Epoxidation of homoisoflavones

Abstract

A comparative study of the epoxidation of homoisoflavones (3‐benzyl‐4‐chromones) 1–4 has been performed by various oxidizing agents, víz. Epoxidation with isolated dimethyldioxirane (Method A), with alkaline hydrogen peroxide (Method B), and with sodium hypochlorite (Method C) to obtain the epoxides 4–8. Compounds 2 and 3 have also been oxidized with a combination of dimethyldioxirane and Jacobsen's Mn(III)salen catalysts (R,R)‐11 and (S,S)‐11 to afford 3‐benzoyl‐4‐chromones 9 and 10. Structures of all new compounds have been elucidated by microanalyses, ir and nmr spectroscopic measurements.

4‐Aryl‐2‐ferrocenyl‐ and 2‐Aryl‐4‐ferrocenyl‐2,3‐dihydro‐1,5‐benzothiazepines with Potentially Biological Activities: Synthesis, Characterization, X‐ray Diffraction Studies

“…The 1,5-benzothiazepine derivatives are of particular interest in lead discovery, because they have been found to be active against different families of targets [17]. For example, the 1,5-benzothiazepine moiety represents a privileged class of pharmacophores, because compounds bearing this structural unit possess a broad spectrum of biological activities as anticonvulsants [18], Ca 2+ channel antagonists [19], fungicidal and anti-HIV agents [20], squalene synthase inhibitors [21], V2 arginine vasopressin receptor antagonists, and so on [19,22].…”

Regioselective epoxidation of 3‐(3‐Oxo‐3‐arylpropenyl)chromen‐4‐ones by dimethyldioxirane

“…To our knowledge, epoxidation of these compounds with two sites of epoxidation has not yet been published. For this reason, it appeared expedient to investigate their epoxidation and to search for oxidation method(s) capable of their regioselective epoxidation without decomposition and the formation of by-product(s).The isolated dimethyldioxirane (DMD) [8] was found to be the oxidant of choice both for the epoxidation of various chromone derivatives [9][10][11][12][13][14] and α,β-unsaturated ketones [15][16][17][18][19][20][21][22]. As far as the utility of the dimethyldioxirane is concerned, the 3-(3-oxo-3-arylpropenyl)chromen-4-ones are especially challenging compounds since they possess two electron deficient olefinic double bonds.…”

Regioselective Epoxidation of 3‐(3‐Oxo‐3‐arylpropenyl)chromen‐4‐ones by Dimethyldioxirane.

“…The isolated dimethyldioxirane (DMD) [8] was found to be the oxidant of choice both for the epoxidation of various chromone derivatives [9][10][11][12][13][14] and α,β-unsaturated ketones [15][16][17][18][19][20][21][22]. As far as the utility of the dimethyldioxirane is concerned, the 3-(3-oxo-3-arylpropenyl)chromen-4-ones are especially challenging compounds since they possess two electron deficient olefinic double bonds.…”