Maleimide (CAS 541-59-3) | Versatile Chemical Building Block
Product Concept
Maleimide (CAS 541-59-3), a highly reactive five-membered cyclic imide with the molecular formula C₄H₃NO₂, serves as a cornerstone in organic synthesis and bioconjugation chemistry. This white to off-white crystalline solid, with a molecular weight of 97.07 g/mol and melting point of 91-93°C, demonstrates exceptional reactivity towards thiol groups (k = 10³-10⁴ M⁻¹s⁻¹) under physiological conditions. Its unique electronic structure, featuring an electron-deficient double bond, enables diverse chemical transformations, including Michael additions, Diels-Alder reactions, and radical polymerizations. With solubility in common organic solvents (e.g., acetone >200 mg/mL) and moderate water solubility (≈50 mg/mL), maleimide has become indispensable in materials science, pharmaceutical development, and biochemical research.
Technical Specifications
- Molecular Formula: C₄H₃NO₂
- Molecular Weight: 97.07 g/mol
- Appearance: White to off-white crystals
- Purity: ≥99% (HPLC)
- Melting Point: 91-93°C
- Solubility: Acetone (>200 mg/mL), Water (50 mg/mL)
- Storage: 2-8°C under nitrogen atmosphere
Chemical Reactivity
- Thiol Conjugation: Forms stable thioether bonds (pH 6.5-7.5)
- Diels-Alder Reaction: Reacts with dienes at 60-80°C
- Radical Polymerization: Initiates at 70-90°C with AIBN
- Nucleophilic Addition: Reacts with amines at elevated temperatures
Industrial & Research Applications
Bioconjugation
- Antibody-drug conjugate (ADC) development
- Protein labeling and immobilization
- PEGylation of therapeutic proteins
Polymer Chemistry
- Crosslinking agent for rubbers
- Thermoset resin component
- Functional monomer for smart polymers
Organic Synthesis
- Building block for heterocycles
- Intermediate for pharmaceutical synthesis
- Ligand in organometallic catalysis
Synthetic Routes
- Maleic anhydride amination
- Catalytic dehydrogenation of succinimide
- Microwave-assisted synthesis
- Electrochemical oxidation method
Quality Assurance
- HPLC-UV purity analysis (C18 column)
- FTIR for functional group verification
- ¹H/¹³C NMR structural confirmation
- Residual solvent testing (GC-MS)
- Elemental analysis (C, H, N)
Safety & Handling
- Acute Toxicity: LD₅₀ = 245 mg/kg (oral, rat)
- Skin Sensitization: GHS Category 1B
- Proper PPE: Nitrile gloves, chemical goggles
- Storage: Inert atmosphere, desiccated
- Disposal: Incineration with alkaline scrubber