1. Pomeranz--Fritsch Synthesis of Isoquinoline: Gas-Phase Collisional Activation Opens Additional Reaction Pathways.
- Author
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Banerjee, Shibdas, Fang Liu, Sanchez, David M., Martínez, Todd J., and Zare, Richard N.
- Subjects
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ISOQUINOLINE , *CHEMICAL reactions , *MASS spectrometry , *GAS phase reactions , *CHEMICAL synthesis , *PROTON exchange membrane fuel cells - Abstract
We have investigated the gas-phase production of isoquinoline by performing collisional activation on benzalaminoacetal, the first intermediate in the classic solution-phase Pomeranz--Fritsch synthesis of isoquinoline. We have elucidated the reaction pathways in the gas phase using tandem mass spectrometry. Unlike the corresponding condensed-phase reaction, where catalytic proton exchange between intermediate(s) and solvent (Brønsted--Lowry base) is known to drive the reaction, the gas-phase reaction follows the "mobile proton model" to form the products via a number of intermediates, some the same as in their condensed-phase counterparts. Energy-resolved mass spectrometry, deuterium labeling experiments, and theoretical calculations (B3LYP/6-31G**) identified 27 different reaction routes in the gas phase, forming a complex interlinked reaction network. The experimental measurements and theoretical calculations confirm the proton hopping onto different basic sites of the precursors and intermediates to transform them ultimately into isoquinoline. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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