1. Product Overview
2-Acetyl-5-bromothiophene (CAS No. 5370-25-2) is a brominated thiophene derivative with the molecular formula C₆H₅BrOS and a molecular weight of 205.07 g/mol. It typically appears as white to light yellow crystalline flakes or a fine powder, and is light-sensitive. This compound features both an acetyl group and a reactive bromine atom on the thiophene ring, making it a versatile heterocyclic building block in pharmaceutical R&D, agrochemical synthesis, and materials science (e.g., OLED/thiophene-based semiconductors). It is widely used as a key intermediate for constructing bithiophene bis-imidazo[1,2-a]pyridine derivatives and phosphorus-containing fused bicyclic compounds.
Key Identifiers:
• CAS Number: 5370-25-2
• EINECS Number: 226-363-7
• MDL Number: MFCD00014528
• Molecular Formula: C₆H₅BrOS
• Molecular Weight: 205.07 g/mol
• Synonyms: 1-(5-Bromo-2-thienyl)ethanone; 5-Bromo-2-thienyl methyl ketone; 1-(5-Bromothiophen-2-yl)ethanone; Ethanone, 1-(5-bromo-2-thienyl)-
2. Key Features and Advantages
• Dual Reactive Sites: Contains both an electrophilic acetyl carbonyl and a nucleophile-friendly aryl bromide, enabling sequential functionalization (e.g., Grignard, cross-coupling, condensation).
• High Purity Available: Typically supplied at ≥98% (GC/HPLC), with optional 99% grade for sensitive pharmaceutical processes; often stabilized with Cu+HQ+MgO upon request.
• Well-Defined Physical Data: Literature-backed mp 94–96 °C (lit.), bp 103 °C at 4 mmHg, supporting reliable process design.
• Light-Sensitive but Stable Under Inert Gas: Maintains integrity for 12–24 months when stored cold (2–8 °C) under N₂/Ar in the dark.
• Versatile Heterocyclic Scaffold: Essential for building thiophene-based bioactive molecules, conjugated systems for organic electronics, and fused heterocycles.
3. Main Applications
• Pharmaceutical Intermediate: Used in synthesizing heterocyclic APIs and bithiophene bis-imidazo[1,2-a]pyridine derivatives with potential anti-inflammatory/anticancer profiles.
• Agrochemical R&D: Serves as a thiophene building block for novel fungicides, herbicides, and crop-protection agents.
• Materials Science: Precursor for thiophene-based conjugated polymers and oligomers in OLEDs, organic field-effect transistors (OFETs), and specialty semiconductors.
• Organic Synthesis: Employed in Suzuki/Miyaura, Stille, and other Pd-catalyzed cross-couplings via the aryl bromide; acetyl group allows aldol-type condensations and imine formations.
• Fine Chemical Manufacturing: Intermediate for phosphorus-containing fused bicyclic 5,6-membered compounds and custom heterocyclic libraries.
4. Technical Specifications
5. Storage and Handling
• Storage Conditions: Store in a cool, dry place under an inert atmosphere (nitrogen or argon). Keep at 2–8 °C and protect from light (amber vial or foil-wrapped container). Minimize exposure to air and moisture to prevent decomposition or discoloration. For long-term storage, seal tightly with desiccant.
• Shelf Life: 12–24 months unopened when stored as recommended; stable for several weeks at ambient temperature if kept dark and dry, but light-sensitive—avoid prolonged exposure.
• Handling Precautions: Handle in a well-ventilated area or fume hood. Avoid inhaling dust or vapors. Use personal protective equipment: N95 dust mask (or equivalent), safety goggles, nitrile gloves, and lab coat. This compound is a mild irritant to eyes, skin, and respiratory tract (GHS07, H302/H312/H315/H319/H332).
• Packaging: Reagent grade: 1 g / 5 g / 10 g / 25 g / 100 g / 500 g in amber glass vials with desiccant, optionally stabilized. Industrial grade: 1 kg / 5 kg / 25 kg fiber drums with double PE liner, filled under N₂.
6. Safety Overview
• GHS Classification: GHS07 – Warning. Hazard statements: H302 (harmful if swallowed), H312 (harmful in contact with skin), H315 (causes skin irritation), H319 (causes serious eye irritation), H332 (harmful if inhaled).
• Signal Word: Warning
• Precautionary Statements: P261 (avoid breathing dust/mist), P264 (wash after handling), P270 (do not eat/drink/smoke when using), P280 (wear protective gloves/eye protection), P301+P312 (if swallowed: call poison center if unwell), P302+P352 (if on skin: wash with soap/water), P304+P340 (if inhaled: remove to fresh air), P305+P351+P338 (if in eyes: rinse cautiously 15 min), P362 (take off contaminated clothing), P501 (dispose of contents per local regs).
• Traditional Risk/Safety: Risk codes R20/21/22 (harmful by inhalation, skin contact, ingestion) + R36/37/38 (irritant to eyes, resp. system, skin); Safety S22 (do not breathe dust), S26 (eye rinse immediately), S36/37/39 (wear suitable protective clothing/gloves/eye protection).
• First Aid Measures:
• Inhalation: Move to fresh air. If breathing difficult, give oxygen and seek medical attention.
• Skin Contact: Remove contaminated clothing. Wash thoroughly with soap and water.
• Eye Contact: Rinse immediately with flowing water for at least 15 minutes, lifting eyelids. Seek medical advice.
• Ingestion: Rinse mouth. Do NOT induce vomiting unless directed by a physician. Seek immediate medical attention.
• Firefighting: Use dry chemical, CO₂, water spray, or alcohol-resistant foam. Wear self-contained breathing apparatus.
• Disposal: Dispose as hazardous organic halide waste per local regulations. WGK Germany 3 (hazardous to waters). UN2811 for transport (toxic solids, organic, n.o.s.).
