Formal Syntheses of (±)-Platensimycin and (±)-Platencin via a Dual-Mode Lewis Acid Induced Cascade Cyclization Approach
作者:Lizhi Zhu、Congshan Zhou、Wei Yang、Shuzhong He、Gui-Juan Cheng、Xinhao Zhang、Chi-Sing Lee
DOI:10.1021/jo401105q
日期:2013.8.16
efficient dual-mode Lewisacid induced Diels–Alder (DA)/carbocyclization cascade cyclization reaction has been developed for construction of the tricycliccore of ent-kaurenoids in one pot with the aid of a theoretical study on the π,σ-Lewis acidities of a variety of Lewisacids. With ZnBr2 as the dual-mode Lewisacid, a series of substituted enones and dienes underwent DA/carbocyclization cascade cyclization
Enantioselective Metal/Organo-Catalyzed Aerobic Oxidative sp<sup>3</sup>C–H Olefination of Tertiary Amines Using Molecular Oxygen as the Sole Oxidant
作者:Gen Zhang、Yunxia Ma、Shoulei Wang、Yaohu Zhang、Rui Wang
DOI:10.1021/ja303333k
日期:2012.8.1
An organocatalysis/copper-catalyzed asymmetric oxidative sp(3) C-H olefination reaction of tertiary amines with olefins usingmolecularoxygen as the sole oxidant under mild conditions was realized for the first time. This novel strategy provides an efficient and environmentally friendly way to access diversify optically active C(1)-alkene tetrahydroisoquinoline derivatives.
In pole position: A simple and efficient approach to spirocyclic γ‐lactam oxindoles by the N‐heterocyclic carbene catalyzed addition of homoenloate equivalents to N‐aryl isatinimines has been developed (see scheme). The use of N‐aryl isatinimines as electrophiles in the NHC‐catalyzed umpolung reaction of α,β‐unsaturated aldehydes is demonstrated for the first time.
VO(acac)(2) catalyzes the oxidation of aldehydes (aromatic, aliphatic, and heterocyclic) to the corresponding acids efficiently and selectively in the presence of H2O2 as an oxidant. This method possesses functional-group compatibility, easy workup procedure, and shorter reaction time. The reaction is highly dependent on the solvent used. Performance of titania-supported VO(acac)(2) in the oxidation of aldehyde was also investigated.
Design, synthesis, and docking studies of novel ofloxacin analogues as antimicrobial agents
A number of novel ofloxacin analogues were synthesized by modifying the carboxylic acid at C-6. To investigate the antimicrobial data on structural basis, in-silico docking studies of the tested compounds into the crystal structure of topoisomerase II using Autodock vina 4.0 program was performed in order to predict the affinity and orientation of the synthesized compounds at the activities. R (2) values show good agreement with predicted binding affinities obtained by molecular docking studies. Also, it is verified by in-vitro antimicrobial screening, where all the compounds were most active against Staphylococcus aureus, Staphylococcus epidermidis and Bacillus subtilis. Among these compounds 3a, 3b, 3f showed good MIC (0.125 mu g/ml).