Pyridine - 1000μg/ml,in Purge and Trap Methanol , CAS No.110-86-1

CAS: 110-86-1 Cat. No.: P141189 Fórmula: C₅H₅N Peso molecular: 79.1 Beilstein Registry Number: 103233 Número CE: 203-809-9

GRADE & PURITY 1000μg/ml,in Purge and Trap Methanol

Synonyms

Azabenzene

Storage

Room temperature

Shipped In

FedEx DG Service

Specifications

Sinónimos

Azabenzene

Especificações e pureza

1000μg/ml,in Purge and Trap Methanol

Condições de armazenamento de armazenamento

Room temperature

Enviado em

FedEx DG Service

Nomes e identificadores

InChIKey

JUJWROOIHBZHMG-UHFFFAOYSA-N

INCHI

1S/C5H5N/c1-2-4-6-5-3-1/h1-5H

SMILES isoméricas

C1=CC=NC=C1

WGK Alemanha

2

RTECS

UR8400000

Número UN

1282

Grupo de embalagem

II

Peso molecular

79.1

Beilstein

103233

Reaxy-Rn

103233

Reaxys-RN_link_address

https://www.reaxys.com/reaxys/secured/hopinto.do?context=S&query=IDE.XRN=103233&ln=

Taxonomic Classification

Taxonomy Tree

• Kingdom Organic compounds
  • Superclass Organoheterocyclic compounds
    • Classe Pyridines and derivatives

• Kingdom: Organic compounds
• Superclass: Organoheterocyclic compounds
• Classe: Pyridines and derivatives
• Subclass: Not available
• Intermediate Tree Nodes: Not available
• Direct Parent: Pyridines and derivatives
• Alternative Parents: Heteroaromatic compounds Azacyclic compounds Organopnictogen compounds Organonitrogen compounds Hydrocarbon derivatives
• Molecular Framework: Aromatic heteromonocyclic compounds
• Substituents: Pyridine - Heteroaromatic compound - Azacycle - Organic nitrogen compound - Organopnictogen compound - Hydrocarbon derivative - Organonitrogen compound - Aromatic heteromonocyclic compound
• Descrição: This compound belongs to the class of organic compounds known as pyridines and derivatives. These are compounds containing a pyridine ring, which is a six-member aromatic heterocycle which consists of one nitrogen atom and five carbon atoms.
• External Descriptors: a ring

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

Alvos associados (humanos)

NAPRT Tchem Nicotinate phosphoribosyltransferase (2 Activities)

Discover Target: NAPRT

Activity Type	Activity Value -log(M)	Mechanism of Action	Activity Reference	Publications (PubMed IDs)

Propriedades químicas e físicas

• Índice de refração: 1.5092
• Ponto de inflamação (°F): 68.0 °F - closed cup
• Ponto de inflamação (°C): 20 °C - closed cup
• Ponto de ebulição (°C): 115°C
• Ponto de fusão (°C): -42°C

Application Protocols

No assay-specific protocols (e.g., WB, IHC, IF, FC) are applicable to neat pyridine. For synthetic uses, see the Reaction & Applications and Reaction Conditions sections for practical guidance. Always consult lab SOPs and the SDS when incorporating pyridine into procedures.

Biological Roles

Scope note: This product is intended for research use only. The following discusses the pyridine ring system in biochemistry; it does not imply biological or clinical use of neat pyridine.

General biochemistry (literature):

• The pyridine nucleus is a core motif in essential cofactors nicotinamide adenine dinucleotide (NAD+/NADH) and NADP+/NADPH, mediating hydride transfer in redox enzymes across metabolism (glycolysis, TCA, fatty acid biosynthesis).
• Niacin (vitamin B3) is a substituted pyridine that serves as a precursor to NAD(P)+ in humans and microbes.
• Many natural products and alkaloids (e.g., nicotine) contain pyridine or dihydropyridine substructures, illustrating the ring’s prevalence in biosynthesis.
• Protonation state: In aqueous media near neutral pH, unsubstituted pyridine exists mostly as the free base (pKa of pyridinium ≈ 5.2). In cells, pendant pyridine rings in biomolecules can engage in acid–base and cation–π interactions.

Laboratory biology interfaces:

• As a neat chemical, pyridine is typically avoided in biological systems due to cytotoxicity and odor; however, it may be encountered as a residual solvent in extracts or as a leaving group in activated esters (pyridinium species) during bioconjugation chemistry.

Buffer Applications

Applicability: Neat pyridine is not a standard biological buffer. Its strong odor/toxicity and modest conjugate-acid pKa (~5.2, literature) limit routine buffering applications in biochemistry.

Specialized/literature uses (for reference only):

• Pyridine–acetic acid buffers have been used historically in electrophoresis and paper chromatography around pH ~5.0–6.5, leveraging the pyridinium/pyridine conjugate pair. Due to odor, volatility, and safety concerns, they are largely supplanted by acetate, MES, or phosphate systems.
• In analytical chemistry, pyridine-containing media can modulate basicity for derivatizations (e.g., acylations of amines) rather than serve as true buffers.

Recommendation:

• For buffering near pH 5–6, prefer acetic acid/acetate, MES, or citrate buffers. Reserve pyridine-containing systems for historical method replication with appropriate ventilation and safety controls.

Green Alternatives

Context: While pyridine is synthetically powerful, it is odorous, toxic, and a volatile organic compound. Where feasible, consider greener choices that reduce exposure and environmental impact without sacrificing performance.

Potential alternatives (literature comparison):

• 2,6-Lutidine (xylylidine): Less nucleophilic, higher bp, reduced volatility and odor; similar basicity. Tradeoff: poorer water miscibility; costlier.
• Triethylamine (TEA) or DIPEA: Commonly used non-nucleophilic bases with lower odor; easy to remove (volatile TEA). Tradeoff: not suitable as primary solvent in some polar transformations; weaker coordination.
• N-Methylimidazole (NMI): Stronger nucleophilic catalyst/base with lower odor than pyridine; excellent for acylations/sulfonylations. Tradeoff: more persistent in aqueous waste; potential ecotoxicity concerns.
• 2-MeTHF or CPME as solvent: Greener, biorenewable ethers with good solvency; pair with an external base (TEA/DIPEA). Tradeoff: immiscible with water; peroxide management for ethers.
• Water/ethanol media with enzyme or organocatalysis: In specific acylations or condensations, biocatalysts can replace pyridine-based systems. Tradeoff: narrower substrate scope; process redevelopment required.

Compact comparison (general, not item-specific):

• Metric highlights: lower VOC emissions (2-MeTHF vs pyridine), improved worker exposure profile (TEA/DIPEA vs pyridine), and reduced persistent odor in facilities.

Practical approach:

• Map the role of pyridine (solvent vs base vs ligand) and substitute role-by-role; pilot substitutions at small scale to evaluate rate/selectivity, odor control, and waste profile.

Pharmaceutical Uses

Scope: No therapeutic claims. This section addresses manufacturing/formulation context only.

General pharmaceutical relevance (literature):

• Process solvent/base: Pyridine is widely employed in API process chemistry for acylations, sulfonylations, halogenations (e.g., with SOCl2/POCl3), and as a ligand. Selection is driven by performance; odor/toxicity necessitate robust containment.
• Residual solvent regulation: Under ICH Q3C, pyridine is a Class 2 solvent with a permitted daily exposure (PDE) of 2.0 mg/day and a concentration limit of 200 ppm in drug products. Analytical controls (GC headspace) are standard when pyridine is used upstream.
• Excipients: Pyridine itself is not used as a pharmaceutical excipient due to toxicity and odor.
• Formation of reagents: Generation of pyridinium-based reagents (e.g., PCC, PDC) for selective oxidations in GMP routes requires dedicated controls for chromium residues and worker safety.

Practical considerations:

• Equipment: Employ closed systems with vapor recovery and activated carbon scrubbing to manage odor and VOC emissions.
• Cleaning validation: Given its low odor threshold, olfactory detection can be sensitive; quantitative rinse sampling with GC is recommended.
• Waste handling: Aqueous waste streams containing pyridine should be segregated; consider steam stripping or carbon adsorption prior to biological treatment.

Physical Properties

Item-specific physical specifications (this lot):

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Any numeric specifications (bp, mp, density, water, metals, UV cutoff, stabilizers): Not specified for this item; refer to CoA/Spec Sheet.

Literature/reference properties for pyridine (for planning and method development; not product specifications):

• State/appearance (literature): colorless to pale yellow liquid with characteristic fishy/amine-like odor.
• Boiling point (literature): ~115–116 °C at 1 atm.
• Melting point (literature): ~−41 to −42 °C.
• Density (literature): ~0.981 g/mL at 20 °C.
• Refractive index (literature): n20/D ≈ 1.509.
• Vapor pressure (literature): ~20 mmHg at 25 °C (order of magnitude; varies by source).
• LogP (XlogP3, literature): ~0.65 (moderately polar, water-miscible).
• pKa (conjugate acid, literature): ~5.2 (pKb ~8.8 for the free base); basicity attenuated in nonpolar media.
• Solubility (literature): miscible with water and most organic solvents (EtOH, Et2O, acetone, MeCN, chlorinated solvents). Forms strong H-bonds as acceptor; protonated readily by mineral acids.

Practical notes (general):

• Drying: can be dried over KOH pellets or CaH2 followed by distillation; store over molecular sieves (3Å/4Å) for water-sensitive work.
• Odor threshold is low; use containment/ventilation to control fugitive vapors.

Quality and Grades

Item-specific quality information:

• Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet for assay, water, and impurity profile.
• Stabilizers/Inhibitors: Not specified for this item; refer to CoA/Spec Sheet.

Guidance on common pyridine grades (general information):

• ACS/Reagent Grade: Suitable for general analytical and synthetic work; assay typically ≥99%. Trace impurity limits (e.g., nonvolatile matter, acidity/alkalinity) controlled per ACS specifications.
• Anhydrous Grade: Dried to low water content (often ≤50–200 ppm by KF); intended for moisture-sensitive reactions (e.g., acid chloride acylations). Verify with CoA; dry further over CaH2 or molecular sieves if needed.
• HPLC Grade: Low UV absorbance background and low nonvolatile residue for chromatographic compatibility. Given pyridine’s strong UV absorption and odor, use judiciously in LC mobile phases; modern LC typically avoids pyridine in favor of less odorous bases.
• Spectrophotometric/UV Grade: Tight control of absorbance in the 190–400 nm range; used historically in UV methods.

Practical considerations:

• Trace water and low-boiling amines can influence base strength and reaction selectivity; confirm water/amine impurities by KF and GC where critical.
• Residual aldehydes/ketones can form Schiff bases; pre-treat with solid acid scavengers or distill if sensitive.
• Always defer to the item-specific CoA/SDS for definitive quality attributes, storage, and handling.

Reaction and Applications

Overview: Pyridine is widely used as a base, nucleophilicity-moderated solvent, and ligand. Its ability to scavenge strong acids (forming pyridinium salts) makes it a workhorse in acylation and sulfonylation chemistry.

Common applications (literature; practical notes included):

• Acylations with acyl chlorides/anhydrides: Serves as base and solvent; captures HCl to give pyridinium chloride, minimizing side reactions. Typical conditions: 0–25 °C, 1–4 equiv pyridine when used as base; catalytic DMAP often accelerates with substoichiometric pyridine as solvent or co-base.
• Tosylations/mesylations: Pyridine solubilizes sulfonyl chlorides and neutralizes HCl; 0–5 °C additions recommended to control exotherm.
• Activation with SOCl2/POCl3/oxalyl chloride: Added as base to moderate HCl release and to form reactive acylating species; gas evolution requires vented setup and low-temperature control.
• Formation of pyridinium reagents: PCC (pyridinium chlorochromate), PDC, and Collins reagent are generated from pyridine and Cr(VI) sources—handle with extreme care; prepare behind shields with proper PPE.
• N-oxidation and subsequent ring functionalization: Pyridine N-oxide enables electrophilic substitution at the 4-position followed by deoxygenation (e.g., via POCl3), underpinning synthesis of substituted pyridines.
• Ligand and base in metal-catalyzed reactions: Can coordinate to Pd, Cu, and others—sometimes beneficial (stabilization), sometimes inhibitory (catalyst poisoning); screen loadings accordingly.

Operational guidance:

• Drying: Distill from KOH or CaH2; store over 3–4 Å sieves.
• Workup: Remove by azeotropic codistillation with toluene/hexanes or acid-base extraction (convert to pyridinium salt then basify and strip). Odor control via closed transfers and cold traps.

Reaction Conditions

General guidance from literature and practice (not item-specific specifications):

• Acylations (acid chlorides/anhydrides):

  • Typical solvent/base: neat pyridine or co-solvent (DCM, toluene) with 1–3 equiv pyridine.
  • Temperature: 0–25 °C; exothermic on addition—cooling advised.
  • Workup: Quench with aqueous acid to protonate residual pyridine, separate layers, basify to recover product if needed.

• Sulfonylations (e.g., TsCl):

  • Base: 2–4 equiv pyridine; temperature 0–5 °C during addition, then 20–25 °C.
  • Catalysis: Addition of catalytic DMAP can accelerate reactions at lower pyridine loadings.

• Oxidation reagent preparation (PCC/PDC):

  • Formed by combining pyridine with Cr(VI) oxidants under cooled, controlled conditions; use dry solvents; strong oxidants demand shields and expert SOPs.

• Dehydrations/activations with POCl3/SOCl2:

  • Add electrophile to pyridine at 0 °C to control HCl evolution; subsequent reaction with substrate at 0–80 °C depending on transformation (e.g., amide → nitrile often 60–80 °C).

• Drying/conditioning of pyridine:

  • Dry over KOH pellets overnight, then distill; for rigor, polish over 3–4 Å sieves. Water content verification by Karl Fischer where critical.

• Catalyst compatibility:

  • Pyridine can poison Lewis acid and some transition-metal catalysts; evaluate with small-scale screens or replace with hindered bases if needed.

• Removal strategies:

  • Azeotrope with toluene/hexanes; convert to pyridinium salt for aqueous extraction; use vacuum stripping with chilled traps to mitigate odor.

Safety and Handling

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: Not specified for this item; refer to SDS.
• Pictograms: Not specified for this item; refer to SDS.
• Shipped in: FedEx DG Service (flammable/regulated, per Product Data).

Typical GHS classification for pyridine (literature; consult the SDS for this item as authoritative):

• Flammable liquid, Cat. 2 or 3 (flash point ~20 °C); GHS02 (flame).
• Acute toxicity (oral/dermal/inhalation) Cat. 4; Skin irritation Cat. 2; Eye irritation Cat. 2A; STOT SE Cat. 3 (respiratory irritation); Aquatic chronic Cat. 3. GHS07 (exclamation mark); some SDSs include GHS09.

Key hazards and precautions (general):

• Highly odorous, volatile base; causes irritation to eyes, skin, and respiratory tract; harmful if swallowed or inhaled. Use in a functioning fume hood.
• Keep away from heat, sparks, open flames, and hot surfaces. Ground/bond when transferring bulk quantities.
• Incompatibilities: strong oxidizers (risk of exotherm), strong acids (violent neutralization), acylating/sulfonylating agents (vigorous reaction), nitrosating agents. Can attack some plastics; prefer glass/compatible PTFE.
• PPE: lab coat, splash goggles, nitrile gloves (change regularly), and appropriate respirator if engineering controls are inadequate (per institutional policy/SDS).
• First aid (overview; follow SDS): move to fresh air if inhaled; rinse skin with water and remove contaminated clothing; flush eyes with water for ≥15 min; seek medical attention if symptoms persist; if ingested, rinse mouth—do not induce vomiting; get medical help.
• Spill response: absorb with inert material, contain vapors, and dispose per local regulations.

Solvent Selection

Applicability: Pyridine functions both as a polar, basic solvent and as a catalytic/stoichiometric base. Selection should weigh its strong odor/toxicity against unique performance in specific transformations.

General solvent profile (literature):

• Polarity/proticity: Polar aprotic; strong H-bond acceptor; Lewis basic.
• Dielectric constant: ~12.3 at 25 °C (moderate polarity).
• Miscibility: Miscible with water and most organics (alcohols, ethers, ketones, chlorinated solvents, aromatics).
• Coordinating ability: Coordinates to Lewis acids and metal centers, modulating reactivity and sometimes inhibiting catalysts.

When to choose pyridine:

• As base and nucleophilicity-suppressing medium for acylations/sulfonylations where concurrent HCl capture is required.
• For reactions benefiting from coordination to electrophiles (e.g., activating SOCl2/POCl3) or where basic solvents suppress side reactions.
• As a ligand/solvent in certain organometallic preparations and for forming pyridinium activation reagents in situ.

Alternatives to consider:

• Triethylamine, DIPEA, 2,6-lutidine (bases with lower odor and varied sterics) when solvent role is not required.
• Acetonitrile, DMF, DCM, 2-MeTHF as less odorous polar aprotic media depending on solubility and compatibility.

Comparison (general):

• Pyridine vs 2,6-lutidine: similar basicity; lutidine is less nucleophilic and less coordinating; higher bp, less volatile.
• Pyridine vs DMF: DMF less odorous, higher polarity, but more prone to decomposition at high T; DMF lacks gas capture capacity for HCl unless base is added.

Storage and Reconstitution

Item-specific storage from Product Data:

• Storage conditions: Room temperature.
• Shipped in: FedEx DG Service (regulated transport).

General storage guidance (literature/practice; not item-specific specs):

• Keep container tightly closed in a cool, well-ventilated area away from ignition sources. Use flame-proof cabinets for flammables where required.
• Protect from acids and oxidizers; segregate from reactive halogenating agents.
• Minimize headspace and consider nitrogen blanket for long-term storage to limit oxidative discoloration and vapor loss (optional).
• For water-sensitive applications, store over 3–4 Å molecular sieves or with a small amount of KOH pellets in a dedicated bottle; verify dryness by KF before critical work.
• Secondary containment recommended due to odor; use PTFE-lined caps to reduce permeation.

Reconstitution: Not applicable—supplied neat as a liquid. If solidification occurs under cold conditions (unlikely; mp ~−41 °C), warm gently to ambient before use.

Shelf life: Follow the CoA/Spec Sheet and retest criteria; if discoloration or unusual odor changes are observed, purify by distillation prior to critical applications.

Research use note: For research use only (per Product Data).

Structure and Identity

Brief intro: Pyridine is the parent six-membered aromatic azine; a benzene ring in which one CH is replaced by nitrogen, conferring basicity and strong ligand properties.

• Item-specific identifiers from Product Data:

  • CAS: 110-86-1
  • SKU: P141189
  • InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
  • 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.

• Literature identity (for reference; not item-specific specs):

  • Common name: Pyridine
  • Molecular formula (literature): C5H5N
  • Molecular weight (literature): 79.10 g/mol
  • Canonical SMILES (literature): n1ccccc1
  • InChIKey (literature): JUJWROOIHBZHMG-UHFFFAOYSA-N

• Structural features (general chemistry):

  • Heteroaromatic, six-membered ring with one ring nitrogen (sp2) at the 1-position.
  • Planar, aromatic (6 π-electrons). Nitrogen lone pair is in an sp2 orbital orthogonal to the π-system, making it a Lewis base and poor π-donor.
  • No stereocenters; 2D depiction: a hexagon with alternating double bonds and one N atom; ring positions 2/6 are α to N, 3/5 are β, 4 is γ.
  • Typical coordination mode: monodentate N-donor to metals; readily quaternizes to pyridinium salts with strong electrophiles.

Synthetic Utility

Functional profile (general chemistry):

• Lewis base/Brønsted base: Moderately basic (pKaH ≈ 5.2) enabling acid scavenging without high nucleophilicity; forms stable pyridinium salts with HX.
• Nucleophile at nitrogen: Quaternization with alkyl/benzyl halides gives pyridinium salts, useful as phase-transfer agents or activated species (e.g., Mukaiyama reagent analogs based on substituted pyridines).
• N-oxide chemistry: Oxidation to pyridine N-oxide enables directed electrophilic substitution at the 4-position, then deoxygenation (e.g., via POCl3), providing access to 4-substituted pyridines.
• Ligand properties: Coordinates to transition metals (e.g., Pd, Cu, Fe) affecting catalytic activity/chemoselectivity; can be used to modulate Lewis acidity or stabilize reactive intermediates.
• Reagent formation: Basis for pyridinium chlorochromate (PCC), pyridinium dichromate (PDC), and Collins reagent—selective oxidation of alcohols to carbonyl compounds under mild conditions.

Strategic uses:

• Acylation/sulfonylation media: Suppresses over-acylation and polymerization by sequestering HCl; improves solubility of acylating agents and substrates.
• Halogenation/dehydration assists: In concert with SOCl2, POCl3, or P2O5, promotes chlorination/dehydration transformations (e.g., amide → nitrile; alcohol → chloride) with controlled exotherms.
• Protecting-group chemistry: Participates in formation of acyl/aryl imidates and related intermediates; pyridinium species as activating groups.

Limitations:

• Odor/toxicity and coordinating nature can inhibit sensitive catalysts; alternative bases or sterically hindered pyridines (2,6-lutidine, collidine) may be preferable.

Target Specificity

Not applicable. This product is a small-molecule solvent/base (pyridine), not a biological targeting reagent (e.g., antibody, ligand-specific probe). No antigen/epitope/isotype information applies.