Fragmentation Study Using H/D Exchange and ESI-MSn to Facilitate Structural Elucidation of Novel Macrocycles
- Detailed fragmentation study of azithromycin aglycone and its derivatives by means of ESI-MSn and H/D exchange – detailed understanding of fragmentation pathways of different 15-membered azalides
- H/D exchange experiments – insight into fragmentation routes of analysed compounds
- Comparison of fragmentation patterns of macrocyclic [M+H]+ ions and sodium adduct ions [M+Na]+ -influence of an alkali metal interacting with the aglycone ring on the product-ion spectra
- The synthesis of new macrolide antibiotics involving structural modifications of azithromycin leads to novel classes of compounds. New chemical series were based on an aglycone ring as a core structure.
- Understanding the fragmentation of the different structural modifications of 15-membered azalides enables easier structure elucidations of newly synthesised compounds, proces impurities, related substances and degradation products.
- Comprehensive fragmentation study on azithromycin and it’s analogues using ESI-MSn and H/D exchange on both [M+H]+ and [M+Na]+ gave insight characteristic fragments.
- Characteristic elimination of sugars from azithromycin in deuterated solvent gave ions at m/z 596, 597 and 598.
- The most intense signal at m/z 596 corresponded to the elimination of cladinose sugar moiety.
- The elimination of desosamine sugar from compound azithromycin gave two ions with signals at m/z 597 and m/z 598.
- Possible structures representing the elimination of sugars from azithromycin in deuterated solvent are given in scheme.