3-Bromomethylthiophene: Properties, Uses & Handling FAQ
3-Bromomethylthiophene: Properties, Uses & Handling FAQ
3-Bromomethylthiophene is a reactive benzylic-type bromide building block bearing a thiophene ring, widely used in organic synthesis for alkylation, cross-coupling, and the construction of thiophene-containing target molecules.
- CAS Number
- 34846-65-6
- Molecular Formula
- C5H5BrS
- Molecular Weight
- 177.06 g/mol
- Aladdin SKU
- B192902
- Functional Group
- Benzylic bromide on thiophene ring (3-position)
- Typical Applications
- Alkylation reactions, Suzuki/Kumada cross-coupling precursors, nucleophilic substitution
- Storage Recommendation
- Store in a cool, dry place under inert atmosphere, away from light and moisture
What Is 3-Bromomethylthiophene and What Are Its Key Chemical Properties?
3-Bromomethylthiophene (CAS 34846-65-6, also written as 3-(bromomethyl)thiophene) is a halogenated heterocyclic compound consisting of a thiophene ring with a bromomethyl (–CH2Br) substituent at the 3-position. Its molecular formula is C5H5BrS and its molecular weight is approximately 177.06 g/mol.
The compound behaves as a benzylic-type bromide: the CH2Br group is activated by the adjacent π-system of the thiophene ring, making the carbon highly electrophilic and susceptible to nucleophilic substitution (SN2) as well as transition-metal-catalysed cross-coupling reactions. The thiophene ring itself is an electron-rich aromatic heterocycle, contributing to the compound's utility in the synthesis of pharmaceuticals, agrochemicals, and functional organic materials.
3-Bromomethylthiophene is typically a pale yellow to colourless liquid or low-melting solid at room temperature. It is sensitive to moisture and light; slow hydrolysis or oxidative decomposition may occur on prolonged exposure, so proper storage is essential.
What Are the Main Synthetic Applications of 3-Bromomethylthiophene?
3-Bromomethylthiophene is a versatile electrophilic building block in modern organic synthesis. Its primary uses include:
- Alkylation of nucleophiles: The reactive CH2Br group readily undergoes SN2 reactions with a wide range of nucleophiles including amines, thiols, alcohols, malonate esters, and organometallic reagents (e.g., Grignard reagents), enabling straightforward introduction of the 3-thienylmethyl motif.
- Cross-coupling chemistry: After conversion to the corresponding boronic acid, organozinc, or organotin species, or directly via C–Br bond activation in certain protocols, 3-bromomethylthiophene serves as a precursor for Suzuki–Miyaura, Kumada, Negishi, and Stille coupling reactions to build biaryl or heteroaryl-containing architectures.
- Pharmaceutical and agrochemical intermediates: The thienylmethyl group appears in biologically active molecules, and 3-bromomethylthiophene is used as a key intermediate in the preparation of such targets.
- Functional materials: Thiophene-containing polymers and small molecules are important in organic electronics (OFETs, OPVs); bromomethylthiophene derivatives serve as monomers or coupling partners in these synthetic programmes.
The reagent is typically used under mild conditions (room temperature to 60 °C) with appropriate base or catalyst depending on the reaction type.
How Should 3-Bromomethylthiophene Be Stored and Handled Safely?
Storage: Store 3-Bromomethylthiophene in a tightly sealed container under an inert atmosphere (nitrogen or argon) in a cool (2–8 °C recommended), dry, and dark location. Avoid exposure to moisture, air, and light to prevent hydrolysis and decomposition. Ensure the storage area is well-ventilated and segregated from incompatible materials such as strong oxidising agents and strong bases.
Handling precautions: As an organic bromide, 3-Bromomethylthiophene is a lachrymator and skin, eye, and respiratory irritant. Always handle in a well-ventilated fume hood wearing appropriate personal protective equipment (PPE): chemical-resistant gloves (e.g., nitrile), safety goggles, and a lab coat. Avoid breathing vapours or aerosols.
Waste disposal: Dispose of waste material in accordance with local, regional, and national regulations governing halogenated organic solvents and reagents. Do not pour down the drain.
First aid: In case of skin contact, wash thoroughly with soap and water. For eye contact, rinse with copious water for at least 15 minutes and seek medical attention. If inhaled, move to fresh air immediately.
Note: Always consult the current Safety Data Sheet (SDS) provided by Aladdin Scientific (SKU B192902) for complete hazard and handling information before use.
How Can I Order 3-Bromomethylthiophene from Aladdin Scientific?
3-Bromomethylthiophene is available from Aladdin Scientific under SKU B192902. To place an order:
- Online: Search for SKU B192902 or the product name on the Aladdin Scientific website and add the desired quantity to your cart. Multiple pack sizes may be available to suit laboratory needs ranging from small-scale synthesis to bulk procurement.
- Quotation requests: For large-volume orders or institutional pricing, contact the Aladdin Scientific sales team via the website enquiry form or by email/phone as listed on the Contact Us page.
- Purchase orders: Institutional customers may submit a purchase order (PO) through established procurement channels. Contact customer service to set up an account if required.
Typical shipping is under ambient or cold-chain conditions depending on the product specification; please confirm shipping requirements at the time of ordering. Aladdin Scientific ships domestically and internationally — consult the shipping and delivery policy for estimated lead times and any regional restrictions on hazardous materials.
Quality, Purity, and Specification of B192902
Aladdin Scientific's 3-Bromomethylthiophene (SKU B192902) is supplied as a research-grade reagent intended for laboratory use. Key specification points typically include:
- Purity: Research-grade purity is standard; exact purity specification (e.g., ≥95% or ≥97% by GC) should be confirmed on the current product page or Certificate of Analysis (CoA) at the time of purchase, as specifications may be updated.
- Analytical methods: Purity is typically verified by gas chromatography (GC) and/or NMR spectroscopy. A CoA is available for each lot upon request.
- Appearance: Typically a pale yellow to colourless liquid or solid.
- Lot traceability: Each batch carries a unique lot number. Request the CoA for your specific lot from Aladdin customer service or download it via the website using the lot number.
If your application requires a specific purity grade or custom packaging, please contact Aladdin Scientific's technical sales team to discuss options.
Frequently asked questions
What nucleophiles react well with 3-Bromomethylthiophene?
3-Bromomethylthiophene undergoes efficient S₂N reactions with a broad range of nucleophiles due to the activated benzylic-type CH₂Br group. Common examples include primary and secondary amines (to give thienylmethylamines), thiols (thioethers), alkoxides (ethers), stabilised carbanions such as malonate esters, and organometallic species such as Grignard or organozinc reagents. Reactions are typically conducted in polar aprotic solvents (DMF, acetonitrile, THF) with a suitable base (K₂CO₃, Et₃N) where necessary.
Is 3-Bromomethylthiophene stable at room temperature, and how should I check my sample quality before use?
3-Bromomethylthiophene is moderately sensitive to moisture, air, and light; prolonged storage under ambient conditions can lead to gradual decomposition or colour deepening. For best stability, store the reagent sealed under inert gas at 2–8 °C. Before use, inspect the sample visually for excessive darkening, and if purity is critical, verify by GC or ¹H NMR against literature chemical shifts (the CH₂Br protons appear near δ 4.5 ppm in CDCl₃). Request the batch Certificate of Analysis from Aladdin Scientific (SKU B192902) for lot-specific purity data.
Can 3-Bromomethylthiophene be used directly in palladium-catalysed cross-coupling reactions?
Benzylic bromides including 3-Bromomethylthiophene can participate in certain palladium-catalysed reactions, such as allylic/benzylic alkylation protocols; however, the C(sp³)–Br bond is less commonly employed in classical Suzuki or Heck couplings compared to aryl or vinyl halides. More commonly, the compound serves as a precursor that is first converted to an organometallic species (e.g., the Grignard reagent for Kumada coupling) or used in Pd-catalysed benzylic substitution. Reaction success depends heavily on the choice of catalyst, ligand, and base — optimisation is recommended, and literature precedent for the specific coupling should be consulted.
What is the difference between 3-Bromomethylthiophene and 3-Bromothiophene?
3-Bromomethylthiophene (3-(bromomethyl)thiophene) has a –CH₂Br group attached to the thiophene ring at the 3-position, placing the bromine on an exocyclic sp³ carbon; this makes it a benzylic-type electrophile reactive in S₂N2 and certain metal-catalysed reactions. 3-Bromothiophene, by contrast, has the bromine directly on the aromatic ring carbon (sp²), making it an aryl bromide suited for Pd- or Ni-catalysed cross-coupling (Suzuki, Kumada, etc.) under conditions typical for aryl halides. The two reagents are complementary but used in very different synthetic contexts.
What solvents are recommended for reactions involving 3-Bromomethylthiophene?
For nucleophilic substitution reactions, polar aprotic solvents such as DMF, acetonitrile, DMSO, or THF are generally preferred as they stabilise the transition state without solvating the nucleophile excessively. For reactions with organometallic reagents (e.g., Grignard formation), anhydrous diethyl ether or THF under inert atmosphere is standard. Protic solvents such as water or alcohols should be avoided unless the reaction is specifically designed for aqueous conditions, as they may promote hydrolysis of the benzylic bromide or quench organometallic intermediates.
References
- March, J.; Smith, M. B. March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 7th ed.; Wiley: Hoboken, NJ, 2013. (General reference for S₂N2 reactions of alkyl halides and benzylic bromides.)
- Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (General reference for nucleophilic substitution and heterocyclic chemistry.)
- Aladdin Scientific Product Page, SKU B192902: 3-Bromomethylthiophene. https://www.aladdin-e.com (accessed 2024).
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