4-Chloro-2,6-Dimethyl-7H-pyrrolo[2,3-d]pyrimidine: Properties & Uses
4-Chloro-2,6-Dimethyl-7H-pyrrolo[2,3-d]pyrimidine: Properties & Uses
4-chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine is a bicyclic heterocyclic compound widely employed as a versatile synthetic building block in medicinal chemistry, particularly for the preparation of pyrrolopyrimidine-based kinase inhibitors and other biologically active small molecules.
- IUPAC Name
- 4-chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine
- SKU
- C174813
- Molecular Formula
- C8H8ClN3
- Molecular Weight
- 181.62 g/mol
- Core Scaffold
- Pyrrolo[2,3-d]pyrimidine (bicyclic: pyrimidine fused with pyrrole)
- Key Reactive Site
- C-4 chloro substituent, amenable to nucleophilic aromatic substitution
- Primary Application
- Synthetic intermediate for kinase inhibitors and bioactive heterocycles
Chemical Structure and Key Physicochemical Properties
4-Chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine belongs to the pyrrolopyrimidine family of bicyclic nitrogen heterocycles, in which a pyrrole ring is fused at its [2,3-d] positions to a pyrimidine ring. The compound carries three important substituents: a chlorine atom at C-4, and methyl groups at C-2 and C-6. The molecular formula is C8H8ClN3 with a molecular weight of approximately 181.62 g/mol.
The pyrrolo[2,3-d]pyrimidine scaffold is a purine bioisostere, meaning it mimics the spatial and electronic properties of naturally occurring purines found in adenine and guanine. This bioisosteric relationship underlies its broad utility in drug discovery. The C-4 chlorine atom is particularly reactive toward nucleophilic aromatic substitution (SNAr), enabling straightforward displacement by amines, thiols, and other nucleophiles under mild conditions. The two methyl groups modulate the electron density of the ring system and can influence binding interactions in biological targets.
Synthesis Utility and Reactivity
The primary synthetic value of 4-chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine lies in its electrophilic C-4 position. The electron-withdrawing character of the pyrimidine nitrogen atoms activates the ring toward nucleophilic attack, making the C-4 chloride an excellent leaving group in SNAr reactions. Researchers routinely employ this compound to introduce diverse amine-containing fragments — including anilines, alkylamines, and amino-heterocycles — generating a wide library of 4-amino-pyrrolopyrimidine analogues in one straightforward step.
Beyond SNAr, the compound can participate in palladium-catalyzed cross-coupling reactions (e.g., Suzuki–Miyaura, Buchwald–Hartwig) at the C-4 position, further expanding the chemical space accessible from this scaffold. The free N-7 (NH) of the pyrrole ring offers an additional handle for N-alkylation or N-acylation, enabling elaboration of the bicyclic core. The methyl group at C-6 on the pyrrole ring can also serve as a site for further functionalization under appropriate conditions. This multifunctionality makes the compound an efficient starting point for parallel synthesis and structure–activity relationship (SAR) campaigns.
Applications in Drug Discovery and Medicinal Chemistry
The pyrrolo[2,3-d]pyrimidine scaffold is well established in the medicinal chemistry literature as a privileged structure for kinase inhibition. Because protein kinases recognize adenosine triphosphate (ATP) through its adenine moiety, purine bioisosteres such as pyrrolopyrimidines can occupy the ATP-binding pocket and competitively inhibit kinase activity. Researchers have employed pyrrolopyrimidine-based compounds as leads or tool compounds against a range of kinases, including Janus kinases (JAKs), cyclin-dependent kinases (CDKs), and receptor tyrosine kinases.
4-Chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine, with its reactive C-4 chloride, serves as a key precursor in multi-step syntheses of such inhibitors. By varying the amine nucleophile introduced at C-4, chemists can rapidly generate focused libraries to explore SAR and optimize selectivity, potency, and pharmacokinetic properties. Beyond kinase inhibitors, pyrrolopyrimidine derivatives have been explored in antiviral, antiparasitic, and anticancer research programs, further demonstrating the broad relevance of this building block.
Handling, Storage, and Safety Considerations
As with most reactive chloro-heterocyclic intermediates, 4-chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine should be handled with standard laboratory precautions. Personnel should wear appropriate personal protective equipment (PPE), including lab coat, chemical-resistant gloves, and eye protection. Work should be performed in a well-ventilated area or fume hood to minimize inhalation exposure.
The compound should be stored in a cool, dry, and well-ventilated location, away from moisture and incompatible materials such as strong bases, strong oxidizers, and reactive nucleophiles that could cause premature reaction at the C-4 chloride. Containers should be kept tightly sealed when not in use. Researchers are advised to consult the Safety Data Sheet (SDS) provided by Aladdin Scientific for complete hazard information, first-aid measures, and disposal guidelines prior to use.
Frequently asked questions
What makes the C-4 chlorine in 4-chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine reactive?
The electron-withdrawing pyrimidine nitrogen atoms reduce electron density at C-4, making it susceptible to nucleophilic aromatic substitution (SᵊAr). This activation allows amines, thiols, and other nucleophiles to displace the chloride efficiently under mild conditions, providing straightforward access to diverse 4-substituted pyrrolopyrimidine analogues.
Why is the pyrrolo[2,3-d]pyrimidine scaffold important in kinase inhibitor research?
The pyrrolo[2,3-d]pyrimidine ring system is a purine bioisostere that can mimic the adenine moiety of ATP, allowing these compounds to bind competitively to the ATP-binding site of protein kinases. This structural mimicry has made pyrrolopyrimidines a widely exploited privileged scaffold in the discovery of selective kinase inhibitors for oncology and inflammatory disease applications.
Can 4-chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine be used in palladium-catalyzed cross-coupling reactions?
Yes. The C-4 chloride can serve as the electrophilic partner in palladium-catalyzed reactions such as Suzuki–Miyaura (with boronic acids) and Buchwald–Hartwig amination (with primary or secondary amines), in addition to classical SᵊAr chemistry. These cross-coupling pathways provide complementary routes to functionalized pyrrolopyrimidine derivatives for SAR exploration.
How should 4-chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine be stored to maintain its integrity?
The compound should be stored in a tightly sealed container in a cool, dry, and well-ventilated location, away from moisture, strong bases, and reactive nucleophiles. Always consult the Aladdin Scientific Safety Data Sheet for product-specific storage temperature recommendations and handling precautions.
References
- Textbook-level knowledge: Taylor, E. C. et al., Chemistry of Heterocyclic Compounds — Pyrimidines. General principles of pyrrolo[2,3-d]pyrimidine reactivity and bioisosterism with purines.
- General reference: Müller, S.; Jordine, M. Privileged scaffolds in medicinal chemistry: design, synthesis, evaluation. RSC Drug Discovery Series. (General discussion of pyrrolopyrimidines as privileged kinase inhibitor scaffolds.)
- Aladdin Scientific product page: 4-chloro-2,6-dimethyl-7H-pyrrolo[2,3-d]pyrimidine, SKU C174813. Aladdin Scientific, Shanghai.
Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.
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