Maleimide – general description and preparation

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General description and preparation of Maleimide:

Maleimide [541-59-3] or 2,5-Pyrroledione is a unsaturated imide which name is a contraction of maleic acid and imide. It is a white crystalline solid with the melting point of 92-93 °C.^[1] Maleimide can be synthesized via thermal decomposition of N-carbamoylmaleimide formed by reaction of maleic anhydride with urea.^[2] In general, maleimides are produced by ring-closure imidation of various maleinamic acids in an organic solvent capable of forming an azeotrope with water in the presence of an acid catalyst and metal-containing compound (zinc acetate) as a promoter.^[3]

Application of Maleimide:

Maleimide is versatile building block in organic synthesis. A special feature of the reactivity of maleimides is their susceptibility to additions across the double bond either by Michael additions or via Diels-Alder reactions. Natural maleimide derivatives (ferinomalein, showdomycin, pencolide, turrapubesin) with the promising biological activities were isolated from bacteria and fungi.^[4] Recently, maleimide, N-ethylmaleimide, N-methylmaleimide and N-phenylmaleimide have attracted the interest due to the cytotoxicity toward tumor cell lines through the inhibition of human topoisomerase II.^[5] Maleimide-mediated methodologies are among the most used in bioconjugation.^[6] Maleimide-functionalised polymers and liposomes exhibit enhanced ability to adhere to mucosal surfaces (mucoadhesion) due to the reactions with thiol-containing mucins.^[7]

Product categorization (Chemical groups):

Main category:

• Carboxylic acid derivatives / Anhydrides / Imides / Hydrazides

Second level:

• Aliphatic compounds

Third level:

• Heterocyclic compounds

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