2-Amino-5-chloropyridine
[CAS# 1072-98-6]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Pyridine compound >> Chloropyridine
• Name: 2-Amino-5-chloropyridine
• Molecular Formula: C₅H₅ClN₂
• Molecular Weight: 128.56
• CAS Registry Number: 1072-98-6
• EC Number: 214-020-4
• SMILES: C1=CC(=NC=C1Cl)N

Properties

• Melting point: 134-138 °C
• Boiling point: 127-128 °C (11 mmHg)
• Flash point: 160 °C
• Water solubility: 1 g/L (20 °C)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H332-H335
• Safety Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P317-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H332
Acute toxicity	Acute Tox.	4	H312

Discovery and Applications

2-Amino-5-chloropyridine is an important chemical compound used in the synthesis of pharmaceuticals, agrochemicals, and various organic materials. The discovery of 2-amino-5-chloropyridine can be traced back to research into substituted pyridines, a class of heterocyclic aromatic compounds that exhibit significant biological and chemical activity. The compound is characterized by a pyridine ring, a basic nitrogen-containing aromatic structure, with an amino group attached to the second carbon and a chlorine atom attached to the fifth carbon.

The synthesis of 2-amino-5-chloropyridine typically involves the chlorination of 2-aminopyridine or the amination of 5-chloropyridine. These methods provide efficient routes to produce the compound in high yields, making it readily available for industrial and research purposes. The introduction of the chlorine atom into the pyridine ring enhances the compound’s reactivity, particularly in nucleophilic substitution reactions, allowing it to serve as a versatile intermediate in the production of more complex molecules.

One of the primary applications of 2-amino-5-chloropyridine is in the pharmaceutical industry, where it is used as a building block for the synthesis of various active pharmaceutical ingredients (APIs). Its structure allows for the formation of multiple derivatives with diverse biological activities. For instance, 2-amino-5-chloropyridine is a precursor in the synthesis of certain antiviral and anticancer agents, where it contributes to the pharmacophore, the part of the molecule responsible for its biological activity. The compound’s ability to participate in the formation of hydrogen bonds and other interactions with biological targets makes it a valuable component in drug design.

In addition to its role in drug synthesis, 2-amino-5-chloropyridine is also used in the development of agrochemicals, particularly herbicides and fungicides. The compound’s chemical properties allow it to be modified into molecules that can selectively target pests or pathogens while minimizing harm to crops and the environment. The chlorine atom in the pyridine ring often enhances the efficacy of these agrochemicals, contributing to their ability to disrupt specific biological processes in target organisms.

Beyond pharmaceuticals and agrochemicals, 2-amino-5-chloropyridine finds application in materials science. It is used in the synthesis of dyes, pigments, and polymer additives, where its aromatic structure and functional groups contribute to the stability and performance of the final products. In particular, the compound’s role in the creation of light-absorbing and color-producing materials has led to its use in the textile and coatings industries. Its derivatives can be tailored to produce specific colors and properties, making it a versatile ingredient in the formulation of high-performance materials.

The chemical reactivity of 2-amino-5-chloropyridine also allows it to be used in organic synthesis as a key intermediate. It can undergo various transformations, including cross-coupling reactions, which enable the construction of complex organic molecules. This versatility makes it an essential tool in the synthesis of heterocyclic compounds, which are prevalent in both natural and synthetic chemistry.

Ongoing research into 2-amino-5-chloropyridine continues to explore its potential in new applications, particularly in the development of novel drugs and advanced materials. The compound’s ability to be easily modified and incorporated into larger chemical frameworks ensures its continued relevance in scientific research and industrial production. As the demand for efficient and effective chemical intermediates grows, 2-amino-5-chloropyridine is likely to remain a key compound in the toolbox of chemists working across various fields.

References

2015. A Novel Convenient Synthesis of Pyridinyl and Quinolinyl Triflates and Tosylates via One-Pot Diazotization of Aminopyridines and Aminoquinolines in Solution. Synthesis.
DOI: 10.1055/s-0035-1560392

2014. Validation of an LC-MS/MS method for the determination of zopiclone, N-desmethylzopiclone and 2-amino-5-chloropyridine in whole blood and its application to estimate the original zopiclone concentration in stored specimens. International Journal of Legal Medicine.
DOI: 10.1007/s00414-014-1049-2

1971. Reaction of 2-amino-5-halopyridines with methyl acrylate. Chemistry of Heterocyclic Compounds.
DOI: 10.1007/bf00473087