Absorption and Fluorescent Studies of 3-Hydroxychromones

Abstract

The synthesis and spectral studies of variously substituted 3-hydroxychromones have been carried out. A key relationship between the structural motif of synthesized 3-hydroxychromones (3-HCs) and their fluorescent properties was found. The chromones substituted with electron-donating group at 4'-position expressed the red shift of the N(*) and T(*) band and also exhibited the increased fluorescent intensity ratio while the chromones with electron-withdrawing group showed the blue shift of the N(*) and T(*) band. Therefore, these 3-HCs may behave as the possible fluorescent probes.

Recent advances in the synthesis of 4H-chromen-4-ones (2012 − 2021)

“…Synthesis of 2,3-disubstituted 4H-chromen-4-ones 5.1 Cyclization of 2 0 -hydroxychalcones A well-established strategy for the synthesis of 2-(hetero)aryl-3-hydroxy-4H-chromen-4-ones consists of the cyclization of 1-(2-hydroxyaryl)-3-[(hetero)aryl]prop-2-en-1-ones in alkaline hydrogen peroxide, known as Algar-Flynn-Oyamada (AFO) protocol. Sodium and potassium hydroxides are the most common bases applied and the reaction usually proceeds at ice cold conditions, using methanol 83,[357][358][359][360][361][362][363] or ethanol 77,82,[364][365][366][367] as solvents. The resulting suspensions had to be treated under acidic conditions to recover the desired 2-aryl-3-hydroxy-4H-chromen-4-ones.…”