2'-Bromo-4'-methylpropiophenone
Founded in 2017, Sigma Chemical Co., Ltd. supplies over 100 countries with high-quality chemicals. We are dedicated to safety, innovation, and global cooperation.
Product Description
2'-Bromo-4'-methylpropiophenone is a brominated and methyl-substituted aromatic ketone that serves as a laboratory intermediate for research purposes only: its aryl-bromine bond can be used in metal-catalyzed cross-coupling reactions and other derivatization reactions, while the propiophenone core provides a versatile carbonyl platform, making it valuable in rational structure-activity relationship (SAR) studies, drug/agrochemical precursor synthesis routes, and analytical reference work. However, due to this same reactivity, it has also been misused as a precursor to 4-methylmethcathinone analogs and is therefore regulated in many countries and regions.
Regulatory Note: Due to its potential use as a precursor in the synthesis of certain controlled substances, its sale and use may be monitored or restricted in some jurisdictions.
Synthesis and Production
Primary Method: Typically synthesized via a Friedel-Crafts acylation.
- Reactants: 2-Bromo-4-methylbenzene and propionyl chloride (or propionic anhydride).
- Catalyst: A Lewis acid, commonly aluminum chloride (AlCl₃).
- Conditions: The reaction is conducted under anhydrous conditions at low temperatures (e.g., 0–5 °C) to minimize side reactions.
- Reported Yield: Approximately 70–80% isolated yield after aqueous workup.
Alternative Method: Could potentially be accessed via cross-coupling reactions (e.g., Negishi or Suzuki coupling) between a 2-bromo-4-methylbenzoyl derivative and an ethyl organometallic reagent, though this is less common.
Uses and Applications
-
Primary Use: Serves as a versatile organic synthesis intermediate or building block in pharmaceutical, agrochemical, and fine chemical research.
-
Key Functional Groups: The molecule contains two reactive sites:
-
Aromatic Bromine (C-Br): Can participate in various metal-catalyzed cross-coupling reactions (e.g., Suzuki, Sonogashira) or nucleophilic aromatic substitution.
-
α-Bromo Ketone (C(=O)-CH₂-Br): The bromine at the alpha position to the carbonyl is a good leaving group, making the compound a useful electrophile for nucleophilic substitution (SN2) to form new carbon-heteroatom or carbon-carbon bonds.
-
-
Specific Applications:
-
Precursor for synthesizing heterocycles, substituted ketones, and alcohols.
-
Building block for introducing specific side chains or functional groups into target molecules.
-
Laboratory-scale chemical research to study the reactivity of substituted propiophenones.
-
Chemical and Physical Properties
Identifiers & Structure
-
IUPAC Name: 1-(2-bromo-4-methylphenyl)propan-1-one
-
Canonical SMILES: CCC(=O)C1=C(C=C(C=C1)C)Br
-
InChIKey: ZCQPLHJQGPEELZ-UHFFFAOYSA-N
Computed Physicochemical Properties
-
Exact Mass: 225.99933 Da
-
XLogP3: 3.1 (indicates moderate lipophilicity)
-
Hydrogen Bond Donor Count: 0
-
Hydrogen Bond Acceptor Count: 1
-
Rotatable Bond Count: 2
-
Topological Polar Surface Area (TPSA): 17.1 Ų
-
Complexity: 167
Reported Physical Properties
-
Appearance: Typically a clear pale-yellow to colorless liquid or low-melting solid (white to light yellow crystals).
-
Melting Point: ~28–31 °C (literature range); approximately 30–40 °C.
-
Boiling Point: ~120–125 °C at 6 mmHg.
-
Refractive Index (n²⁰D): ~1.565 – 1.568
-
Density: ~1.37 g/cm³ at 20 °C.
-
Solubility: Soluble in common organic solvents (ethanol, acetone, chloroform, diethyl ether); insoluble in water.
Spectral Information
-
Mass Spectrometry (MS): GC-MS data is available (Source: SpectraBase, Wiley).
-
Infrared (IR) Spectroscopy: Vapor-phase IR spectrum is available, with a characteristic carbonyl (C=O) stretch expected around 1675–1680 cm⁻¹ for the conjugated aryl ketone.
-
Nuclear Magnetic Resonance (NMR) (Typical reported values):
-
¹H NMR (CDCl₃): δ ~7.80 (d, 1H), ~7.55 (s, 1H), ~7.15 (dd, 1H, aromatic), ~2.95 (q, 2H, CH₂), ~2.40 (s, 3H, Ar-CH₃), ~1.20 (t, 3H, CH₃).
-
¹³C NMR: Carbonyl carbon (C=O) expected near 197 ppm.
-
Safety and Handling
-
Hazards: Classified as an irritant. Likely hazardous according to typical supplier Safety Data Sheets (SDS), with hazard statements such as:
-
H302: Harmful if swallowed.
-
H315: Causes skin irritation.
-
H319: Causes serious eye irritation.
-
H335: May cause respiratory irritation.
-
-
Precautions:
-
Use appropriate personal protective equipment (gloves, safety goggles).
-
Handle in a well-ventilated area, preferably a fume hood.
-
Avoid contact with skin, eyes, and clothing. Avoid inhalation of dust/vapors.
-
-
Storage: Store sealed in a cool, dry, and dark place (e.g., refrigerated) to prevent decomposition (e.g., debromination) and discoloration. Keep away from strong oxidizers and bases.