhaled, move to fresh air; if ingested, seek medical attention. Always follow your institution’s SOPs.

Defer to the item’s Safety Data Sheet (SDS) for definitive hazards, exposure limits, and emergency measures.

Solvent Selection

This molecule behaves as a moderately nonpolar, aprotic organic building block with an ether-rich spiroacetal core and a terminal alkyne. It exhibits high solubility in common organic media and low solubility in water (general trends for small acetals/alkynes; not product-specific).

• Polarity/miscibility (literature/general):

  • Good solvents: DCM, chloroform, toluene, EtOAc, MTBE, diethyl ether, THF/2‑MeTHF, acetone, MeCN, DMF, DMSO.
  • Poor solvents: water and highly protic aqueous media (risk of acetal hydrolysis under acidic conditions).

• Selection by task:

  • Metalation (forming acetylides): use rigorously dry ethers (THF, 2‑MeTHF, TBME) or hydrocarbons (toluene/hexanes) with strong bases; maintain inert atmosphere.
  • Cross-couplings (Sonogashira-type): polar aprotic solvents (DMF, DMAc, NMP) or amine co-solvents (iPr2NH) facilitate catalyst solubility; oxygen exclusion critical to suppress Glaser dimerization.
  • Cycloadditions (azide–alkyne): MeOH/H2O or t‑BuOH/H2O mixtures often used under CuAAC; for copper-free SPAAC analogs this is not applicable, but standard CuAAC conditions apply to terminal alkynes.
  • Oxidations/reductions on alkyne: choose EtOAc, MeOH, or acetic acid for syn-dihydroxylation/Markovnikov additions (depending on method), or MeOH/DCM for hydroboration–oxidation cascades.

• Comparison (general):

  • THF vs 2‑MeTHF: 2‑MeTHF offers greener profile and higher hydrophobicity, aiding phase separation while supporting bases and organometallics similarly.
  • DCM vs toluene: DCM offers faster dissolution and lower bp; toluene is halogen-free and better aligned with green chemistry goals.

Storage and Reconstitution

• Item-specific storage: Room temperature (per Product Data). Shipped-in conditions: Not specified for this item; refer to CoA/Spec Sheet.

• General storage guidance for terminal alkynes and acetals (not product-specific):

  • Store in a tightly sealed, inert-compatible container. If long-term storage is anticipated, consider an inert gas headspace (N2/Ar) to minimize oxidative processes and inadvertent Glaser coupling in the presence of trace copper.
  • Protect from strong acids and excess moisture to prevent acetal hydrolysis. Avoid copper contamination.
  • Keep away from heat/ignition sources; segregate from oxidizers.

• Reconstitution/handling:

  • Product is typically used neat or as a solution in organic solvents (e.g., DCM, THF, EtOAc, MeCN). Dry solvents are recommended for base- or metal-sensitive steps.
  • Before critical reactions, consider passing through a short plug of basic alumina/silica or pre-rinsing containers to remove adventitious metal contaminants (general precaution for alkyne chemistry).

• Stability checks:

  • Monitor by GC/LC for signs of dimerization or hydrolysis upon prolonged storage after opening.

Follow the lot-specific CoA for any additional storage notes. For research use only.

Structure and Identity

Brief description: 2‑Ethynyl‑5,8‑dioxaspiro(3.4)octane is a compact spiroacetal bearing a terminal alkyne substituent. The scaffold features a spiro-junction between two small oxygen-containing rings and provides an aliphatic, nonconjugated environment for an sp-hybridized C≡C handle.

• Item-specific identifiers (from Product Data):

  • Product Name: 2-Ethynyl-5,8-dioxaspiro(3.4)octane
  • CAS: 1392803-25-6
  • CID: 72208254
  • InChIKey: 385274 (as provided)
  • SMILES: 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.

• Structural features (general/interpretive):

  • Functional groups: terminal alkyne (–C≡CH), two acetal ether oxygens within a spiro-fused bicyclic framework.
  • Ring system: a spiro(3.4)octane core indicates two rings (one 4‑membered, one 5‑membered) sharing a quaternary spiro center; the “5,8‑dioxaspiro” descriptor signifies two oxygens embedded in the rings (spiroacetal).
  • Stereochemistry: no stereogenic centers are implied by the name besides the spiro center (which is not stereogenic in a symmetric context); overall likely achiral unless ring substitution breaks symmetry (literature/generic interpretation).
  • 2D description: a central spiro carbon joins an oxetane-like ring and a 1,3‑dioxolane-like ring (generic depiction) with an ethynyl group at the 2‑position relative to the acetal context.

Notes: Exact atom connectivity, stereochemical descriptors, SMILES, and empirical formula for this SKU are not specified in the provided data and should be confirmed from the Certificate of Analysis (CoA) or structure file supplied with the lot.

Synthetic Utility

2‑Ethynyl‑5,8‑dioxaspiro(3.4)octane offers a compact, oxygenated scaffold with a versatile terminal alkyne—ideal for diversification without introducing additional heteroatom basicity.

• Strategic roles (general literature guidance):

  • Alkyne as a linchpin:
    • Couple (Sonogashira) to aryl/vinyl halides to append pharmacophores, followed by selective semihydrogenation to Z‑alkenes.
    • Convert to vinyl boronates/halides (hydroboration/haloboration), then apply Suzuki/Negishi couplings, enabling modular fragment growth.
    • Perform alkynylation of electrophiles via metal acetylides to forge propargylic alcohols and allene/vinyl derivatives by rearrangement.
  • Bioorthogonal gateway: CuAAC to install triazoles that can act as robust amide bioisosteres; useful in linker chemistry for materials and probe design.
  • Protected functionality: The spiroacetal masks underlying carbonyl/polyol functionality; selective acidic deprotection late in a sequence unpacks additional handles for derivatization.

• Orthogonality and stability:

  • The acetal typically withstands neutral to mildly basic conditions (Pd-catalysis, organoboron chemistry), expanding the reaction window around the alkyne.
  • Avoid prolonged exposure to strong Brønsted acids or Lewis acids that target acetal cleavage unless that is the synthetic intent.

• Downstream elaborations:

  • Gold-catalyzed or Brønsted acid-mediated intramolecular hydrofunctionalizations of alkynes (where applicable) can build additional ring strain/complexity.
  • Radical additions (photoredox) across C≡C furnish difunctionalized products under mild conditions.

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, species reactivity, or isotype information applies.