engleski

Photochemical generation of aza-o-quinone methides

Aza-quinone methides (a-QM) are reactive intermediates, reacting with nucleophiles and various types of dienophiles, applicable in the synthesis of biologically important heterocycles. Due to their importance in synthesis, several methods to generate a-QM have been reported, including photogeneration from o-aminobenzyl alcohol. Although a-QM has been detected by laser flash photolysis (LFP), its trapping by alkenes in [4 + 2] cycloaddition in the acidic solution was hampered, and the composition of the irradiated mixture strongly depended on the solution pH. We conducted a systematic mofication of the structure of a-QM precursors in order to optimize the conditions for their photogeneration and enable trapping by alkenes. The amino group was functionalized by EWG, whereas the alcohol was converted to a better leaving group. The photoreactivity was investigated by irradiation experiments, and the products were isolated and fully characterized. To unravel details about the reaction mechanism, steady-state and time-resolved fluorescence and LFP measurements were conducted.

Photodehydration ; Photoelimination of acetic acid ; Aza-quinone methide

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