The fragmentation rules for electrospray ionization-collision induced dissociation mass spectrometry (ESI-CID MS) differ greatly from the rules for electron ionization mass spectrometry (EI-MS). With the goal of elucidating the fragmentation pathway of alkali metal-cationic adduct ions of organic molecules in ESI-CID mass spectrometry, dibenzylated and tribenzylated polyphenolic compounds and their selectively deuterated isotopomers have been previously synthesized, and introduced to ESI-CID MS and DFT modeling as a means of investigating this method. In this study, we continue to expand upon the subject by synthesizing the three tetrabenzylated isomers, and their deuterated isotopomers (1), (2), and (3). Starting from the desired trihydroxybenzaldehyde, the starting material is sequentially labelled with D0, D2, D5 and D7 benzyl moieties. A Dakin reaction is implemented to access the final position for benzylation. X-ray crystallography is necessary to confirm monobenzylated and dibenzylated species that would otherwise be ambiguous in NMR spectroscopy. The aim of this study is to further clarify the fragmentation patterns of organic molecules under ESI-CID MS conditions by utilizing these selectively deuterated tetrabenyzlated polyphenolic compounds. Here, we describe the synthetic route for both the non-deuterated and the deuterated version of each isomer, as well as the modeling and fragmentation outcomes.

Synthesis of selectively deuterated tetra(benzyloxy)benzenes for the purpose of elucidating ESI/CID fragmentation pathways

255th National Meeting (2018)

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