ABSTRACT
An efficient E-selective semihydrogenation of internal alkynes was developed under low dihydrogen pressure and low reaction temperature from commercially available reagents: Cl2Pd(PPh3)2, Zn0, and ZnI2. Kinetic studies and control experiments underline the significant role of ZnI2 in this process under H2 atmosphere, establishing that the transformation involves syn-hydrogenation followed by isomerization. This simple and easy-to-handle system provides a route to E-alkenes under mild conditions.
ABSTRACT
In line with a recent study of the pharmacological potential of bioinspired synthetic acetylenic lipids, after identification of the terminal dialkynylcarbinol (DAC) and butadiynyl alkynylcarbinol (BAC) moieties as functional antitumor pharmacophoric units, this work specifically addresses the issue of carbon backbone length. A systematic variation of the aliphatic chain length was thus carried out in both the DAC and BAC series. The critical impact of the length of the lipidic skeleton was first confirmed in the racemic series, with the highest cytotoxic activity observed for C17 to C18 backbones. Enantiomerically enriched samples were prepared by asymmetric synthesis of the optimal C18 DAC and C17 BAC derivatives. Samples with upgraded enantiomeric purity were alternatively produced by enzymatic kinetic resolution. Eutomers possessing the Sâ configuration displayed cytotoxicity IC50 values as low as 15â nm against HCT116 cancer cells, the highest level of activity reached to date in this series.
Subject(s)
Alkynes/pharmacology , Antineoplastic Agents/pharmacology , Fatty Alcohols/pharmacology , Alkynes/chemical synthesis , Alkynes/chemistry , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Fatty Alcohols/chemical synthesis , Fatty Alcohols/chemistry , HCT116 Cells , Humans , Molecular Structure , StereoisomerismABSTRACT
We report a novel series of quinoxaline derivatives from which agents with antiproliferative activity have been identified. Two ethyl 3-(arylethynyl)quinoxaline-2-carboxylates demonstrated substantial antiproliferative activity against both human non-small cell lung carcinoma (A549) and glioblastoma (U87-MG) cell lines. Pyrido[4,3-b]quinoxalin-1(2H)-ones demonstrated poor activity against A549 and U87-MG cell lines. Three of the derivatives in ethyl 3-(arylethynyl)quinoxaline-2-carboxylate series demonstrated substantial antiproliferative activity. The arylethynyl derivative 2a and 2d proved to be the most cytotoxic with an IC50 value of 3.3 µM for both A549 and U87-MG cell lines.
Subject(s)
Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/pharmacology , Carboxylic Acids/chemistry , Drug Design , Quinoxalines/chemical synthesis , Quinoxalines/pharmacology , Antineoplastic Agents/chemistry , Cell Line, Tumor , Cell Proliferation/drug effects , Chemistry Techniques, Synthetic , Humans , Quinoxalines/chemistryABSTRACT
Correction for 'Formal [3+2] cycloaddition of Ugi adducts towards pyrrolines' by Abdelbari Ben Abdessalem et al., Chem. Commun., 2015, 51, 1116-1119.
ABSTRACT
Ugi adducts derived from aromatic aldehydes may be converted to pyrrolines via addition of Michael acceptors under microwave irradiation. The reaction may proceed via unusual formation of azomethine ylides followed by a [3+2] cycloaddition using Michael acceptors.
Subject(s)
Pyrroles/chemical synthesis , Amides/chemistry , Cyclization , Cycloaddition Reaction , Microwaves , Molecular Structure , Pyrroles/chemistryABSTRACT
Readily accessible, low-valency glycoclusters based on a triazine core bearing D-galactose and L-fucose epitopes are able to inhibit biofilm formation by Pseudomonas aeruginosa. These multivalent ligands are simple to synthesize, are highly soluble, and can be either homofunctional or heterofunctional. The galactose-decorated cluster shows good affinity for Pseudomonas aeruginosa lectin lecA. They are convenient biological probes for investigating the roles of lecA and lecB in biofilm formation.
