Search results for "DISCOVERY"
showing 10 items of 4119 documents
Synthesis of substituted carbamo(dithioperoxo)thioates as potential BCA2-inhibitory anticancer agents
2015
A new, simple, one-step synthetic route to carbamo(dithioperoxo)thioates from commercially available starting materials is described. The key step of this new synthetic approach involves the tetrabromomethane-promoted reaction between secondary amines, carbon disulfide and alkyl thiols under basic conditions at room temperature. New compounds from this series selected for anticancer screening showed selective sub-micromolar activity within BCA2-expressing human breast cancer cell lines.
Solid–liquid extraction of ω-amino acids using ditopic receptors
2008
Abstract Five heteroditopic ligands have been prepared to be used in solid–liquid extraction of ω-amino acids into DMSO solutions. The prepared ligands contain crown ethers as cation binding sites and thiourea or amide groups for anion recognition. The aliphatic zone of the 1H NMR spectra suggests that two different species related to the amino acid are present in solution. One of these species is the complexed zwitterionic form and the other seems to be free non-zwitterionic amino acid. The presence of these two species allows extraction efficiencies higher than 100%.
Synthesis and biological evaluation of antimalarial and antileukemic activity of new C-10 modified artemisinin derivatives
2021
Abstract Several non-acetal artemisinin derivatives were synthesized and their antimalarial activity against chloroquine-resistant parasites as well as their antileukemic activity were investigated. The azide 10 was proved to have slightly better activity than the current antimalarial drugs such as artesunate and chloroquine. In addition, the azide 10 and the aldehyde 7 were found to be effective in decreasing cell proliferation in leukemia cells.
Direct observation and thermal transformations of dications derived from dibenzotropylium ions
1992
Abstract Carboxylic acid 1 and its derivatives 2 , 3 treated with triflic acid below −20°C afford the dications 1H 2+2- 3H 2+2. Cyclodehydration above 20°C (or in the gas-phase, CIMS of 3 ) leads to the diprotonated ketone 4H 2+2.
Synthesis of elemane bis-lactones structurally related to vernolepin
1998
Abstract The chemical transformation of santonin into an elemane bis -lactone structurally related to the antitumour compound vernolepin is reported. The transformation of ring A of santonin into a hemiacetal δ-lactone was achieved in eleven steps. The spectroscopic characteristics of the synthetic product obtained in this way revealed that the proposed structure for the natural product should be revised.
Electrochemical carboxylation of benzal chloride
1984
Abstract The clectrocarboxylation of benzal chloride to -chlorophenylacetic and phenylmalonic acids is realized in diaphragmless cells with aluminium sacrificial anodes. Yields respectively up to 50% and 30% can be obtained. Phenylacetic acid is always present among the products.
A new and expeditious strategy for the synthesis of β-amino acids from Δ2-oxazolines
2001
Abstract A new, mild two-step synthesis of racemic β-amino acids starting from 2-alkyl-Δ2-oxazolines is described. The process implies the initial formation of masked N-substituted or N-unsubstituted β-enamino acid derivatives followed by chemoselective reduction of the enamino moiety. The process takes place with high yields, total chemoselectivity and moderate diastereoselectivity.
Alkali metal complexation properties of resorcinarene bis-crown ethers: effect of the crown ether functionality and preorganization on complexation
2008
Abstract The synthesis and characterization of tetramethoxy resorcinarene tribenzo-bis-crown ethers, m - and p -TBBC6 , are described. The effect of the added aromatic functionality in the crown ether bridge on the alkali metal complexation properties was investigated and compared to the properties of tetramethoxy resorcinarene bis-crown-5 ( BC5 ) by means of 1 H NMR spectroscopy and X-ray crystallography. It was found that BC5 and m -TBBC6 were capable of binding alkali metal cations (K + , Rb + , and Cs + ), with the highest affinity toward Cs + cation, while no binding was observed in the case of p -TBBC6 , which confirms the significance of the complementarity and preorganization for co…
A two-step synthesis of new macrobicyclic aza-ligands starting from “trans”dioxocyclam as diprotected macrocycle
1997
Abstract A rapid and convenient synthesis of two small aza-cryptands containing a 1,4,8,11-tetraazacyclotetradecane backbone is reported. This strategy can be applied to the preparation of many other aza-cages by varying the nature of the cross linker. Moreover, the two remaining secondary amine sites may allow the functionalization of these ligands or their grafting on a polymer.
Syntheses of novelN-([18F]fluoroalkyl)-N-nitroso-4-methyl-benzenesulfonamides and decomposition studies of corresponding19F- and bromo-analogues: pot…
2003
N-([ 18 F]fluoroalkyl)-N-nitroso-4-methyl-benzensulfonamides [n-alkyl = (-CH 2 ) [ 18,19 F]F, n=2-4)] were synthesized in radiochemical yields ranging from 75-90% to provide new secondary labelling precursors for the syntheses of 18 F-labelled compounds. Preliminary decomposition studies utilizing the corresponding non-radioactive 19 F-compounds as well as the bromo containing analogous compounds were performed to evaluate their stability regarding temperature and basicity of the labelling medium. Furthermore, initial difficulties in labelling these compounds led to the development of a modified labelling procedure applying nearly solvent-free conditions. Extensive decomposition experiments…