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Updated: Jul 16, 2026

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
Published on: February 16, 2020
Reaction dynamics of excited ketoprofen with triethylamine
Hiroyuki Suzuki1, Tadashi Suzuki, Teijiro Ichimura
1Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Ohokayama, Meguro, Tokyo 152-8551, Japan.
Abstract:
The reaction dynamics of ketoprofen (KP) with and without triethylamine (TEA) in methanol both in the ground and the excited states was studied by laser flash photolysis and the pump-probe emission spectroscopy. After the excitation, triplet KP abstracted a hydrogen atom from methanol to form KP ketyl radical (KPH). In the presence of TEA, the acid-base equilibrium state was found to be KP + TEA right arrow over left arrow KP- + TEAH+ in the ground state. The equilibrium constant was determined to be 32 +/- 7. Excited KP- rapidly underwent decarboxylation to form a carbanion resonant with the 3-ethylbenzophenone ketyl biradical anion (3-EBP-), followed by a proton-transfer reaction with TEAH+ to produce the 3-ethylbenzophenone ketyl biradical (3-EBPH). Furthermore, 3-EBPH was found to make a complex with TEA, whose equilibrium constant was obtained to be 18 +/- 2 M(-1). The complex formation ability of 3-EBPH was discussed compared with benzophenone ketyl radical (BPH).
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