1-Chloro-2-methyl-3,5-dinitrobenzene: Properties & Lab Uses

1-Chloro-2-methyl-3,5-dinitrobenzene is a halogenated aromatic nitro compound widely employed as a reactive intermediate in organic synthesis, particularly in nucleophilic aromatic substitution and the preparation of specialty agrochemical and pharmaceutical scaffolds.

Molecular Formula

C₇H₅ClN₂O₄

Molecular Weight

216.58 g/mol

CAS Number

Needs review — not confirmed in source material

Functional Groups

Aryl chloride, two nitro groups, methyl substituent

Key Reactivity

Activated toward nucleophilic aromatic substitution (SNAr) due to ortho/para electron-withdrawing nitro groups

Physical State

Solid (typical for this compound class at room temperature)

SKU

C727506

Chemical Structure and Properties

1-Chloro-2-methyl-3,5-dinitrobenzene belongs to the class of polysubstituted aromatic compounds featuring a chlorine atom at the 1-position, a methyl group at the 2-position, and nitro groups at the 3- and 5-positions of the benzene ring. This specific substitution pattern creates a highly electron-deficient aromatic ring, primarily due to the strong electron-withdrawing inductive and resonance effects of the two nitro groups.

The presence of two ortho/para-directing withdrawal groups flanking the chlorine atom dramatically lowers the electron density at the carbon bearing the chlorine, thereby activating the molecule toward nucleophilic aromatic substitution (SNAr). The methyl group at the 2-position introduces steric considerations that can influence regioselectivity in subsequent reactions. The compound is expected to be a pale yellow to off-white crystalline solid with limited water solubility, consistent with other halogenated nitroaromatics of similar molecular weight.

Synthesis and Role as a Reaction Intermediate

In synthetic organic chemistry, 1-Chloro-2-methyl-3,5-dinitrobenzene serves primarily as an electrophilic building block activated for nucleophilic displacement. The chlorine leaving group is readily displaced by a variety of nucleophiles — including amines, alkoxides, and thiolates — under relatively mild conditions compared to non-activated aryl chlorides, because the flanking nitro groups stabilize the Meisenheimer complex intermediate.

This compound is therefore a valuable precursor in the synthesis of diaryl ethers, arylamines, and thioethers bearing the dinitromethylphenyl motif. Such motifs appear in the synthesis of agrochemicals, dyes, and pharmaceutical intermediates. Researchers should note that the methyl group at the 2-position may be oxidized under appropriate conditions to yield carboxylic acid derivatives, further broadening the synthetic utility of this starting material.

Safety, Handling, and Storage

As with all aromatic nitro compounds, 1-Chloro-2-methyl-3,5-dinitrobenzene must be handled with appropriate precautions. Polynitroaromatics can pose flammability and, in some cases, explosion hazards when subjected to heat, shock, or friction, particularly in bulk quantities. Users should consult the current Safety Data Sheet (SDS) supplied with the product before use.

Recommended personal protective equipment includes chemical-resistant gloves, safety goggles, and a laboratory coat. Work should be conducted in a well-ventilated fume hood to minimize inhalation of dust or vapors. The compound should be stored in a cool, dry, well-ventilated location away from strong oxidizers, reducing agents, and ignition sources. Waste disposal must comply with local and national regulations governing halogenated and nitrated aromatic waste streams.

Laboratory Applications and Research Use Cases

Researchers across medicinal chemistry, agrochemical development, and materials science utilize 1-Chloro-2-methyl-3,5-dinitrobenzene as a versatile intermediate. Key application areas include:

• Medicinal Chemistry: Construction of nitroaromatic pharmacophores and precursors to aniline-containing drug candidates via reduction of the nitro groups.
• Agrochemical Synthesis: Building block for herbicide and fungicide active ingredients featuring dinitroaniline or related motifs.
• Dye and Pigment Intermediates: Precursor to azo dyes and other colorants via coupling reactions after partial or full reduction.
• Mechanistic Studies: Model substrate for studying SNAr kinetics, Meisenheimer complex stability, and the influence of ortho-methyl steric effects on nucleophilic displacement rates.

The availability of this compound in research-grade purity from Aladdin Scientific (SKU: C727506) supports reproducible results across these application areas.

Frequently asked questions

What makes 1-Chloro-2-methyl-3,5-dinitrobenzene reactive toward nucleophilic aromatic substitution?

The two nitro groups at the 3- and 5-positions are strong electron-withdrawing groups that stabilize the anionic Meisenheimer complex formed when a nucleophile attacks the carbon bearing the chlorine leaving group. This stabilization dramatically lowers the activation energy for the substitution compared to unactivated aryl chlorides.

What nucleophiles can displace the chlorine in this compound?

A wide range of nucleophiles can displace the chlorine, including primary and secondary amines (to give arylamines), alkoxides (to give aryl ethers), and thiolates (to give aryl thioethers). Reaction conditions — solvent, temperature, and base — should be optimized for each specific nucleophile.

How should 1-Chloro-2-methyl-3,5-dinitrobenzene be stored to maintain stability?

The compound should be stored in a tightly sealed container in a cool, dry, and well-ventilated area, away from heat sources, strong oxidizers, and reducing agents. Always refer to the current SDS for the most up-to-date storage and handling guidance.

Can the nitro groups in this compound be selectively reduced?

Selective mono-reduction of one nitro group is possible using carefully controlled catalytic hydrogenation conditions or chemical reductants such as iron in acetic acid, though achieving high selectivity can be challenging given the two nitro groups. This is a topic well-documented in synthetic organic chemistry literature, and optimization is typically required for each specific substrate.

References

1. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure. Wiley-Interscience. (General reference for nucleophilic aromatic substitution and Meisenheimer complexes.)
2. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry. Oxford University Press. (General reference for SNAr reactions and polynitroaromatic reactivity.)
3. Aladdin Scientific product page for 1-Chloro-2-methyl-3,5-dinitrobenzene, SKU C727506.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.