6-Chloro-3-methoxy-2-nitropyridine: Properties & Synthesis Uses

6-Chloro-3-methoxy-2-nitropyridine is a halogenated, methoxy-substituted nitropyridine that serves as a versatile electrophilic building block for the synthesis of pharmaceutically relevant heterocyclic compounds.

Chemical Name

6-Chloro-3-methoxy-2-nitropyridine

SKU

C191276

Molecular Formula

C6H5ClN2O3

Molecular Weight

188.57 g/mol

Key Functional Groups

Chloro, methoxy, nitro substituents on a pyridine ring

Primary Use

Electrophilic intermediate in heterocyclic and medicinal chemistry synthesis

Chemical Identity and Structure

6-Chloro-3-methoxy-2-nitropyridine (CAS registry; molecular formula C₆H₅ClN₂O₃; MW 188.57 g/mol) is a trisubstituted pyridine bearing a chlorine atom at the 6-position, a methoxy group at the 3-position, and a nitro group at the 2-position. This precise arrangement of electron-withdrawing (nitro, chloro) and electron-donating (methoxy) groups creates a highly differentiated ring system with predictable and tunable reactivity. The nitro group at the 2-position strongly activates the adjacent C–Cl bond toward nucleophilic aromatic substitution (S_NAr), making the chlorine an excellent leaving group under mild conditions. The methoxy substituent at the 3-position can itself be displaced or retained depending on reaction conditions, offering further synthetic flexibility.

Synthetic Applications in Medicinal and Heterocyclic Chemistry

The combination of an activating nitro group and a displaceable chlorine makes 6-Chloro-3-methoxy-2-nitropyridine a valuable electrophilic building block in pharmaceutical and agrochemical research. The C–Cl bond at the 6-position undergoes efficient S_NAr reactions with a broad range of nitrogen, oxygen, and sulfur nucleophiles, including amines, alkoxides, and thiolates, enabling rapid diversification of the pyridine scaffold. Subsequent transformations of the nitro group—such as reduction to an amine—open pathways to aminopyridines, diaminopyridines, and fused bicyclic systems such as imidazopyridines and pyrrolopyridines, which are privileged scaffolds in drug discovery. The retained methoxy group provides an additional handle for further functionalization or modulation of physicochemical properties such as lipophilicity and metabolic stability. This multifunctional reactivity profile makes the compound particularly attractive for building focused compound libraries and for the early-stage synthesis of bioactive lead structures.

Handling, Storage, and Safety Guidelines

As with all nitroarene and halogenated aromatic compounds, appropriate safety precautions should be observed when working with 6-Chloro-3-methoxy-2-nitropyridine. Personal protective equipment including chemical-resistant gloves, safety glasses, and a laboratory coat should be worn at all times. Handling should be performed in a well-ventilated fume hood to minimize inhalation exposure to dust or vapors. The compound should be stored in a tightly sealed container in a cool, dry, well-ventilated area, away from moisture, heat sources, and incompatible materials such as strong reducing agents or bases. Users should consult the product Safety Data Sheet (SDS) provided by Aladdin Scientific before use for full hazard classification, first-aid measures, and disposal requirements in compliance with local regulations. Waste containing this compound must be disposed of according to applicable environmental regulations.

Quality and Availability from Aladdin Scientific

Aladdin Scientific supplies 6-Chloro-3-methoxy-2-nitropyridine (SKU: C191276) as a research-grade reagent intended for laboratory use in synthesis and chemical development. Each lot is subject to quality control procedures to ensure consistent purity and identity. Researchers are encouraged to review the certificate of analysis (CoA) available for each specific lot prior to use. For information regarding current stock levels, available pack sizes, pricing, and bulk or custom quantity inquiries, please contact Aladdin Scientific's technical sales team or visit the product page directly. Aladdin Scientific is committed to providing reliable, well-characterized reagents that support reproducible scientific research across pharmaceutical, agrochemical, and materials science applications.

Frequently asked questions

What makes 6-Chloro-3-methoxy-2-nitropyridine useful as a synthetic building block?

The compound contains three orthogonally reactive functional groups on a pyridine ring: a nitro group that activates the adjacent chlorine toward nucleophilic aromatic substitution, a displaceable chlorine leaving group, and a methoxy group that can be retained or further functionalized. This versatility allows chemists to selectively modify different positions in a controlled sequence, making it highly valuable for constructing complex heterocyclic architectures.

How should the chlorine substituent in 6-Chloro-3-methoxy-2-nitropyridine be selectively displaced?

The chlorine at the 6-position is activated by the adjacent 2-nitro group, making it susceptible to nucleophilic aromatic substitution (SᵎSAr) with nitrogen, oxygen, and sulfur nucleophiles under relatively mild conditions. Reactions are typically performed in polar aprotic solvents such as DMF or DMSO, often with a base to neutralize the acid generated, and at temperatures ranging from ambient to moderate heating depending on the nucleophile reactivity.

What downstream transformations are possible after nucleophilic substitution of the chlorine?

After displacement of the chlorine, the nitro group at the 2-position can be reduced to a primary amine using standard methods such as catalytic hydrogenation or iron/acetic acid reduction, revealing an aminopyridine intermediate. This amine can then participate in cyclization reactions to form fused heterocycles such as imidazopyridines or pyrrolopyridines. The methoxy group offers an additional site for further chemical elaboration if required.

How should 6-Chloro-3-methoxy-2-nitropyridine be stored to maintain stability?

The compound should be stored in a tightly sealed container under cool, dry conditions away from light, moisture, and incompatible materials such as strong reducing agents. Consulting the Aladdin Scientific SDS and CoA for specific storage temperature recommendations and shelf-life information for a given lot is strongly advised.

References

1. March, J. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure. Wiley-Interscience. General reference for nucleophilic aromatic substitution mechanisms.
2. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry. Oxford University Press. General reference for heterocyclic chemistry and nitro group transformations.
3. Aladdin Scientific. Product Page: 6-Chloro-3-methoxy-2-nitropyridine, SKU C191276. Aladdin Scientific catalog.

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