Search results for "Chemical Synthesis"
showing 10 items of 285 documents
Herbicidal derivatives of aminomethylenebisphosphonic acid. Part III. Structure-activity relationship.
1997
Derivatives of aminomethylenebisphosphonic acids constitute a class of promising herbicides. More than 40 N-substituted aminomethylenephosphonic acids were synthesized and evaluated for their herbicidal activity on common cress (Lepidium sativum L.) and cucumber (Cucumis sativus L.). Some of the tested compounds were found to exhibit strong herbicidal properties being equal in activity with the popular herbicide glyphosate as well as parent N-pyridylaminomethylenephosphonic acids. N-Substituted iminodi(methylenephosphonic) acids, which may be considered as close analog of glyphosate, were inactive toward test plants.
Direct Metal‐ and Reagent‐Free Sulfonylation of Phenols with Sodium Sulfinates by Electrosynthesis
2019
A novel electrochemical strategy for the synthesis of aryl sulfones by direct sulfonylation of phenols with sodium sulfinates has been developed. The C,S-coupling products are of particular interest for chemical synthesis, material sciences and pharmaceutical sciences. By using this metal- and reagent-free electrochemical method, aryl and diaryl sulfones can be obtained directly in good yields. The established one-step protocol is easy to perform, scalable, inherently safe, and enables a broad scope, which is not limited by quinoid-forming substrates.
Cyclic dipeptides: catalyst/promoter-free, rapid and environmentally benign cyclization of free amino acids
2011
“The best catalyst is no catalyst.” With growing public concern over global warming and the amount of greenhouse gases, it is important to reduce the amount of chemicals and eliminate waste, to obtain better results in a simple, selective, safe, and environmentally benign fashion compared to conventional tedious chemical synthesis. Herein, we disclose an environmentally benign, rapid, catalyst/promoter/coupling reagent-free cyclization procedure of free amino acids to furnish exclusively cyclic dipeptides (2,5-diketopiperazines, DKPs) in excellent or even quantitative yield, along with their solid state self-assembling properties. This process is extremely simple and highly efficient with l…
Syntheses of (+)-alismoxide and (+)-4-epi-alismoxide.
2006
The first total syntheses of (+)-alismoxide and (+)-4-epi-alismoxide are reported. Formal chemo-, regio-, and stereoselective addition of water to 10alpha-acetoxy-1alphaH,5betaH-guaia-3,6-diene afforded the target compounds after reduction. The absolute stereochemistry of (+)-alismoxide has been established. The low [alpha](D) +8.6 value indicates that significant amounts of alismoxide result from biosynthetic processes. Furthermore, the structure of the natural guaienediol isolated from Silphium perfoliatum has been corrected to (-)-alismoxide.
Synthesis and induction of G0–G1 phase arrest with apoptosis of 3,5-dimethyl-6-phenyl-8-(trifluoromethyl)-5,6-dihydropyrazolo[3,4-f][1,2,3,5]tetrazep…
2007
The multistep synthesis of 3,5-dimethyl-6-phenyl-8-(trifluoromethyl)-5,6-dihydropyrazolo[3,4-f][1,2,3,5]tetrazepin-4(3H)-one 15 has been carried out. The compound showed antiproliferative and apoptotic effects against K562, K562-R (imatinib mesilate resistant), HL60 and multidrug resistant (MDR) HL60 cell lines. Compound 15 showed a pro-apoptotic activity against HL60 and K562 resistant cell lines markedly higher than etoposide and busulfan, respectively. Flow cytometry studies carried out on K562 cells allowed to establish that 15 induces G0-G1 phase arrest followed by apoptosis.
Concise and modular synthesis of regioisomeric haptens for the production of high-affinity and stereoselective antibodies to the strobilurin azoxystr…
2011
The immune response to regioisomeric haptens of azoxystrobin with varied derivatization sites was studied. Based on the Sonogashira and Suzuki-Miyaura couplings and following a straightforward modular design, we have synthesized four haptens with the same linker anchored through C-C bonds and located at different sites of the molecule. The most stereoselective antibodies were produced from immunogens with the spacer arm at a distal position from the β-methoxyacrylate moiety characteristic of strobilurins. Moreover, we observed that assay cross-reactivity was reliant on the functionalization site of the competitor derivative. Finally, the antibody binding site was explored using synthetic ch…
Hapten synthesis, monoclonal antibody generation, and development of competitive immunoassays for the analysis of picoxystrobin in beer.
2010
Abstract This paper describes the original synthesis of a functionalized derivative of the fungicide picoxystrobin and the generation of the first reported monoclonal antibodies against this strobilurin pesticide. The synthetic hapten was prepared by total synthesis from commercial chemicals and incorporating the spacer arm through a carbon–carbon single bond. Also, to obtain the immunogen, an uncommon hapten activation strategy based on N,N′-disuccinimidyl carbonate was employed, affording high activation yields and clean and reproducible coupling results. With these immunoreagents, two enzyme-linked immunosorbent assays (ELISAs) were developed: a competitive one-step assay using the antib…
Layered double hydroxide (LDH)–organic hybrids as precursors for low-temperature chemical synthesis of carbon nanoforms
2012
A low-temperature route for the chemical synthesis of diverse carbon nanoforms, including nano-onions and multi-walled nanotubes, is described. The method involves thermal decomposition of a sebacate-intercalated NiFe LDH at 400 °C and benefits from the catalytic activity of FeNi3 nanoparticles generated in situ.
Synthesis and Antiproliferative Activity of Novel 3-(Indazol-3-yl)-quinazolin-4(3H)-one and 3-(Indazol-3-yl)-benzotriazin-4(3H)-one Derivatives
1999
Several new 3-(indazol-3-yl)-quinazolin-4(3H)-one and 3-(indazol-3-yl)-benzotriazin-4(3H)-one derivatives 5 and 6 were synthesized and tested for their in vitro antiproliferative activity against Raji, K562, and K562-R cell lines. The pharmacological screening showed that some 2, 6, or 7-substituted quinazolinones 5 posses a significant antiproliferative activity, with a percentage growth inhibition ranging from 44.8% to 100% at 50 microM, which was higher than that showed by the unsubstituted derivative 5a previously synthesized. For the most active compounds 5d, 5f, and 5g the IC50 were recorded.
Synthesis and antiproliferative activity of triazenoindazoles and triazenopyrazoles: a comparative study.
2003
Several triazenoindazoles and triazenopyrazoles were prepared transforming the appropriate aminoindazoles and aminopyrazoles in the corresponding diazonium salts which were reacted with dimethylamine, diethylamine and pyrrolidine. All the triazenes were tested for their antiproliferative activity against K562, HL60, L1210 and MCF7 cell lines. The biological data showed that the benzocondensation plays a positive role on the antiproliferative activity. The (1)H-NMR spectra showed that the rotational barrier around the N(2)-N(3) bond in the triazene group can be influenced both by the position of this group in the indazole nucleus and by the substitution pattern in the benzene moiety.