Facile Syntheses of 3-Hydroxyflavones

Abstract

Modification of the present synthetic methods led to the syntheses of 3-hydroxyflavones in a shorter reaction time, with simple purification and higher yields. Application of the method provided the syntheses of 3HFs having a hydroxyl group on the phenyl ring (ring B) in one step, which is an improvement compared to the four steps, long reaction time, and low yield using the current method available in the literature.

Excited-state intramolecular proton-transfer reaction demonstrating anti-Kasha behavior

“…The intermediate 3-HTC can be prepared following literature procedures ( Scheme 1A ). 36 We attempted to synthesize 3-HTCA from 3-HTC via the Vilsmeier–Haack reaction, but only obtained a trace amount of 3-HTCA . We then modified the synthetic route for 3-HTCA by using 5-(1,3-dioxolan-2-yl)thiophene-2-carbaldehyde.…”

Rational Design of a Solvatochromic Fluorescent Uracil Analogue with a Dual‐Band Ratiometric Response Based on 3‐Hydroxychromone

“…An important feature of this protocol is the possibility to obtain pure product with minimal manipulation. According to this procedure, 2‐hydroxyacetophonone 7 was treated with thiophene‐aldehydes 8 and 9 in ethanol in the presence of sodium hydroxide with subsequent addition of hydrogen peroxide and acidic work‐up to give 3‐hydroxychromones 2 (TC) and 10 in 50 and 48 % yields, respectively 27. Derivative 4 ( MTC ) was obtained in 97 % yield after methylation of TC by dimethyl sulfate under the phase‐transfer catalysis (PTC) conditions reported previously 28.…”

A flavone-based turn-on fluorescent probe for intracellular cysteine/homocysteine sensing with high selectivity

“…Additionally, these ESIPT-based flavone fluorescent dyes can be excited with visible light [43,44] , which essentially circumvents the photodamage of biological sample in fluorescence detection originating from the illumination of ultraviolet light [32].…”