H D ISOTOPIC EXCHANGE IN THE FAST-ATOM-BOMBARDMENT OF ECDYSTEROIDS/

Deuterium exchange in a glycerol-O-d(3) matrix affords the number of h ydroxyl groups present in molecules of various types of ecdysteroids i n both positive and negative ionization modes. H/D exchange also allow s the easy distinguishing of isomeric and isobaric compounds. It is sh own that the ecdysteroids under study exchange an additional hydrogen, owing to the presence of an enol form of a C6 keto group, The high ex tent of enolization occurring at the C22 keto functionality was observ ed in the pseudomolecular ion of 22-oxo-20-hydroxyecdysone. (C) 1997 b y John Wiley & Sons, Ltd. No. of Figures:4 No. of Tables:2 No. of Refs :35.