4-Chloro-2-nitro-1-(trifluoromethoxy)benzene: Properties & Uses
4-Chloro-2-nitro-1-(trifluoromethoxy)benzene: Properties & Uses
4-Chloro-2-nitro-1-(trifluoromethoxy)benzene is a halogenated, electron-deficient aromatic building block combining a trifluoromethoxy group, a nitro substituent, and a chloro leaving group on a single benzene ring, making it a versatile intermediate in pharmaceutical and agrochemical synthesis.
- Chemical Name
- 4-Chloro-2-nitro-1-(trifluoromethoxy)benzene
- Molecular Formula
- C7H3ClF3NO3
- Molecular Weight
- 241.55 g/mol
- Key Functional Groups
- Trifluoromethoxy (–OCF3), nitro (–NO2), chloro (–Cl)
- Primary Application
- Pharmaceutical and agrochemical intermediate; nucleophilic aromatic substitution substrate
- SKU
- C193452
Chemical Structure and Electronic Properties
4-Chloro-2-nitro-1-(trifluoromethoxy)benzene features a benzene ring bearing three distinct substituents: a trifluoromethoxy group (–OCF3) at position 1, a nitro group (–NO2) at position 2, and a chlorine atom at position 4. Both the nitro and trifluoromethoxy groups are strongly electron-withdrawing, rendering the ring highly electron-deficient. This electronic depletion activates the ring toward nucleophilic aromatic substitution (SNAr) reactions, particularly at the carbon bearing the chloro leaving group.
The –OCF3 group is notable for its strong inductive electron-withdrawing character combined with moderate lipophilicity enhancement (π = +0.88 for OCF3 vs benzene), a combination that is highly valued in drug discovery for improving membrane permeability and metabolic stability of candidate molecules. The ortho-positioned nitro group further activates the ipso carbon toward SNAr by stabilizing the Meisenheimer complex intermediate through resonance delocalization of negative charge.
Synthesis and Reactivity
The compound participates most prominently in nucleophilic aromatic substitution, where the chloride serves as the leaving group. Amines, alkoxides, and thiolates can displace the chloride under relatively mild conditions owing to the strong combined activation by the ortho-nitro and the trifluoromethoxy groups. These reactions typically proceed in polar aprotic solvents such as DMF, DMSO, or NMP in the presence of a base such as K2CO3 or Cs2CO3.
Reduction of the nitro group—using catalytic hydrogenation (H2/Pd-C) or chemical reductants such as iron in acetic acid—affords the corresponding aniline derivative, a valuable amino-trifluoromethoxy-chlorobenzene intermediate that can be further elaborated via acylation, sulfonylation, or heterocycle formation. The chlorine atom also participates in palladium-catalyzed cross-coupling reactions (Suzuki, Buchwald–Hartwig) to introduce aryl, vinyl, or amino fragments, expanding the diversity of accessible target structures.
Applications in Pharmaceutical and Agrochemical Research
Fluorinated aromatic intermediates bearing nitro and halogen substituents are workhorses of medicinal chemistry. The trifluoromethoxy group in this compound can improve bioavailability, increase binding affinity through hydrophobic interactions, and confer resistance to oxidative metabolism—properties routinely exploited in the design of CNS-active agents, kinase inhibitors, and antiparasitic compounds.
In agrochemical research, OCF3-containing aromatics are used as building blocks for herbicides, fungicides, and insecticides, where the fluorine-rich moiety contributes to both biological potency and environmental half-life modulation. The chloro substituent provides a synthetic handle for further diversification, while the nitro group can be retained for biological activity or reduced to an amine for downstream functionalization.
Handling, Storage, and Safety Considerations
As with all nitroaromatic and halogenated compounds, appropriate laboratory safety precautions must be observed when handling 4-Chloro-2-nitro-1-(trifluoromethoxy)benzene. The compound should be handled in a well-ventilated fume hood, and personal protective equipment including nitrile gloves, safety glasses, and a lab coat must be worn at all times.
The material should be stored in a tightly sealed container away from heat sources, ignition sources, and incompatible materials such as strong oxidizers and bases. Recommended storage conditions are typically at room temperature in a cool, dry location unless the specific lot certificate of analysis specifies otherwise. Consult the Safety Data Sheet (SDS) supplied by Aladdin Scientific for complete hazard classification, first-aid measures, and disposal instructions before use.
Frequently asked questions
What makes 4-Chloro-2-nitro-1-(trifluoromethoxy)benzene reactive toward nucleophilic aromatic substitution?
The combined electron-withdrawing effects of the ortho-nitro group and the trifluoromethoxy group strongly deplete electron density on the aromatic ring. This activation stabilizes the anionic Meisenheimer complex formed during SNAr, lowering the activation barrier and allowing nucleophiles such as amines and alkoxides to displace the chloride leaving group under mild conditions.
Can the chloro substituent in this compound be used in palladium-catalyzed cross-coupling reactions?
Yes. Although aryl chlorides are generally less reactive than aryl bromides or iodides in cross-coupling, the electron-withdrawing substituents on this ring increase its oxidative addition reactivity with palladium(0) catalysts. With appropriate ligands (e.g., bulky phosphines) and optimized conditions, Suzuki–Miyaura and Buchwald–Hartwig couplings can be performed effectively.
How should I store 4-Chloro-2-nitro-1-(trifluoromethoxy)benzene to maintain product integrity?
Store the compound in a tightly closed container in a cool, dry, and well-ventilated area, away from sources of heat and ignition and from incompatible materials such as strong oxidizers. Always refer to the Aladdin Scientific SDS and certificate of analysis for lot-specific storage requirements and shelf-life information.
What solvents are recommended for reactions involving this compound?
Polar aprotic solvents such as DMF, DMSO, and NMP are generally recommended for nucleophilic aromatic substitution reactions involving this compound, as they stabilize the charged transition state without protonating the nucleophile. For palladium-catalyzed couplings, THF, dioxane, or toluene mixed with aqueous base are commonly employed.
References
- Hansch, C.; Leo, A.; Taft, R. W. A survey of Hammett substituent constants and resonance and field parameters. Chemical Reviews, 1991, 91(2), 165–195. doi:10.1021/cr00002a004
- Leroux, F. Trifluoromethoxy group: a unique and versatile motif in agrochemistry and pharmaceuticals. ChemBioChem, 2004, 5(5), 644–649.
- Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed. Oxford University Press, 2012. Chapter on Nucleophilic Aromatic Substitution.
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