Submitted to: Rapid Communications in Mass Spectrometry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/7/2009
Publication Date: 3/3/2009
Citation: Adeuya, A., Price, N.P. 2009. Electron Impact Ion Fragmentation Pathways of Peracetylated C-glycoside Ketones Derived from Cyclic 1,3-diketones. Rapid Communications in Mass Spectrometry. 23:1-10. Interpretive Summary: Sugar "C-glycosides" derived from sugars are a commercially valuable product, but are currently difficult to produce on a large scale. This paper builds on our earlier work showing the preparation of C-glycoside sugars from cyclic diketones using water-based "green" chemistry. Analysis showed that the C-glycosides retained the desirable characteristics of the parent sugars. These results will be valuable to researchers in the US sugar and chemical industry, and may impact the production of bio-based products from agriculturally-derived sugars.
Technical Abstract: Monosaccharide C-glycoside ketones have been prepared by aqueous-based Knoevenagel condensation of isotopically-labeled and unlabeled aldoses with cyclic diketones, 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and 1,3-cyclohexanedione (1,3-CHD). The reaction products and their corresponding acetylated analogs produced characteristic molecular adduct ions by MALDITOF MS. Analysis of the peracetylated species by GCEI MS revealed diagnostic fragment ions that were used to deduce the EI fragmentation pathways and the structure of each C-glycoside ketone. Characteristic gluco- and ribo-specific ions were observed at m/z 350 and m/z 278, respectively. Ions common to both carbohydrate fragmentation pathways were observed at m/z 193 and m/z 169 for the dimedone C-glycoside, and m/z 165 and m/z 141 for the 1,3-CHD C-glycosides. M/z 169 and 141 retain the anomeric carbon (C1) of the original sugar, while m/z 193 and 165 are shown to retain carbons-1, 2, and 3.