title: An efficient and scalable synthesis of substituted phenanthrenequinones by intramolecular Friedel-Crafts reaction of imidazolides.
abstract: An efficient synthesis of 9,10-phenanthrenequinones is described. The two carbonyl groups were introduced by an orthoselective intermolecular Friedel-Crafts reaction of 3-methoxyphenol with ethyl chlorooxoacetate. The formation of a biaryl bond by Suzuki-Miyaura coupling reaction, followed by the hydrolysis of the ester, gave a biaryloxoacetic acid. Treatment of this acid with CDI gave the corresponding imidazolide. The ring closure to the desired phenanthrenequinone was accomplished by intramolecular Friedel-Crafts reaction of the imidazolide promoted by TiCl(4).
authors: Department of Process Research, Merck Research Laboratories, Merck & Co., Inc., Rahway, New Jersey 07065, USA. naoki_yoshikawa@merck.com
authors: Naoki
authors: N
authors: Yoshikawa
authors: Austin
authors: A
authors: Doyle
authors: Lushi
authors: L
authors: Tan
authors: Jerry A
authors: JA
authors: Murry
authors: Atsushi
authors: A
authors: Akao
authors: Masashi
authors: M
authors: Kawasaki
authors: Kimihiko
authors: K
authors: Sato
mesh_terms: D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D007093:Imidazoles / Q000737:chemistry*; D015394:Molecular Structure; D010616:Phenanthrenes / Q000138:chemical synthesis* / Q000737:chemistry; D011809:Quinones / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D007093:Imidazoles; D010616:Phenanthrenes; D011809:Quinones