1. Product Overview
Ethyl 5-amino-1-methyl-1H-pyrazole-4-carboxylate (CAS: 1267231-69-5) is a functionalized pyrazole ester with the molecular formula C₇H₁₁N₃O₂ and a molecular weight of 169.18 g/mol. This compound features a 1H-pyrazole ring bearing a methyl group on the ring nitrogen (N1), an amino group at the 5-position, and an ethyl carboxylate at the 4-position. The pyrazole core is a privileged heterocycle in medicinal and agrochemical chemistry, and this particular substitution pattern provides orthogonal reactivity: the 5-amino group can be acylated, condensed, or diazotized, while the ethyl ester at C4 is amenable to hydrolysis, reduction, or amidation. The N-methylation improves lipophilicity and removes an H-bond donor, making it a valuable building block for SAR studies in drug and crop-protection agent discovery.
2. Key Features and Advantages
• Multifunctional Pyrazole Scaffold: Combines 5-amino, 4-ester, and N1-methyl groups on the pyrazole ring, enabling sequential and selective derivatization for library synthesis.
• Pharmaceutical & Agrochemical Relevance: Pyrazole-4-carboxylates with a 5-amino group are key intermediates for cephalosporin analogues, kinase inhibitor precursors, and pyrazole-carboxamide insecticides.
• N-Methyl Advantage: The 1-methyl substitution eliminates pyrazole N–H tautomerism, simplifies regiochemistry, and enhances membrane permeability in derived bioactive molecules.
• High Purity Grade: Typically supplied at ≥98% purity (HPLC), suitable for sensitive medicinal chemistry and process R&D.
• Stable Solid Form: White to off-white solid with good handling properties and stability under recommended cool, dry storage.
• Scalable Availability: Available from 1 g lab packs up to kilogram scale for route scouting and pilot synthesis.
3. Main Applications
3.1 Pharmaceutical Intermediate
This compound is widely used as a building block in pharmaceutical research:
• Kinase Inhibitor Precursors: The 5-amino-4-ester pyrazole scaffold is employed to construct ATP-competitive kinase inhibitors (e.g., CDK, JAK, Aurora kinase programmes) after cyclocondensation or amide formation.
• Heterocyclic Fusion: The 5-amino and 4-ester groups can undergo intramolecular cyclization to form fused pyrazolo[3,4-d]pyrimidines, pyrazolopyrimidines, and related purine bioisosteres for anticancer and antiviral drug discovery.
• β-Lactam Analogues: Pyrazole carboxylates serve as side-chain or core mimics in cephalosporin and carbapenem antibiotic research.
3.2 Agrochemical Research
Pyrazole carboxamides and esters are foundational in modern crop protection:
• Insecticide Development: The 5-amino-1-methylpyrazole-4-carboxylate motif appears in scaffolds related to anthranilic diamide insecticides and neonicotinoid analogues.
• Fungicide & Herbicide Intermediates: Used to synthesize pyrazole-amide fungicides (e.g., derivatives of fluxapyroxad-type SDHI inhibitors) and selective herbicides via condensation of the 5-amino group with aroyl chlorides or isocyanates.
3.3 Organic Synthesis & Library Generation
• The ethyl ester can be hydrolyzed to the carboxylic acid for amide coupling or reduced to the hydroxymethyl group.
• The 5-amino group participates in Schiff-base formation, acylation, and diazotization leading to halogenation or azide chemistry.
• Ideal for parallel synthesis of focused libraries to explore structure–activity relationships around the pyrazole core.
4. Technical Specifications
5. Storage and Handling
Storage Conditions
• Store in a cool, dry place at 2–8 °C in a tightly sealed container.
• Protect from light; use amber vials or foil wrapping.
• Keep away from strong acids (the 5-amino group can protonate), strong oxidizers, and moisture (ester hydrolysis risk over long term).
• For long-term storage (>6 months), keep under inert atmosphere (argon or nitrogen) to preserve the amino group integrity.
Handling Precautions
• Handle in a well-ventilated area or fume hood to avoid inhalation of fine dust.
• Avoid contact with skin, eyes, and clothing.
• Use appropriate PPE as detailed in Section 6.
6. Safety Overview
Hazard Identification
• Not classified as a GHS hazardous substance under standard regulations based on available data; intended strictly for industrial and scientific research use.
• May cause mild irritation to eyes, skin, and respiratory tract upon contact or dust inhalation.
• The 5-amino group can form aerosols or fine dust; prolonged or repeated exposure should be avoided.
• Not for human or veterinary therapeutic use, not for food, feed, or cosmetic application.
First Aid Measures
• Inhalation: Move to fresh air. Seek medical attention if irritation or breathing difficulty persists.
• Skin Contact: Remove contaminated clothing. Rinse affected area thoroughly with soap and water.
• Eye Contact: Rinse immediately with plenty of running water for at least 15 minutes, holding eyelids open. Consult an ophthalmologist if irritation continues.
• Ingestion: Rinse mouth. Do NOT induce vomiting. Seek immediate medical attention.
Personal Protective Equipment (PPE)
• Eye/Face Protection: Safety goggles or face shield.
• Hand Protection: Nitrile chemical-resistant gloves.
• Body Protection: Lab coat, long sleeves, closed-toe shoes.
• Respiratory Protection: NIOSH-approved dust mask or particulate respirator if handling generates airborne particles.
Disposal Considerations
• Dispose of as hazardous chemical waste per local, regional, and national regulations.
• Do not discard in drains or release into the environment.
• Incinerate in a licensed chemical waste facility.
