A Privileged Heterocyclic Building Block for Drug Discovery, Agrochemicals, and Materials Science: 4,5-Dimethylisoxazol-3-amine (CAS# 13999-39-8)

4,5-Dimethylisoxazol-3-amine (CAS# 13999-39-8), also known as 3-amino-4,5-dimethylisoxazole, 4,5-dimethyl-1,2-oxazol-3-amine, or 4,5-dimethyl-3-isoxazolamine, is a heterocyclic isoxazole derivative with the molecular formula C₅H₈N₂O and a molecular weight of 112.13 g/mol. Its molecular structure consists of a five-membered isoxazole ring bearing a primary amino group at the 3-position and two methyl substituents at the 4- and 5-positions. This specific substitution pattern—combining an electron-rich, metabolically stable isoxazole core with a free primary amine—confers exceptional utility as a versatile building block in medicinal chemistry, agrochemical development, and materials science.

As a white to yellowish crystalline solid with a melting point of 115–117°C and a predicted boiling point of 250.0±35.0°C at 760 mmHg, 4,5-dimethylisoxazol-3-amine is insoluble in water but soluble in organic solvents such as ethanol and ether. The isoxazole scaffold is recognized as a privileged structure in drug discovery, present in numerous bioactive molecules, while the free primary amine enables facile derivatization via amide coupling, urea formation, reductive amination, sulfonylation, and imine formation. Its rigid, electron-rich ring system enhances metabolic stability and target binding affinity, making it an invaluable intermediate for the synthesis of selective kinase inhibitors, BRD4 inhibitors, endothelin receptor antagonists, and agrochemical actives. Based on its chemical characteristics and industrial significance, this article systematically analyzes the key properties, core application areas, global market structure, regional dynamics, regulatory landscape, and future outlook of this strategically important heterocyclic building block.

Key Properties and Reactivity Profile

4,5-Dimethylisoxazol-3-amine (CAS# 13999-39-8) is a substituted isoxazole whose value derives from the combination of a privileged heterocyclic scaffold and a reactive primary amine.

Key physicochemical parameters include:

• Molecular Formula: C₅H₈N₂O
• Molecular Weight: 112.13 g/mol
• CAS Number: 13999-39-8
• EINECS Number: 237-802-7
• MDL Number: MFCD03411577
• Appearance: White to yellowish to brown solid/crystalline powder
• Melting Point: 115–117°C
• Boiling Point: 250.0±35.0°C at 760 mmHg (predicted)
• Density: 1.118±0.06 g/cm³ (predicted)
• pKa: 2.26±0.10 (predicted)
• XLogP3: 0.8
• Topological Polar Surface Area: 52 Ų
• SMILES: CC1=C(ON=C1N)C
• InChIKey: VPANVNSDJSUFEF-UHFFFAOYSA-N
• Storage: Keep in dark place, sealed in dry, room temperature
• GHS Classification: Warning; H302 (Harmful if swallowed)
• WGK Germany: 3 (high hazard to water)
• HS Code: 2934999090

The compound’s reactivity is defined by its primary amine group, which can undergo a wide range of transformations: formation of amides via acylation reactions, creation of sulfonamides through reaction with sulfonyl chlorides, and imine formation with aldehydes and ketones. The isoxazole ring is electron-rich and confers metabolic stability, while the methyl groups at positions 4 and 5 provide steric and electronic modulation of the scaffold’s properties.

Core Application Fields and Demand

Market demand for 4,5-dimethylisoxazol-3-amine (CAS# 13999-39-8) is concentrated in three primary sectors: pharmaceutical R&D and drug discovery (approximately 55–65% of global consumption), agrochemical development (approximately 20–25%), and materials science and specialty chemical applications (approximately 10–15%). Its privileged isoxazole scaffold and versatile primary amine functionality serve as the core drivers of sustained demand growth.

In pharmaceutical R&D and drug discovery, 4,5-dimethylisoxazol-3-amine is a versatile heterocyclic building block widely used in medicinal chemistry. The isoxazole core is a privileged scaffold present in many bioactive molecules, and the free primary amine enables facile derivatization. The compound serves as a key precursor for the synthesis of selective kinase inhibitors targeting cancer, inflammation, and autoimmune diseases, including p38 MAPK, PI3K, and CDK inhibitors. Recent studies have highlighted the compound’s potential in synthesizing BRD4 inhibitors, which are promising candidates for cancer therapy. Derivatives of 4-(3-(3,5-dimethylisoxazol-4-yl)benzyl)phthalazin-1(2H)-one were evaluated for their inhibitory effects against BRD4, with one derivative demonstrating an IC₅₀ value of 0.544 μM against the BD1 domain. The compound is also used in the preparation of selective ETA receptor antagonists, antiviral agents, antibacterial agents, and antifungal agents. In drug development, the isoxazole ring enhances metabolic stability and target binding affinity, making this building block particularly valuable for optimizing drug-like properties. The compound has also been useful in developing drugs targeting neurological disorders.

In agrochemical development, 4,5-dimethylisoxazol-3-amine is utilized in the formulation of agrochemicals, including herbicides and fungicides. Its role in developing environmentally friendly solutions is crucial for sustainable agriculture. Herbicides based on this scaffold are effective against a range of weeds while minimizing environmental impact, and fungicides provide protection against fungal diseases in crops. The compound is also used as an insecticide to control agricultural pests such as cotton aphid, tomato spotted loon, and pear small green inchworm.

In materials science and specialty chemicals, the compound is explored for its potential to create novel materials with specific electronic or optical properties, which can lead to advancements in sensor technology and other applications. It is also employed as a reagent in analytical chemistry techniques for the detection and quantification of other chemical substances within complex mixtures. Additionally, the compound is used to form 4,5-dimethylisoxazolones and other heterocycles.

In organic synthesis and research, 4,5-dimethylisoxazol-3-amine serves as a key intermediate and building block for the synthesis of diverse organic compounds, primarily for research and development purposes in the creation of complex organic molecules.

Major Market Participants

The global supply system for 4,5-dimethylisoxazol-3-amine (CAS# 13999-39-8) features a pattern of “specialized research chemical suppliers, multinational distributors, and Chinese manufacturers serving distinct market segments.” As a specialized heterocyclic building block rather than a bulk commodity, the market is characterized by a moderate number of suppliers catering to pharmaceutical R&D, agrochemical development, and academic research.

In the global research and high-purity segment, key international suppliers include Fluorochem, offering the compound at ≥95% purity; Aladdin Scientific, offering ≥97% purity; Biosynth, providing reactive chemical intermediates; BOC Sciences, offering building blocks for biologically active compounds; and BenchChem, supplying research-grade material. Other suppliers include Indofine Chemical Company, Chem-Impex, and Matrix Scientific. These suppliers serve the pharmaceutical, biotechnology, and academic research communities with products that meet rigorous quality specifications, typically at 95–98% purity.

In the industrial and large-scale production segment, Chinese manufacturers have emerged as a dominant force in the global supply chain. Numerous chemical companies in China operate production facilities for 4,5-dimethylisoxazol-3-amine, leveraging cost advantages and established supply chains to serve both domestic and international markets. Suppliers are concentrated in major chemical manufacturing regions including Zhejiang, Hubei, Henan, Hebei, and Shaanxi. Key Chinese suppliers include manufacturers offering the compound at 98–99% purity in packaging sizes ranging from grams to kilograms. XinChem is a reliable manufacturer and supplier of high-purity 4,5-dimethylisoxazol-3-amine from China, offering custom synthesis and contract manufacturing with flexible scaling from R&D to commercial tons.

Regional Market Dynamics

The global 4,5-dimethylisoxazol-3-amine market exhibits distinct regional characteristics, with production concentrated in Asia-Pacific (particularly China) and consumption distributed across North America, Europe, and the Asia-Pacific region, aligned with the pharmaceutical, agrochemical, and materials science industries in these regions.

The Asia-Pacific region has emerged as a significant production hub for 4,5-dimethylisoxazol-3-amine, with China hosting numerous manufacturers and suppliers. The region’s competitive advantages include lower production costs, established chemical infrastructure, and proximity to rapidly growing pharmaceutical and agrochemical industries. Chinese suppliers offer the compound at various purity grades (typically 95–99%) and packaging options, serving both domestic and export markets. The growing pharmaceutical R&D and agrochemical sectors in China, India, Japan, and South Korea continue to drive regional consumption growth. Production capacity from key Chinese manufacturers is estimated at approximately 100 kg/month.

North America remains a key market for high-purity and research-grade 4,5-dimethylisoxazol-3-amine, driven by demand from the pharmaceutical industry, biotechnology companies, and academic research institutions. The United States hosts numerous research organizations, pharmaceutical companies, and agrochemical developers that require high-quality heterocyclic building blocks for drug discovery and development. The region’s well-established regulatory framework and emphasis on product quality support demand for high-grade research chemicals and pharmaceutical intermediates.

Europe is characterized by stringent regulatory requirements and a strong focus on quality and sustainability in pharmaceutical and chemical research. European pharmaceutical companies, agrochemical developers, and research institutions demand high-purity heterocyclic building blocks with comprehensive documentation. Suppliers such as Fluorochem (UK) serve the European research community with in-stock availability.

Japan represents a specialized market where the compound is supplied by distributors such as Fujifilm Wako Pure Chemical.

Regulatory and Safety Considerations

As a research chemical, pharmaceutical intermediate, and agrochemical building block, 4,5-dimethylisoxazol-3-amine (CAS# 13999-39-8) is subject to regulatory oversight in major global economies. Compliance with relevant regulations is essential for market access and trade.

In the United States, 4,5-dimethylisoxazol-3-amine is intended for research and development use only and is not intended for therapeutic, food, cosmetic, or consumer applications unless explicitly stated otherwise. The compound is not a controlled substance.

In the European Union, the compound must comply with REACH registration requirements for import and use. Manufacturers and suppliers must provide comprehensive Safety Data Sheets (SDS) and maintain appropriate documentation.

GHS classification and handling: 4,5-Dimethylisoxazol-3-amine is classified with the signal word “Warning”. Hazard statements include H302 (Harmful if swallowed). Precautionary statements include P264, P270, P301+P312, P330, and P501. The compound is classified as Acute Tox. 4 Oral. The WGK Germany classification is 3 (high hazard to water). The compound should be stored in a dark place, sealed in dry conditions at room temperature, and is classified as a combustible solid (storage class 11). Personal protective equipment including lab gloves, safety glasses, or face shields should be worn during handling, and good ventilation conditions should be maintained.

For international transport, 4,5-dimethylisoxazol-3-amine is classified under HS Code 2934999090. Proper packaging, labeling, and documentation are required for international shipping in compliance with the International Maritime Dangerous Goods Code (IMDG Code) and other transport regulations.

Future Outlook

The market outlook for 4,5-dimethylisoxazol-3-amine is positive, supported by several key growth drivers across its major application segments. While the compound remains a relatively specialized heterocyclic building block, its privileged scaffold and versatile reactivity position it for steady growth in the coming years.

Key growth drivers include:

1. Expansion of targeted cancer therapy R&D: The development of BRD4 inhibitors and selective kinase inhibitors (p38 MAPK, PI3K, CDK) drives demand for this key isoxazole building block.
2. Growth in pharmaceutical R&D: Increasing investment in drug discovery and development, particularly in oncology, inflammation, autoimmune diseases, and neurological disorders, supports demand for versatile heterocyclic building blocks.
3. Expansion of agrochemical development: The growing global demand for novel, environmentally friendly herbicides and fungicides drives consumption of the compound as a precursor for crop protection agents.
4. Privileged scaffold status: The isoxazole core is increasingly recognized as a privileged scaffold in medicinal chemistry, enhancing metabolic stability and target binding affinity.
5. Increasing focus on sustainable agriculture: The compound’s role in developing environmentally friendly solutions for crop protection aligns with global trends toward sustainable agriculture.

Challenges and considerations:

• Regulatory compliance: Increasingly stringent pharmaceutical, agrochemical, and chemical regulations may require ongoing investment in quality systems and documentation.
• Competition from alternative building blocks: The market faces competition from other isoxazole derivatives and heterocyclic building blocks with similar reactivity profiles.
• Limited scale: As a relatively specialized compound, the market for 4,5-dimethylisoxazol-3-amine is smaller than that of commodity chemicals.
• Positional isomer differentiation: The specific 3-amino-4,5-dimethyl substitution pattern must be carefully distinguished from positional isomers such as 3,4-dimethylisoxazol-5-amine.

To succeed in this evolving market landscape, suppliers must focus on product quality (particularly purity and batch-to-batch consistency), supply chain reliability, regulatory compliance, and responsive customer service. Companies that can offer high-purity products, flexible packaging options, and technical support for pharmaceutical, agrochemical, and materials science applications will be well-positioned to capture growing demand.

Shanghai XinChem Co., Ltd. (XinChem)

As a world-leading supplier of organic chemicals and heterocyclic building blocks, Shanghai XinChem Co., Ltd. (XinChem) is dedicated to meeting the innovative needs of the pharmaceutical, agrochemical, materials science, and fine chemical industries. Leveraging extensive experience and advanced manufacturing capabilities, XinChem provides high-quality 4,5-Dimethylisoxazol-3-amine (CAS# 13999-39-8) to customers worldwide. As a trusted manufacturer and supplier based in China, XinChem combines competitive pricing, reliable supply, and exceptional service to establish itself as a preferred partner for research institutions, pharmaceutical companies, and industrial manufacturers seeking this versatile isoxazole building block.

1. Technical Advantages

Advanced Synthesis and Purification Processes
XinChem utilizes state-of-the-art manufacturing facilities and rigorous quality control measures to ensure the purity, consistency, and safety of its 4,5-dimethylisoxazol-3-amine products. The production process incorporates established synthetic routes—including the isoxazole method (reaction of 2-methylpyridine with ammonia to generate 3-amino-2-methylpyridine, followed by condensation with formaldehyde) and other optimized synthetic strategies—enabling the delivery of products with purity ≥98% to ≥99% to meet diverse application requirements. Strict process control ensures consistent product quality, minimal impurities, and batch-to-batch reproducibility, providing customers with reliable performance in pharmaceutical synthesis, agrochemical development, and materials science applications.

Full-Chain Quality Control
The production process strictly adheres to international quality standards, with comprehensive quality control covering raw material sourcing, in-process monitoring, and finished product testing. Each batch is accompanied by a detailed Certificate of Analysis (COA) documenting physical and chemical properties, purity data (HPLC/GC), melting point, and impurity profiles. This commitment to quality ensures that XinChem’s 4,5-dimethylisoxazol-3-amine meets the stringent requirements of pharmaceutical R&D, agrochemical development, and research applications.

2. Product Advantages

High Purity and Consistent Quality
XinChem offers 4,5-dimethylisoxazol-3-amine with purity ≥98% to ≥99% (HPLC/GC), ensuring optimal performance in pharmaceutical synthesis, agrochemical development, and materials science applications. The product’s high purity minimizes the risk of unwanted side reactions and impurities, making it suitable for demanding applications in drug discovery, crop protection, and functional materials.

Comprehensive Specifications
Key specifications include:

• Molecular Formula: C₅H₈N₂O
• Molecular Weight: 112.13 g/mol
• CAS Number: 13999-39-8
• Synonyms: 3-Amino-4,5-dimethylisoxazole; 4,5-dimethyl-1,2-oxazol-3-amine; 4,5-dimethyl-3-isoxazolamine
• MDL Number: MFCD03411577
• Appearance: White to yellowish crystalline powder
• Purity: ≥98% to ≥99% (HPLC/GC)
• Melting Point: 115–117°C
• Storage: Keep in dark place, sealed in dry, room temperature

Flexible Packaging Solutions
XinChem provides a range of packaging options to accommodate diverse customer needs, from laboratory-scale quantities (grams) to industrial-scale packaging (kilograms) and bulk shipments. Customized packaging solutions are available upon request, ensuring safe handling, storage, and transportation.

3. Application Fields

As a versatile privileged heterocyclic building block, 4,5-Dimethylisoxazol-3-amine (CAS# 13999-39-8) exhibits wide application value across multiple industries:

Pharmaceutical R&D and Drug Discovery:

• Key precursor for selective kinase inhibitors targeting cancer, inflammation, and autoimmune diseases (p38 MAPK, PI3K, CDK inhibitors)
• Building block for BRD4 inhibitors for cancer therapy
• Intermediate for selective ETA receptor antagonists
• Precursor for antiviral, antibacterial, and antifungal agents
• Building block for drugs targeting neurological disorders

Agrochemical Development:

• Precursor for herbicides and fungicides
• Insecticide for agricultural pest control

Materials Science and Specialty Chemicals:

• Building block for novel materials with tailored electronic or optical properties
• Reagent for analytical chemistry techniques
• Precursor for 4,5-dimethylisoxazolones and other heterocycles

Organic Synthesis and Research:

• Versatile building block for diverse organic compounds
• Intermediate for complex organic molecule synthesis

4. Service Support

Technical Expertise and Customized Solutions
XinChem’s team of experienced chemists and application engineers provides full technical support throughout the customer journey—from product selection and specification development to application guidance and troubleshooting. Whether customers require optimization of synthetic routes, guidance on derivatization strategies, or assistance with regulatory documentation, XinChem’s technical experts are ready to help. Custom synthesis and contract manufacturing with flexible scaling from R&D to commercial tons are available upon request.

Global Logistics and Reliable Supply
With established supply chains serving markets across Europe, North America, Asia-Pacific, and beyond, XinChem ensures timely delivery and consistent product availability. The company’s logistics team manages all aspects of international shipping, including customs clearance and documentation.

Regulatory Support
XinChem provides comprehensive documentation to support regulatory compliance, including Safety Data Sheets (SDS), Certificates of Analysis (COA), and other required certificates. The company stays current with evolving regulatory requirements in major markets, including REACH, TSCA, and other regional regulations, helping customers navigate the complexities of global trade.

5. Reasons to Choose XinChem

• Professionalism: Extensive experience and deep expertise in heterocyclic building block synthesis and supply.
• Quality: Rigorous quality control, high purity (≥98% to ≥99%), and adherence to international standards.
• Reliability: Stable supply, competitive pricing, and timely delivery.
• Flexibility: Customized solutions to meet diverse customer needs, including custom synthesis and packaging.
• Service: Responsive technical support and comprehensive documentation.

Contact us today to start your partnership with XinChem!

Website: www.xinchem.com

Email: sales1@xinchem.com

WhatsApp: +86 18049800532