Synthesis of 3-(N-arylcarbamoyl)chromones from 2-hydroxyarylaminoenones and isocyanates

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

“…Few examples of 2-aryl-3-iodo-4H-chromen-4-ones arose from heterocyclization reaction of (E)-3-aryl-3-benzylamino-1-(2-hydroxyaryl) prop-2-en-1-ones in presence of molecular iodine in methanol at room temperature for 16 h. 435 Treating the same precursors with various isocyanates in a minimal amount of DMF or toluene at 110 °C delivered 2-aryl-4-oxo-4H-chromen-3-carboxamides (Scheme 84) 298 and with aryl isothiocyanates in hot DMF yielded 2-aryl-4-oxo-4H-chromen-3thiocarboxamides. 275 Chen et al established a protocol for the synthesis of 2,3-diphenyl-4H-chromen-4-ones involving palladium(II)-catalyzed carbonylative reaction of 1-bromo-2-fluorobenzenes with 2-arylacetophenone in the presence of DPPB and cesium carbonate in DMAc at 140 °C for 40 h, in modest yields.…”

“…296 Catalyst-free C-H acyloxylation of o-hydroxyaryl enaminones with aroyl peroxides in ethanol at room temperature provided 3-acyloxy-4H-chromen-4-ones (Scheme 41) 297 while 4-oxo-4H-chromen-3carboxamides are prepared from the reaction of o-hydroxyaryl enaminones with various isocyanates in a minimal amount of DMF or toluene at 110 °C for 1-8h. 298 4.1.2 Conversion into 4-oxo-chromen-3-carbaldehydes 4-Oxo-4H-chromen-3-carbaldehyde and its derivatives are versatile building blocks for the synthesis of a huge number of heterocyclic compounds. In 2014, Sepay and Dey 299 reviewed the literature covering the previous 5 years on the synthesis and chemical reactivity of 4-oxo-4H-chromen-3-carbaldehyde and the synthetic strategies to prepare this moiety are quite similar to those described on the next decade.…”