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Updated: Oct 10, 2025

Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
Gas-phase fragmentation of protonated 3-phenoxy imidazo[1,2-a] pyridines using tandem mass spectrometry and
Yanchun Guo1, Shigai Li1, Hong Chen1
1College of Chemistry, The Key Laboratory of Chemical Biology and Organic Chemistry of Henan Province, Zhengzhou University, Zhengzhou, China.
Abstract:
Imidazo[1,2-a] pyridine is one of the pharmaceutically important scaffolds and has been widely studied due to its extensive biological activities. In this work, electrospray ionization tandem mass spectrometry (ESI-MS/MS) in positive mode was used to study the gas-phase fragmentation behavior of a series of 3-phenoxy imidazo[1,2-a] pyridines. Proposed fragmentation pathways were supported by ESI-MS/MS data and computational thermochemistry. Homolytic cleavage of the 3-phenoxy C-O bond was the characteristic fragmentation of 3-phenoxy imidazo [1,2-a] pyridines. The eliminations of the one substituted phenoxy radical and CO produced other diagnostic ions for 3-phenoxy imidazo [1,2-a] pyridines, which were useful to identify the 3-phenoxy group and imidazo [1,2-a] pyridine scaffold. The results contribute to the further understanding of the gas-phase fragmentation of 3-phenoxy imidazo [1,2-a] pyridines and the identification of other analogs using tandem mass spectrometry techniques.
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