Selective formation of a phenathridine derivative by photodegradation of azilsartan. (1st June 2021)

• Record Type: Journal Article
• Authors: Yoshikawa, Takahiro; Hayashi, Naoto; Hatta, Naoya; Yokota, Masayuki
• Is Part Of: Bioorganic & medicinal chemistry letters. Volume 41(2021)
• Publication Date: 2021-06-01
• Subjects: Azilsartan -- Photolysis -- Phenanthridine -- Imidoylnitrene -- Intramolecular cyclization; Bioorganic chemistry -- Periodicals; Pharmaceutical chemistry -- Periodicals; 572
• DOI: 10.1016/j.bmcl.2021.128011
• Languages: English
• ISSNs: 0960-894X

Abstract

Graphical abstract: Highlights: The chemical structure of photodegradation product of azilsartan was determined by alternative synthesis and single-crystal X-ray diffraction. The photodegradation product was a phenanthridine derivative. The photolysis mechanism via an imidoylnitrene intermediate has been proposed. Abstract: Photodegradation of azilsartan produces a phenanthridine derivative, with its molecular structure determined by 1 H and 13 C NMR spectroscopy. This structure is confirmed by single-crystal X-ray diffraction and alternative synthesis. The phenanthridine ring formation is explained through the ring closure of an imidoylnitrene intermediate produced by decarboxylation of the 5-oxo-1, 2, 4-oxadiazole ring (oxadiazolone).