4-tributylstannylpyridine - Reagent grade

Cat. No.: T481559

GRADE & PURITY Reagent Grade

Storage

Room temperature

Specifications

Specifiche e purezza

Reagent grade

Condizioni di conservazione di stoccaggio

Room temperature

Grado

Reagent Grade

Application Protocols

Not applicable. No bioassay or immunoassay protocols (WB, IHC, IF, FC) are associated with this small-molecule reagent. For practical laboratory use, see Reaction Conditions and Application notes in Reaction & Applications.

Biological Roles

This product is a synthetic organic reagent for laboratory use and does not have a native biological role.

• General context (literature; not item-specific)
  • Pyridine is a core heteroaromatic motif found in numerous bioactive molecules and in biological cofactors by analogy to nicotinamide (NAD+/NADP+ systems), but 4‑tributylstannylpyridine itself is not endogenous.
  • Organotin compounds are not biogenic and can be toxic to organisms; avoid environmental release.

Research Use Note: For research use only (per Product Data). No clinical or in vivo use is implied or supported.

Buffer Applications

Not typically applicable. 4‑Tributylstannylpyridine is a hydrophobic organometallic reagent and is not used as a buffering agent or in aqueous buffer preparation. For this material’s practical use, see Reaction & Applications, Synthetic Utility, and Reaction Conditions.

Green Alternatives

Organostannane chemistry is effective but raises EHS concerns (organotin toxicity, persistent tin residues). Consider greener cross-coupling partners when feasible.

• Greener surrogates (literature/general)

  • Organoboron (Suzuki–Miyaura): use 4-borylpyridine or boronate esters. Advantages: low toxicity, aqueous workups; Disadvantages: some heteroaryl couplings are slower or require base-sensitive conditions.
  • Organosilicon (Hiyama/Denmark): 4‑(trialkoxysilyl)pyridines activated by fluoride. Advantages: benign byproducts; Disadvantages: need fluoride promoters, sometimes higher temperatures.
  • Organozinc (Negishi): 4‑pyridylzinc halides. Advantages: highly reactive; Disadvantages: air/moisture sensitivity, pyrophoric handling.

• Comparative considerations

  • Waste profile: Sn >> Zn > Si ≈ B in environmental burden; tin-containing waste often requires specialized disposal.
  • Functional group tolerance: Stille generally excels with sensitive heterocycles; Suzuki/Hiyama may need tuning of base/ligand.
  • Operational simplicity: Boron reagents are typically easiest to handle and purify; silicon next; zinc and tin require more careful waste management.

• Practical pathway planning

  • If a boron analog is commercially available (e.g., 4‑(pinacolboronyl)pyridine), attempt Suzuki first. Reserve the stannane for cases where boron fails (e.g., deactivated aryl chlorides, problematic heterocycles) or where halodestannylation is strategically required.

Note: Selection should balance EHS impact, yield/selectivity, scalability, and downstream purification constraints.

Pharmaceutical Uses

No excipient or formulation role is indicated for this product. It is used in discovery and process chemistry as a heteroaryl coupling partner or intermediate.

• Research/manufacturing context (literature/general)
  • Employed to build 4‑pyridyl linkages in API intermediates via Stille coupling when other methods are ineffective.
  • Halodestannylation provides 4‑iodopyridines as versatile hubs for subsequent functionalization (e.g., metal–halogen exchange, cross-coupling).

Regulatory note: Organotin residues are regulated in pharmaceutical manufacturing; processes employing stannanes typically include rigorous tin scavenging and specification testing. This product is for research use only.

Physical Properties

Item-specific physical constants are not provided in the Product Data.

• Item-specific values

  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.
  • Density, refractive index, melting/boiling point, UV cutoff, water/peroxide/metal content: Not specified for this item; refer to CoA/Spec Sheet.

• Literature/general properties for aryl-tributylstannanes (for orientation only; not item specifications)

  • Physical state: typically colorless to pale yellow liquids or low-melting solids, with high boiling points owing to the heavy Sn center and three alkyl chains.
  • Solubility: highly soluble in nonpolar and moderately polar aprotic organic solvents (e.g., hexanes, toluene, CH2Cl2, THF); essentially insoluble in water.
  • Polarity: overall hydrophobic; negligible hydrogen-bonding capability; donor number ~0 (no strong Lewis basic sites beyond the pyridine N, which is deactivated by conjugation and steric environment).
  • Stability: generally air- and moisture-stable under ambient conditions; can slowly oxidize at the tin center on prolonged air exposure or under strong oxidizing conditions.
  • Typical logP: high (reflecting three n-butyl chains); exact value depends on substitution pattern.

Always consult the SDS and the CoA/Spec Sheet for authoritative, lot-specific physical data before process design or safety assessments.

Quality and Grades

• Grade for this item: Reagent Grade (per Product Data)

  • Meaning: Suitable for general laboratory synthesis and routine research applications. Reagent Grade materials typically meet broadly accepted purity criteria for bench chemistry but are not optimized for trace analysis, LC/GC, or bio/pharma GMP uses unless otherwise stated.

• What is not specified for this item

  • Exact assay/purity %, residual solvents, metal/content limits, water/peroxide ppm, stabilizers, UV cutoffs: Not specified for this item; refer to CoA/Spec Sheet.

• Practical implications for use

  • For Pd-catalyzed cross-couplings (e.g., Stille), Reagent Grade 4-tributylstannylpyridine is commonly acceptable. If performing sensitive catalysis or analytical applications, consider pre-purification (e.g., short silica plug under neutral conditions) and verify by 1H/13C/119Sn NMR.
  • If very low UV background is required (e.g., detector baselines), HPLC-grade solvents and additional purification of the reagent may be necessary since Reagent Grade does not guarantee low UV absorbance of trace impurities.

• Documentation

  • For batch-specific details (assay, residual halides, limits on tin oxides), consult the CoA/Spec Sheet. These govern acceptance criteria and should be referenced in SOPs and batch records where applicable.

Reaction and Applications

4-Tributylstannylpyridine is a versatile nucleophilic heteroaryl donor used primarily in palladium-catalyzed cross-coupling and in electrophilic substitution at tin.

• Key reaction families (literature/general)

  • Stille coupling (Pd-catalyzed C–C formation): couples the 4-pyridyl unit to aryl, vinyl, and certain acyl electrophiles (iodides, bromides, triflates, and activated chlorides). Heteroaryl–heteroaryl linkages are a hallmark application where organoboron partners can be less effective.
  • Halodestannylation: rapid conversion to 4-halo derivatives (e.g., 4-iodopyridine) using I2, NIS/NBS, or Cl2 under mild conditions—useful for installing a versatile handle or for radioiodination precursor preparation.
  • Tin–boron exchange: preparation of 4-borylpyridines (e.g., via BCl3 or B2pin2 in the presence of copper/halide promoters), enabling subsequent Suzuki couplings.
  • Protodestannylation: removal of SnBu3 to regenerate 4-H pyridine under acidic or radical conditions when deprotection is desired.
  • Radical reactions: under AIBN/initiator and suitable reagents, the stannyl group can participate in radical chains (less common for aryl stannanes than for Bu3SnH but conceptually related chemistry applies).

• Practical considerations

  • Catalyst systems: Pd2(dba)3/PPh3, Pd(PPh3)4, or PdCl2(dppf)·DCM are typical for Stille; bulky electron-rich ligands (e.g., P(tBu)3) can accelerate challenging couplings.
  • Order of addition: pre-activate Pd with the electrophile, then introduce the stannane to minimize homocoupling; degas to suppress catalyst deactivation.
  • Workup: include KF or aqueous fluoride wash only if needed to break tin emulsions; otherwise, silica filtration with scavengers (e.g., Si-TMT, thiol or mercaptopropyl silica) helps remove residual tin.

Applications span synthesis of heteroaryl scaffolds, ligands, OLED materials, and advanced intermediates in agro/medchem discovery (research use only).

Reaction Conditions

The following are literature/general conditions for transformations of 4‑tributylstannylpyridine (guidance only; optimize experimentally). Item-specific specifications are not provided.

• Stille coupling (C–C)

  • Catalyst: 1–5 mol% Pd(PPh3)4 or 2–3 mol% Pd2(dba)3 with 4–12 mol% PPh3, P(o‑Tol)3, or P(tBu)3.
  • Electrophiles: aryl/vinyl iodides, bromides, triflates; activated chlorides with appropriate ligands.
  • Solvent: toluene, 1,4‑dioxane, THF, or DMF; degassed.
  • Temperature/time: 60–120 °C, 2–24 h depending on substrate.
  • Additives: CuI (5–20 mol%) can accelerate difficult heteroaryl couplings; LiCl sometimes beneficial. Base often not required.
  • Workup: concentrate, pass through silica/Scavenger resin to remove tin; aqueous washes with brine; optional KF wash to disrupt emulsions.

• Iododestannylation (to 4‑iodopyridine)

  • Reagents: I2 (1.05–1.5 equiv) in CH2Cl2 or MeCN; 0 °C to rt, 0.5–2 h.
  • Quench: Na2S2O3 to destroy residual iodine; avoid excess oxidant to limit over-iodination elsewhere.

• Tin–boron exchange

  • Reagents: BCl3 (1–2 equiv) in CH2Cl2 at −78 to 0 °C, then quench with pinacol/Et3N; or Pd/Cu‑mediated exchange with B2pin2 in THF/toluene (60–90 °C).

• Protodestannylation

  • Conditions: TFA or AcOH under reflux; or radical H‑atom conditions (AIBN/HSnBu3 analogs) if compatible.

Expected yields: Commonly 60–90% for optimized Stille couplings with heteroaryl partners; halodestannylations often >80%. Actual results depend on substrate/catalyst system.

Safety and Handling

• Item-specific hazard classification

  • Signal word, H-statements, GHS class, pictograms: Not specified for this item; refer to SDS.

• General hazards of organotin compounds (literature; not item-specific)

  • Organotin species can exhibit acute and chronic toxicity; certain tributyl compounds are known aquatic toxins. Avoid environmental release. Handle with care to minimize skin contact and inhalation of vapors/aerosols.
  • Aryl-tributylstannanes are typically less volatile and less acutely toxic than tributyltin halides, but prudent handling as a potentially toxic organometallic is essential.

• PPE and engineering controls

  • Use in a fume hood. Wear lab coat, safety glasses or face shield, and appropriate chemical-resistant gloves (e.g., nitrile). For larger scale, consider double-gloving and splash protection.
  • Avoid heating to decomposition; use inert atmosphere when scaling high-temperature couplings to limit oxidative byproducts of tin.

• Incompatibilities and reactivity

  • Strong oxidizers (risk of exothermic oxidation at Sn); electrophilic halogen sources (I2, NBS, NIS) can rapidly halodestannylate; strong acids may promote cleavage to more toxic tin species.
  • Avoid contact with silica impregnated with strong acids/bases if not intended—can promote protodestannylation.

• First aid (overview; defer to SDS)

  • Skin: Wash with soap and water; remove contaminated clothing.
  • Eyes: Rinse cautiously with water for several minutes; seek medical attention.
  • Inhalation: Move to fresh air; seek medical advice if symptoms occur.
  • Ingestion: Rinse mouth; seek medical attention.

Waste: Capture tin-containing wastes separately; dispose as hazardous waste per institutional and regulatory guidance (organotin residues are regulated in many jurisdictions).

Solvent Selection

This product is a hydrophobic organometallic reagent rather than a solvent. Selection here refers to reaction media for its use.

• Solubility/miscibility profile (literature/general)

  • Readily soluble: nonpolar and moderately polar aprotic solvents (hexanes/heptane, toluene, xylene, CH2Cl2, CHCl3, THF, MTBE, CPME, DMF).
  • Poorly soluble: alcohols and water.

• Media choice by transformation

  • Stille couplings: toluene, dioxane, DMF, or mixed toluene/DMF; sometimes THF. Choice balances solubility of the electrophile and catalyst stability.
  • Iododestannylation/halodestannylation: CH2Cl2, MeCN, or Et2O at 0 °C to rt to moderate exotherm and control selectivity.
  • Tin–boron or tin–silicon exchange: THF, toluene, or CH2Cl2 depending on electrophile (e.g., BCl3 vs B2pin2 systems).

• Practical tips

  • Include a base scavenger only when required by the electrophile; unnecessary base can induce protodestannylation.
  • Moisture usually has limited impact on the stannane itself, but can deactivate catalysts and quench sensitive electrophiles—use dry, degassed solvents for cross-coupling.

• Comparison (general)

  • vs. organoboron analogs: Stille can be more tolerant of acidic functional groups and water, but organotin waste is more problematic; Suzuki is greener but can be less effective for some heteroaryl couplings.

Storage and Reconstitution

• Storage (per Product Data)

  • Store at room temperature.

• Additional handling guidance (general best practice)

  • Keep container tightly closed under inert gas if possible to minimize slow oxidation at tin and moisture ingress into solvents present in the bottle.
  • Protect from strong oxidizers and halogenating agents during storage. Avoid prolonged exposure to air and light if not necessary.
  • If solids precipitate on cold storage, allow to warm to ambient and mix thoroughly before use; analyze by NMR to confirm integrity if in doubt.

• Reconstitution: Not applicable—supplied as a neat reagent. If dilution is needed for dosing, prepare stock solutions in dry, oxygen-free solvents (e.g., toluene, CH2Cl2, or THF) and store short-term at 2–8 °C under inert gas.

• Shipping: Not specified for this item; refer to CoA/Spec Sheet and SDS.

• Shelf life: Not specified for this item; verify by routine QC (e.g., 1H/13C/119Sn NMR, TLC/GC) before use in critical experiments.

Structure and Identity

A para-stannylated heteroaromatic building block combining a pyridine ring with a tributylstannyl group at the 4-position (para to the ring nitrogen).

• Item-specific identifiers
  • CAS: Not specified for this item; refer to CoA/Spec Sheet.
  • InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
• Literature/computed identity (for general reference; not an item specification)
  • Preferred name: 4-tributylstannylpyridine (para-tributylstannylpyridine)
  • Molecular formula (computed): C17H31NSn
  • Molecular weight (computed): ~367.9 g/mol
  • Structural features: one six-membered aromatic pyridine ring (sp2 C5N) bearing a single C–SnBu3 substituent at C-4; tin(IV) bound to three n-butyl chains and the aryl carbon (tetraorganotin center).
  • 2D description: pyridine ring with N at position 1; at position 4 (para), a carbon–tin bond connects to a Sn center carrying three linear n-butyl groups.
• Stereochemistry: No stereogenic centers; tin center is tetra-coordinate without a defined stereochemical descriptor under typical representations.

Notes: The above general identity details are based on the named structure; verify exact identifiers for this SKU on the CoA/Spec Sheet before reporting or using in regulated contexts.

Synthetic Utility

Functional groups and reactivity profile make 4‑tributylstannylpyridine a powerful, directed 4‑pyridyl synthon.

• Functional handles

  • Aryl–SnBu3: nucleophilic partner in Pd-catalyzed C–C bond formation (Stille). Undergoes electrophilic substitution at tin (iodo-, bromo-destannylation) and transmetalation to B, Si, or Cu.
  • Ring nitrogen: coordinates to metals/acids; can modulate catalyst speciation in couplings (occasionally beneficial in directing reactivity).

• Transformations enabled (literature/general)

  • C(sp2)–C(sp2)/C(sp2)–C(sp) couplings with aryl/vinyl/alkynyl halides or triflates.
  • Synthesis of 4‑halo-, 4‑boryl-, 4‑silyl‑, or 4‑alkyl/aryl‑pyridines via appropriate electrophiles and conditions.
  • Late-stage heteroaryl installation onto complex electrophiles (tolerant of esters, amides, nitriles, and certain protected amines/phenols).

• Retrosynthetic value

  • Converts difficult electrophiles into 4‑pyridyl products with high regioselectivity (para relative to N), circumventing issues of directed metalation on pyridines.

• Downstream processing

  • Tin removal strategies: scavenger resins (thiol- or dithiocarbamate-functionalized silica), precipitation as SnS with Na2S, or extraction with EDTA-containing aqueous phases (check compatibility). Residual Sn analysis by ICP‑OES/ICP‑MS.

Overall: A reliable, high-yielding entry to 4‑pyridyl motifs when greener partners underperform, with well-understood workup/purification techniques to manage tin.

Target Specificity

Not applicable. This product is a small-molecule chemical reagent, not a biological affinity reagent or antibody. No antigen/epitope/clone/isotype information applies.