NMR.-Study of Nitrogen Inversion and Conformation of 1,5-Dihydro-isoalloxazines (‘Reduced Flavin’). Studies in the flavin series, XIX. Communication

✍ Scribed by Ludwig Tauscher; Sandro Ghisla; Peter Hemmerich

• Book ID: 102856416
• Publisher: John Wiley and Sons
• Year: 1973
• Tongue: German
• Weight: 935 KB
• Volume: 56
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19730560209

✦ Synopsis

Abstract

The pyramidal inversion of the N(5)‐centre of several reduced flavins was measured by NMR. The inversion barrier was found to be ∼10 kcal/mol in acetone solutions and to be independent of the size of the N(5) substituent. An increase of the inversion barrier of ∼5 kcal/mol was observed in the case where the N(5) substituent could only be in axial position, and an increase of ∼3.5 kcal/mol was observed for an acyl‐like N(5) substituent. In aqueous solution the inversion barrier increases by ∼3 kcal/mol. The stereochemistry of reduced flavin and its potential relevance in flavin‐dependent biological dehydrogenations is discussed.