Flavones: An important scaffold for medicinal chemistry

A large series of coumarin derivatives (71 compounds) were tested for their monoamine oxidase A and B (MAO-A and MAO-B) inhibitory activity. Most of the compounds acted preferentially on MAO-B with IC(50) values in the micromolar to low-nanomolar range; high inhibitory activities toward MAO-A were also measured for sulfonic acid esters. The most active compound was 7-[(3, 4-difluorobenzyl)oxy]-3,4-dimethylcoumarin, with an IC(50) value toward MAO-B of 1.14 nM. A QSAR study of 7-X-benzyloxy meta-substituted 3,4-dimethylcoumarin derivatives acting on MAO-B yielded good statistical results (q(2)() = 0.72, r(2)() = 0.86), revealing the importance of lipophilic interactions in modulating the inhibition and excluding any dependence on electronic properties. CoMFA was performed on two data sets of MAO-A and MAO-B inhibitors. The GOLPE procedure, with variable selection criteria, was applied to improve the predictivity of the models and to facilitate the graphical interpretation of results.

Inhibition of monoamine oxidases by functionalized coumarin derivatives: biological activities, QSARs, and 3D-QSARs.

Novel CFTR Chloride Channel Activators Identified by Screening of Combinatorial Libraries Based on Flavone and Benzoquinolizinium Lead Compounds

The aryl C-glycoside structure is, among the plenty of biologically active natural products, one of the distinct motifs embedded. Because of the potential bioactivity as well as the synthetic challenges, these structures have attracted considerable interest, and extensive research toward the total synthesis has been performed. This Review focuses on the synthetic strategies and tactics employed in the total synthesis of this class of natural products. The Introduction describes the historical background, structural features, and synthetic problems associated with aryl C-glycoside natural products. Next the Review summarizes the methods for constructing the aryl C-glycoside bonds. Completed total syntheses—and, in some cases, selected examples of incomplete syntheses—of natural aryl C-glycosides are also summarized. Finally described are the strategies for constructing polycyclic structures, which were utilized in the total syntheses.

Total Synthesis of Aryl C-Glycoside Natural Products: Strategies and Tactics

A diverse range of chromen-2-one, chromen-4-one and pyrimidoisoquinolin-4-one derivatives was synthesized and evaluated for inhibitory activity against the DNA repair enzyme DNA-dependent protein kinase (DNA-PK), with a view to elucidating structure−activity relationships for potency and kinase selectivity. DNA-PK inhibitory activity varied widely over the series of compounds evaluated (IC50 values ranged from 0.19 to >10 μM), with excellent activity being observed for the 7,8-benzochromen-4-one and pyrimido[2,1-a]isoquinolin-4-one templates. By contrast, inhibitors based on the benzochromen-2-one (coumarin) or 2-aryl-7,8-benzochromen-4-one (flavone) scaffolds were less potent. Crucially, these studies revealed a very constrained structure−activity relationship at the 2-position of the benzopyranone and pyrimido[2,1-a]isoquinolin-4-one pharmacophore, with only a 2-morpholino or 2-(2‘-methylmorpholino) group being tolerated at this position. More detailed biological studies conducted with the most potent i...

Selective benzopyranone and pyrimido[2,1-a]isoquinolin-4-one inhibitors of DNA-dependent protein kinase: synthesis, structure-activity studies, and radiosensitization of a human tumor cell line in vitro.

Harbhajan S. Mahal

Papers

387. Synthetical experiments in the chromone group. Part XIV. The action of sodamide on 1-acyloxy-2-acetonaphthones

195. Synthetical experiments in the chromone group. Part XVI. Chalkones and flavanones and their oxidation to flavones by means of selenium dioxide

124. Synthetical experiments in the chromone group. Part XIX. A synthesis of genkwanin

344. Synthetical experiments in the chromone group. Part X. Coumarin and chromone formation

154. Some 4-styrylcoumarins