Recognition of Cyclic, Acyclic, Exocyclic and Spiro Acetals and Their Isomers via Structurally Diagnostic Ion/Molecule Reactions with the (CH_(3))_(2)N-C~(+)(velence)O Acylium Ion

摘要

The model acylium ion (CH_(3))_(2)N-C(velence)O~(+) reacts with acyclic acetals in a structurally diagnostic fashion and characteristic reactivities are observed. Acyclic acetals of several types can be therefore distinguished by applying this reaction and the nature and position of their substituents determined. Acyclic acetals can also be distinguished from cyclic acetals and analogue compounds such as diols and their analogues. To exemplify the general application of the reactions with (CH_(3))_(2)N-C(velence)O~(+), and the many sets of isomers within these classes that could be readily recognized and distinguished. Although this study has used volatile model compounds and gas-phase reactions under the low pressure conditions of a tandem mass spectrometer, this approach for structural investigation can also be applied to larger, less volatile molecules using atmospheric pressure ionization techniques such as ESI, DESI, and EASI.