Résumé Organocatalyst trityl chloride (Ph3CCl), by in situ formation of trityl carbocation with inherent instability, efficiently promotes the cross-aldol condensation reaction between cycloalkanones and arylaldehydes in solvent-free and homogeneous media to afford α,α′-bis(arylidene)cycloalkanones in high yields. Moreover, an attractive and plausible mechanism based on observations and the literature is proposed for the reaction.
Sequential 1,4‐/1,2‐Addition of Lithium(trimethylsilyl)diazomethane onto Cyclic Enones to Induce C−C Fragmentation and N−Li Insertion
作者:Matthew J. O'Connor、Chunrui Sun、Xinyu Guan、Venkata R. Sabbasani、Daesung Lee
DOI:10.1002/anie.201510152
日期:2016.2.5
α,β‐Unsaturated ketones generally undergo addition reactions with nucleophiles with a preference for either 1,2‐ or 1,4‐addition, but rarely both. However, the right combination of reagents allows for consecutive 1,4‐ and 1,2‐additions to occur: Cyclic α,β‐unsaturated ketones undergo double additions with lithium(trimethylsilyl)diazomethane, effectively generating various molecular frameworks with
The planar chiral 2‐phospha[3]ferrocenophane I has been shown to be the first efficient nucleophilic organocatalyst for the enantioselective synthesis of cyclopentenylphosphonates, through [3+2] cyclizations between diethyl allenylphosphonate and α,β‐unsaturated ketones. The same catalyst has also been applied to the highly enantioselective [3+2] cyclizations of allenic esters with dibenzylideneacetone
Synthesis and biological evaluation of new curcumin analogues as antioxidant and antitumor agents: Molecular modeling study
作者:Said M. Bayomi、Hassan A. El-Kashef、Mahmoud B. El-Ashmawy、Magda N.A. Nasr、Magda A. El-Sherbeny、Naglaa I. Abdel-Aziz、Magda A.-A. El-Sayed、Ghada M. Suddek、Shahenda M. El-Messery、Mariam A. Ghaly
DOI:10.1016/j.ejmech.2015.07.014
日期:2015.8
New curcuminanalogues have been synthesized and their antioxidant activities were investigated by measuring their free radical scavenging capacities. The in vitro and in vivo antitumor activities of the synthesized compounds on Ehrlich ascites carcinoma (EAC) cell line were evaluated. 4-(4-Chlorophenyl)-2-(5-ethyl-7-(4-methoxybenzylidene)-3-(4-methoxyphenyl)-3,3a,4,5,6,7-hexahydro-2H-pyrazolo[4,3-c]
A new and economical synthesis of α, α′-bis(substituted-benzylidene)cycloalkanones has been achieved by the reaction of cycloalkanones with different aromatic aldehydes using nano-TiO2/acetic acid as a catalyst in ethanol under reflux conditions with excellent yields. Five new products and three new single crystal structures are reported.