IODINE CATALYZED CASCADE SYNTHESIS OF FLAVONE DERIVATIVES FROM 2'-ALLYLOXY-α, β-DIBROMOCHALCONES
作者:BEENA R NAWGHARE、SUNIL V GAIKWAD、ABDUL RAHEEM、PRADEEP D LOKHANDE
DOI:10.4067/s0717-97072014000100009
日期:——
Synthesis of flavones from 2'-allyloxy-α, β-dibromochalcones has been described. The iodine induced oxidative cyclization of 2'-allyloxy-α, β-dibromochalcones results into the formation of 3-bromoflavanones which ultimately gives flavones. Dehydrobromination of 3-bromoflavanone to give flavone is the preferred reaction over dehydrogenation. 6 3-Bromoflavones are used in drugs and for synthesis of alkylated
Unusual Olefinic C–H Functionalization of Simple Chalcones toward Aurones Enabled by the Rational Design of a Function-Integrated Heterogeneous Catalyst
components of the catalyst: (a) a supportedPdcatalyst: a catalyst for the olefinic C–H functionalization of chalcones toward aurones, (b) an Au promoter: an improvement in the catalytic activity by stabilizing Pd(0), (c) a CeO2 support: the inhibition of the 6-endo-trig cyclization utilizing the adsorption of chalcones, and (d) a Pd-on-Au structure: the inhibition of Au-catalyzed flavone synthesis. This catalytic
Selective O-deallylation of dihydropyrazoles by molecular iodine in the presence of active N-allyl and formyl groups
作者:Vivek T. Humne、Kamal Hasanzadeh、Pradeep D. Lokhande
DOI:10.1007/s11164-012-0581-2
日期:2013.2
Selective O-deallylation of dihydropyrazoles has been achieved by use of iodine (10 mol%) in PEG-400 as ecofriendly solvent. Iodine (10 mol%) in dimethyl sulfoxide at 100 °C also afforded O-deallylation with aromatization compatible with highly reactive N-allyl and formyl groups. The function of iodine in the synthesis of substituted pyrazoles under different conditions is described.
Studies in halochalcones and related compounds: synthesis of 3′:5′-dichloro-2′-hydroxychalcones and their derivatives
作者:B.C. Jha、G.C. Amin
DOI:10.1016/0040-4020(58)88044-8
日期:1958.5
The condensation of 3:5-dichloro-2hydroxy acetophenone with various aldehydes afforded chalcones, which were converted into the corresponding 6:8-dichloroflavanones by the action of dilute ethanolic hydrochloric acid. The oxidation of chalcones by means of selenium dioxide and by alkaline hydrogen peroxides gave 6:8-dichloro-flavones and -flavonols respectively. Incidentally, some chalcones from 3
Access to Chromenopyrrole via Tandem [3 + 2] Cycloaddition and Intramolecular C–O Coupling
作者:Bubul Das、Nikita Chakraborty、Hirendra Nath Dhara、Pratip Bhattacharyya、Bhisma K. Patel
DOI:10.1021/acs.joc.3c02479
日期:2024.1.19
A mild and concise method for the synthesis of chromenopyrrole from 2′-hydroxychalcone is devised. The reaction proceeds via an initial [3 + 2] cycloaddition on the C═C bond of 2′-hydroxychalcone and 1,3-dipolarophile, generated in situ by the reaction of ethyl isocyanoacetate and AgOAc. This is then followed by an intramolecular C–O bond formation with the −OH group and C5–H of the in situ generated