Search results for "Chemical Synthesis"
showing 10 items of 285 documents
Synthesis of the phytohormone [11C]methyl jasmonate via methylation on a C18 Sep Pak? cartridge
2005
[11C]labeled (±)-methyl jasmonate was synthesized using a C18 Sep Pak™ at ∼100°C to sustain a solid-supported 11C-methylation reaction of sodium (±)-jasmonate using [11C]methyl iodide. After reaction, the Sep Pak was rinsed with acetone to elute the labeled product, and the solvent evaporated rendering [11C]-(±)-methyl jasmonate at 96% radiochemical purity. The substrate, (±)-jasmonic acid, was retained on the Sep Pak so further chromatography was unnecessary. Total synthesis time was 25 min from the end of bombardment (EOB) which included 15 min to generate [11C]methyl iodide using the GE Medical Systems PET Trace MeI system, 5 min for reaction and extraction from the cartridge, and 5 min …
Improved Regioselectivity in Pyrazole Formation through the Use of Fluorinated Alcohols as Solvents: Synthesis and Biological Activity of Fluorinated…
2008
The preparation of N-methylpyrazoles is usually accomplished through reaction of a suitable 1,3-diketone with methylhydrazine in ethanol as the solvent. This strategy, however, leads to the formation of regioisomeric mixtures of N-methylpyrazoles, which sometimes are difficult to separate. We have determined that the use of fluorinated alcohols such as 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as solvents dramatically increases the regioselectivity in the pyrazole formation, and we have used this modification in a straightforward synthesis of fluorinated analogs of Tebufenpyrad with acaricide activity. Fil: Fustero, Santos. Universidad de Valencia; España Fil…
On the reaction of some 5-polyfluoroaryl-1,2,4-oxadiazoles with methylhydrazine: synthesis of fluorinated indazoles
2009
The reaction of 5-polyfluoroaryl-1,2,4-oxadiazoles with methylhydrazine has been studied and the synthesis of fluorinated N-methylindazoles has been realized. Rearrangement reactions showed predominantly formation of N(1)-methylindazole regioisomers. Starting compounds were preliminarily functionalized at the polyfluoroaryl moiety through fluorine displacement with nucleophiles (methanol, methylamine, dimethylamine), allowing the obtainment of target indazoles substituted at the C(6) position.
3,5-bis(3'-indolyl)pyrazoles, analogues of marine alkaloid nortopsentin: synthesis and antitumor properties.
2007
A series of 10 bis-indolylpyrazoles of type 9, 10 were obtained by cyclization of diketones 8 using hydrazine monohydrate or methylhydrazine in refluxing acetic acid/THF. Derivatives 9a,c,d were selected, by the National Cancer Institute (NCI, Bethesda, USA), to be evaluated against the full panel of about 60 human tumor cell lines derived from nine human cancer cell types and showed antiproliferative activity in the micromolar range. In particular, 9d, the most active compound was effective against all the tested cell lines with a GI(50) mean value of 3.23 microM; TGI and LC(50) values were 14.5 and 58.9 microM having positive response on 91% and 41% of the tested cell lines, respectively.
Design, synthesis, and SAR analysis of cytotoxic sinapyl alcohol derivatives.
2005
Five series totalling 51 of sinapyl alcohol derivatives were designed and synthesized. Their cytotoxicity analyses were performed oil six human tumor cell lines Such as PC-3. CNE, KB, A549, BEL-7404, and HeLa. Certain sinapyl alcohol derivatives showed significant cytotoxic activities. Compound 14d exhibited especially potent cytotoxicity against the BEL-7404 cell line with an IC50 value of 0.7 mu M, which showed more cytotoxic activity than the positive control, cisplatin. The structure-cytotoxicity relationships were discussed and the CoMFA analysis was performed using the cytotoxic data against HeLa cells as a template. (c) 2005 Elsevier Ltd. All rights reserved.
Synthesis and Biological Evaluation of 1-Methyl-2-(3',4',5'-trimethoxybenzoyl)-3-aminoindoles as a New Class of Antimitotic Agents and Tubulin Inhibi…
2008
The 2-(3,4,5-trimethoxybenzoyl)-2-aminoindole nucleus was used as the fundamental structure for the synthesis of compounds modified with respect to positions C-4 to C-7 with different moieties (chloro, methyl, or methoxy). Additional structural variations concerned the indole nitrogen, which was alkylated with small alkyl groups such as methyl or ethyl. We have identified 1-methyl-2-(3,4,5-trimethoxybenzoyl)-3-amino-7-methoxyindole as a new highly potent antiproliferative agent that targets tubulin at the colchicine binding site and leads to apoptotic cell death.
Variations of acidic functions at position 2 and substituents at positions 4, 5 and 6 of the indole moiety and their effect on NMDA-glycine site affi…
2003
The synthetic procedures to obtain indole derivatives with different acidic functions at position 2 of the indole are reported. The synthesised and tested derivatives comprise 5-tetrazolyl, 1,3,4-oxadiazol-5-yl-2-one, and indole-2-carboxylic acid amides with 5-aminotetrazole, methanesulphonamide and trifluoromethanesulphonamide moieties. The binding affinity was evaluated using [3H]MDL 105,519 and pig cortical brain membranes. In general, compounds with acidic functions different from a carboxylic acid moiety are less potent than indole-2-carboxylic acid derivatives. Also, the 4,6-dichloro substitution pattern was compared to 5-tert-butyl derivatives and compounds not substituted in the ben…
New antitumoral acetogenin ‘Guanacone type’ derivatives: Isolation and bioactivity. Molecular dynamics simulation of diacetyl-guanacone
2007
We describe herein the isolation and semisynthesis of four acetogenin derivatives (1-4) as well as their ability to inhibit the mitochondrial respiratory chain and several tumor cell lines. In addition, four nanoseconds (ns) of MD simulation of compound 4, in a fully hydrated POPC bilayer, is reported.
Synthesis of enantiopure pyrrolidine-derived peptidomimetics and oligo-beta-peptides via nucleophilic ring-opening of beta-lactams.
2006
The synthesis of the two enantiomers of pyrrolidine-derived spiro beta-lactams by resolution with D- and L-Boc phenylalanine is described. The potential of these optically active spiro beta-lactams on the synthesis of peptidomimetics as analogues of melanostatin is evaluated. Theoretical studies of several models, at the Becke3LYP/6-31+G* level of theory, together with previous experimental evidences from our group, gathered by NMR, allow us to design structures that can efficiently mimic some biologically active peptide-type molecules. On the other hand, the spiro beta-lactams have shown their utility in the preparation of beta-peptides. As an example, a homo-tetra-beta-peptide was synthes…
Stereoselective synthesis of the published structure of feigrisolide A. Structural revision of feigrisolides A and B.
2006
The total synthesis of the proposed structure of feigrisolide A is reported. Ethyl (S)-3-hydroxybutyrate was the chiral starting material. A Brown asymmetric allylation and an Evans aldol reaction were key steps of the synthesis. The NMR data of the synthetic product are different from those of the natural product. The published structure of feigrisolide A is therefore erroneous. A subsequent comparison of spectral data strongly suggests that feigrisolides A and B are identical with (-)-nonactic acid and (+)-homononactic acid, respectively.