Reactivity of α-arylidene benzoheteracyclanone dibromides toward azide ion: an effective approach to 3-(α-substituted-benzyl)chromones and -1-thiochromones
dibromides of 3-arylidenechromanones and -1-thiochromanones with sodium azide resulted in the formation of 3-(α-azidobenzyl)chromones and -1-thiochromones whereas dibromides having no antiperiplanar vicinal hydrogen in the ring such as flavanone, 1-thioflavanone and benzosuberone derivatives afforded only the parent enones by bromine elimination. Evidence supported the intermediacy of 3-(α-bromobenzyl)chromones
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
Electrolytic Partial Fluorination of Organic Compounds. 55.<sup>1</sup> Highly Regio- and Stereoselective Anodic Monofluorination of 2,3-Dihydrochroman-4-one and Chromone Derivatives
作者:Kamal M. Dawood、Toshio Fuchigami
DOI:10.1021/jo0105437
日期:2001.11.1
alpha to the oxygen atom of the (E)-3-benzylidene-2,3-dihydrochroman-4-one derivatives was successfully carried out to provide the corresponding 2-fluorochromanones selectively. This is the first regioselective electrochemical fluorination of fused-type, oxygen-containing heterocyclic compounds. Anodic fluorination of a chromone derivative also gave a similar fluorinated chromanone stereoselectively.
Synthesis of Pyrazoles by Treatment of 3-Benzylchromones, 3-Benzylflavones and Their 4-Thio Analogues with Hydrazine
作者:Albert Lévai、Artur M. S. Silva、José A. S. Cavaleiro、Ibon Alkorta、José Elguero、József Jekő
DOI:10.1002/ejoc.200600043
日期:2006.6
The synthesis of pyrazoles 13–24 has been accomplished by treatment of 3-benzylchromones 1–5, 3-benzylflavones 6–12 and their 4-thioanalogues 25–29 with hydrazine hydrate in hot pyridine. A plausible reaction mechanism for the formation of pyrazoles 13–24 is discussed. A 1H NMR study in [D6]DMSO allowed the presence of both pyrazole annular tautomers to be observed, due to the presence of intramolecular
New Convenient Synthesis of Homoisoflavanones and (±)‐Di‐O‐methyldihydroeucomin
作者:B. Serge Kirkiacharian、Michel Gomis
DOI:10.1081/scc-200049789
日期:2005.3
Upon reaction of 1-(2-hydroxyphenyl)-3-phenylpropane-1-ones (2'-hydroxydihydrochalcones) with dimethylaminodimethoxymethane in boiling toluene, the corresponding 3-benzylchromones are obtained in excellent yields. These latter lead to 3-benzylchroman-4-ones (bomoisoflavanones) by catalytic hydrogenetion. These reactions were applied to the synthesis of (+/-)-3-benzylchroman-4-one and (+/-)-3(4-methoxybenzyl)-5,7-dimethoxychroman-4-one, (+/-)-di-O-methyldihydroeucomin.