A New Synthetic Route to Authentic N-Substituted Aminomaleimides

• Published in: Journal of organic chemistry Vol. 70; no. 11; pp. 4553 - 4555
• Main Authors: Conley, N. R, Hung, R. J, Willson, C. G
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 27.05.2005; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Organic; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Organic chemistry; Physical Sciences; Preparations and properties; Science & Technology; 3-CARBOXYACRYLOYLHYDRAZINES; MALEIC HYDRAZIDE; REAGENTS; MALEIMIDES; DERIVATIVES; ISOMALEIMIDES; Imide; Oxygen heterocycle; Chemical synthesis; Nitrogen heterocycle; Organic hydrazine; Furan derivatives
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo048031q

A number of compounds reported in the literature as N-aminomaleimides (2) are, instead, isomeric N-aminoisomaleimides (3). The ubiquity of this mischaracterization and its propagation within the literature are discussed. In addition, the first general synthetic route to aliphatic and aromatic N-substituted aminomaleimides is described. As an illustration, the compound reported to be N-(4-bromophenylamino)maleimide (2b) was prepared and determined to be N-(4-bromophenylamino)isomaleimide (3b). The authentic compound was synthesized by the condensation of 4-bromophenylhydrazine (7b) and the exo-furan/maleic anhydride Diels−Alder adduct (8) in acetic acid to produce the furan-protected aminomaleimide 10b, followed by heating to remove furan through the retro Diels−Alder reaction. The structures of 2b, 3b, and 10b were established unequivocally by X-ray crystallography and other spectroscopic techniques.