Acetate/Acetic Acid-Assisted One-Pot Synthesis of (diarylmethylene)imidazolone from Amide or Thioamide

With the aim of extending the library of green fluorescent protein chromophore analogs, a facile one-pot synthesis of 5-(diarylmethylene)imidazolones from the corresponding amide or thioamide is described. Isolation of unstable imidate intermediates is not required, thereby circumventing the drawback of previous approaches. A reaction mechanism in which both acetate and acetic acid promote the imidazolone formation is proposed.