2-Chloro-9H-Purine: Properties, Uses & FAQs

2-Chloro-9H-purine is a halogenated purine heterocycle widely used as a versatile synthetic building block for the preparation of nucleoside analogs, antiviral agents, and other biologically active purine derivatives.

CAS Number

10030-78-1

Molecular Formula

C₅H₃ClN₄

Molecular Weight

154.56 g/mol

Appearance

White to off-white crystalline powder

Aladdin SKU

C174896

Key Application

Intermediate in purine nucleoside analog and pharmaceutical synthesis

What Is 2-Chloro-9H-Purine?

2-Chloro-9H-purine (CAS 10030-78-1) is a halogenated derivative of the naturally occurring purine base in which a chlorine atom replaces the hydrogen at the 2-position of the bicyclic purine ring system. Its molecular formula is C₅H₃ClN₄ and its molecular weight is approximately 154.56 g/mol. The compound presents as a white to off-white crystalline solid and is soluble in polar aprotic solvents such as dimethyl sulfoxide (DMSO) and dimethylformamide (DMF), and sparingly soluble in water.

The electron-deficient nature of the purine ring, combined with the leaving-group ability of the chlorine substituent, makes 2-chloro-9H-purine highly reactive toward nucleophilic substitution. This reactivity is exploited extensively in medicinal chemistry and chemical biology to introduce diverse functional groups or heteroatom-containing side chains at the 2-position of the purine scaffold.

Chemical Properties and Stability

2-Chloro-9H-purine possesses the fused imidazole-pyrimidine ring system characteristic of all purines. The chlorine at C-2 renders this position susceptible to nucleophilic aromatic substitution (SNAr), enabling reactions with amines, alcohols, thiols, and organometallic reagents under appropriate conditions. The N-9 position (NH) remains available for N-alkylation or glycosylation reactions to produce N-9-substituted products relevant to nucleoside chemistry.

The compound is stable as a solid when stored in a cool, dry, well-ventilated location away from moisture and light. Prolonged exposure to moisture or acidic/basic conditions may cause hydrolysis of the C–Cl bond. Recommended storage temperature is typically 2–8 °C or room temperature under desiccated conditions; researchers should consult the product certificate of analysis for confirmed storage specifications.

Applications in Synthesis and Research

2-Chloro-9H-purine serves as a key intermediate in the synthesis of a broad range of pharmacologically important compounds. Its principal applications include:

• Nucleoside analog synthesis: The compound can be glycosylated at N-9 to afford 2-chloropurine nucleosides, which are precursors to antiviral and anticancer nucleoside drugs. For example, cladribine (2-chlorodeoxyadenosine) is derived from a 2-chloropurine intermediate.
• Medicinal chemistry: SNAr reactions with various amines yield 2-aminopurine derivatives that serve as kinase inhibitors, adenosine receptor ligands, and other bioactive scaffolds.
• Chemical biology probes: Modified purines synthesized from 2-chloro-9H-purine are used as fluorescent probes, photoaffinity labels, and activity-based probes for nucleotide-binding proteins.
• Heterocyclic library construction: Its bifunctional reactivity (C-2 and N-9) makes it valuable for combinatorial chemistry and diversity-oriented synthesis of purine libraries.

Handling, Safety and Storage

Although 2-chloro-9H-purine is not classified as an extremely hazardous substance, it should be handled with appropriate laboratory precautions. Researchers should wear nitrile gloves, safety goggles, and a laboratory coat when weighing or transferring the compound. Operations that generate dust should be carried out in a fume hood or with appropriate respiratory protection.

The compound should be stored tightly sealed in its original container in a cool, dry place. Keep away from incompatible materials including strong oxidising agents, strong bases, and strong acids. In the event of skin or eye contact, rinse thoroughly with water and seek medical advice if irritation persists. Disposal should be carried out in accordance with local regulations for chemical waste.

Note: Always consult the current Safety Data Sheet (SDS) provided with the product for authoritative hazard classifications, first-aid measures, and disposal guidance specific to your jurisdiction.

Ordering 2-Chloro-9H-Purine from Aladdin Scientific

Aladdin Scientific supplies 2-chloro-9H-purine under catalog number C174896. To place an order, search for the SKU or CAS number (10030-78-1) on the Aladdin Scientific website. Bulk quantities and custom packaging may be available upon request; contact our sales team for pricing and lead-time information.

Each lot is accompanied by a Certificate of Analysis (CoA) confirming purity, appearance, and other quality parameters. Researchers requiring additional documentation such as an SDS or spectral data should contact customer service. For institutional purchase orders, Aladdin Scientific accepts standard procurement workflows including purchase-order invoicing.

Frequently asked questions

What is 2-chloro-9H-purine used for in organic synthesis?

2-Chloro-9H-purine is primarily used as a reactive building block for the synthesis of purine nucleoside analogs, kinase inhibitors, and other pharmacologically active compounds. The electrophilic chlorine at C-2 undergoes nucleophilic aromatic substitution with amines, thiols, and alcohols, while the N-9 position can be alkylated or glycosylated to produce nucleoside-type structures. This bifunctional reactivity makes it indispensable in medicinal chemistry and chemical biology research.

How should 2-chloro-9H-purine be stored to maintain stability?

The compound should be stored as a tightly sealed solid in a cool, dry, and well-ventilated location, away from moisture, light, and incompatible reagents such as strong acids, bases, and oxidising agents. Storage at 2–8 °C under desiccated conditions is commonly recommended, but researchers should verify the recommended conditions on the current Certificate of Analysis or Safety Data Sheet supplied with their specific lot.

Is 2-chloro-9H-purine soluble in common laboratory solvents?

2-Chloro-9H-purine dissolves well in polar aprotic solvents such as DMSO and DMF, which are the preferred media for most synthetic applications. It has limited solubility in water and common alcohols. If aqueous conditions are required, warming the solution or using a co-solvent system may improve dissolution. Researchers should determine the exact solubility empirically for their specific experimental conditions.

What is the relationship between 2-chloro-9H-purine and cladribine?

Cladribine (2-chloro-2′-deoxyadenosine), an approved drug used in the treatment of hairy cell leukemia and multiple sclerosis, is synthesized via routes that employ 2-chloropurine intermediates. Glycosylation of a 2-chloropurine building block at the N-9 position, followed by introduction of an amino group at C-6, yields the cladribine scaffold. Thus 2-chloro-9H-purine represents a key starting material in the synthetic pathway to this important nucleoside analog drug.

What purity grade of 2-chloro-9H-purine does Aladdin Scientific offer?

Aladdin Scientific offers 2-chloro-9H-purine (SKU C174896) for research use. The specific purity specification is confirmed in the Certificate of Analysis accompanying each lot. Researchers requiring a particular purity threshold for sensitive applications should contact Aladdin Scientific customer service or refer to the CoA available on the product page before ordering.

References

1. Montgomery, J. A.; Hewson, K. Nucleosides of 2-fluoroadenine. Journal of Medicinal Chemistry, 1969. (General reference for 2-chloropurine nucleoside synthesis strategies.)
2. Legraverend, M.; Grierson, D. S. The purines: potent and versatile small molecule inhibitors and ligands. Bioorganic & Medicinal Chemistry, 2006, 14(12), 3987–4006. doi:10.1016/j.bmc.2006.02.013
3. Carson, D. A. et al. Synthesis and biological activity of 2-chloro-2′-deoxyadenosine (cladribine). Proceedings of the National Academy of Sciences USA, 1984.

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