Differentiation of anomeric C-glycosides by mass spectrometry using fast atom bombardment, mass-analysed ion kinetic energy and collision-activated dissociation

✍ Scribed by Mohamed Brakta; Brahim Chaguir; Denis Sinou; Joseph Banoub; Michel Becchi

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 858 KB
• Volume: 27
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210270328

✦ Synopsis

Positive-ion fast atom bombardment maw spectrometry appears to be a useful method for the differentiation of anomeric C-glycosides. The mass-analysed ion kinetic energy (MIKE) and collision-activated dissociation (CAD) MIKE spectra of selected positive ions can be used as fingerprints of the a-or /$-anomem. The main fragmentation routes and particularly the formation of the [ M -HI + ion and the [ M + H -PhCH,OH] + ion were traced for each anomer. Compounds 1 4 (Scheme 1) were prepared as described p r e v i ~u s l y . ~~ Compounds 5 and 6 were obtained by hydrogenation of la and 2, respectively, in the presence of RhCI(PPh,), and compounds 7 by reduction of the corresponding benzylated unsaturated compounds29 in the presence of Pd/C followed by acetylation. The products were carefully purified by column chromatography on silica gel.

Ethyl 2-(2',3'-dideoxy-4,6-di-O-benzyl-cr-~-glucopyranosyl-2-nitro-2-carboethoxy acetate (5). [@I;' + 30" (c 1.3, CH,CI,); 'H NMR (300 MHz, CDCI,), 6 1.29 (3H,