The construction of fused nitrogen-containing heterocycles is an important part of modern pharmaceutical chemistry. In the development of Risdiplam, a key structural feature is the 2,8-dimethylimidazo[1,2-b]pyridazine fragment. Preparing this fused heterocyclic system requires a suitably substituted pyridazine starting material.
6-Chloro-4-methylpyridazin-3-amine (CAS 64068-00-4) is one such building block. Its amino group and adjacent methyl-substituted pyridazine framework provide the structural basis for subsequent heterocycle formation.
Chemical Profile and Specifications
The compound belongs to the pyridazine family of nitrogen-containing heterocycles. Its structure combines an amino group, a chlorine substituent, and a methyl group on the pyridazine ring.
- · Product Name: 6-Chloro-4-methylpyridazin-3-amine
- · CAS Number: 64068-00-4
- · Molecular Formula: C₅H₆ClN₃
- · Molecular Weight: 143.57 g/mol
- · Synonyms: 3-Amino-6-chloro-4-methylpyridazine; 6-Chloro-4-methyl-3-pyridazinamine
- · Typical Purity: 98% as listed in the supplied product specification
- · Physical Form: Solid
PubChem and independent chemical supplier references confirm the CAS number, molecular formula, and molecular weight.
How It Contributes to the Risdiplam Heterocyclic Framework
The synthetic importance of this compound comes from its ability to participate in heterocyclization reactions.
Its adjacent amino and methyl-substituted positions provide a useful arrangement for constructing the imidazo[1,2-b]pyridazine ring system. In published Risdiplam-related synthetic routes, 6-chloro-4-methylpyridazin-3-amine is reacted with suitable halogenated carbonyl compounds or related reagents to form 6-chloro-2,8-dimethylimidazo[1,2-b]pyridazine.
This fused heterocycle can then serve as a platform for further functionalization and incorporation into the Risdiplam molecular structure.
A 2025 research article discusses this pyridazine starting material as part of the preparation of key Risdiplam intermediates. Patent literature also reports its conversion into the corresponding fused imidazopyridazine derivative.
Why Pyridazine Building Blocks Matter in Pharmaceutical Chemistry
Pyridazine derivatives are useful in medicinal chemistry because their nitrogen-rich ring systems provide opportunities to adjust molecular properties and introduce different substituents.
For process development, 6-Chloro-4-methylpyridazin-3-amine offers several useful structural features:
- · The amino group provides a reactive site for ring-forming transformations.
- · The methyl substituent contributes to the substitution pattern of the fused heterocycle.
- · The chlorine atom can serve as a functional handle for subsequent chemical modification.
- · The compact heteroaromatic framework supports the construction of more complex pharmaceutical structures.
These features make it a relevant intermediate for heterocyclic synthesis rather than merely a general-purpose pyridazine derivative.
Quality Control and Procurement Considerations
The purity of this compound can directly affect downstream cyclization and purification. Buyers should therefore evaluate:
Chemical identity: Confirm CAS 64068-00-4, molecular formula, and structural identity.
Assay and related substances: Check chromatographic purity and potential positional-isomer impurities.
Residual starting materials: Pay attention to unreacted pyridazine precursors and other process-related impurities.
Physical consistency: Review appearance, melting behavior, and batch uniformity.
Documentation: Request a batch-specific Certificate of Analysis and supporting analytical data.
Positional-isomer control deserves particular attention because closely related pyridazine structures may complicate downstream separation.
SHLZ Pharma: Pharmaceutical Intermediate Development
Shanghai Lizhuo Pharmaceutical Technology Co., Ltd. provides pharmaceutical intermediate and API R&D, customization, and production services.
According to its official company profile, SHLZ Pharma operates a 1,000-square-meter R&D laboratory and two pilot production workshops. Its equipment supports reactions across a broad temperature range, including low-temperature and ultra-low-temperature processes. The company also reports customization capabilities from grams to kilograms and pilot/factory production from hundreds of kilograms to tons.
For customers sourcing heterocyclic intermediates, these capabilities can be relevant when discussing process optimization, impurity control, and supply requirements.
Conclusion
6-Chloro-4-methylpyridazin-3-amine (CAS 64068-00-4) is a useful pyridazine building block in Risdiplam-related synthetic chemistry. Its amino and methyl-substituted ring structure supports the formation of the 2,8-dimethylimidazo[1,2-b]pyridazine framework.
For pharmaceutical procurement, identity confirmation, positional-isomer control, chromatographic purity, and batch consistency should be considered together.
Post time: Nov-13-2026
