Oxime Derivatives Research Articles

Design, Synthesis and Bioactivities of Novel Isoxazole-Containing Pyrazole Oxime Derivatives.

In this study, in order to find novel biologically active pyrazole oxime derivatives, twenty-eight new pyrazole oxime compounds containing a substituted isoxazole ring were synthesized and evaluated for their acaricidaland insecticidal activities. Bioassays exhibited that some target compounds indicated good acaricidal and insecticidal activities against Tetranychus cinnabarinus, Aphis medicaginis, Mythimna separata, and Nilaparvata lugens. Especially, compounds 9c, 9h, 9u, and 9v showed 100.00%, 90.56%, 90.78%, and 90.62% insecticidal activities against A. medicaginis at the concentration of 20 μg/mL, respectively, compounds 9k and 9u had 70.86% and 100.00% insecticidal activities against M. separata at 20 μg/mL, respectively.

Preparation of New Oxadiazole Acyclic Nucleoside and Thioglycoside Analogs Containing Chromene Moiety with Antimicrobial Evaluation

New sugar hydrazones linked to chroman ring system and their derived oxadiazole acyclic nucleoside analogs were synthesized from the substituted ethyl ester oxime derivative. The 2-sustituted 1,3,4-oxadiazole-5-thione prepared from acid hydrazide was glycosylated to afford the corresponding thioglycosides, not the N-linked glycosides. The novel compounds were evaluated for their antimicrobial activity and showed different degrees of activities.

Synthesis and biological evaluation of sulfur-containing shikonin oxime derivatives as potential antineoplastic agents

As a continuation of our research on developing potent and potentially safe antineoplastic agents, a set of forty five sulfur-containing shikonin oxime derivatives were synthesized and evaluated for their in vitro cytotoxic activity against human colon cancer (HCT-15), gastric carcinoma (MGC-803), liver (Bel7402), breast (MCF-7) cancer cells and human skin fibroblast (HSF) cells. All the synthesized compounds exhibited potent cytotoxic activity selectively towards HCT-15 cells and did not display apparent toxicity to the normal HSF cells, some of which were more or comparatively effective to the parent compound against HCT-15, MGC-803 and Bel7402 cells. The most active agent 9m displayed high potency against human cancer cells with IC50 ranging from 0.27 ± 0.02 to 9.23 ± 0.12 μM. The structure-activity relationships (SARs) studies suggested that the nature of substituent group in the side chain is important for antitumor potency in vitro. Additionally, nitric oxide release studies revealed that the amount of nitric oxide generated from these oxime derivatives was relatively low. Furthermore, cellular mechanism investigations indicated that compound 9m could arrest cell cycle at G1 phase and induce a strong apoptotic response in HCT-15 cells. Moreover, western blot studies revealed that compound 9m induced apoptosis through the down-regulation of Bcl-2 and up-regulation of Bax, caspase 3 and 9. For all these reasons, compound 9m hold promising potential as antineoplastic agent.

Argentatin B derivatives induce cell cycle arrest and DNA damage in human colon cancer cells through p73/p53 regulation

The unique etiology of cancer requires a multidimensional approach for its treatment, control, and prevention. Therefore, all approaches to drug discovery and development should be exploited. Argentatin B (1) is a cycloartane triterpene isolated from Parthenium argentatum with inhibitory activity on tumor lines. The aim of this study is to investigate the inhibitory effect of 1 and 10 derivatives on the proliferation of a human colon cancer cell line (RKO), their genotoxic effects on human lymphocytes, as well as their potential effect on tumor protein (TP)-p53 and TP73 expression and phosphorylation. Argentatin B was found to induce reduced survival of RKO cells and showed a cytostatic effect. However, it did not induce apoptosis of RKO cells at the concentrations tested. Argentatin B and its derivatives were found to arrest the cell cycle at the G1 phase. The bromine 2 and oxime 6 derivatives were more active than 1. Furthermore, 1 and its bromine (2) and oxime (6) derivatives induced phosphorylation of (TP)-p53 and TP73. Nevertheless, 2 exhibited a greater genotoxic effect on normal human lymphocytes than 6.

Synthesis and biological activities of cyclanone O-(2-(3-aryl-4- amino-4H-1,2,4-triazol-3-yl)thio)acetyl)oxime derivatives

GRAPHICAL ABSTRACT

Investigation of O‐Sulfonylation‐promoted Heterolytic NO Bond Cleavage of Amidoximes and Ketoximes

Two different reaction pathways were observed in the sulfonylation of N‐phenylbenzamidoximes. The reaction with o‐NsCl at a heating temperature gave N,N′‐diphenylureas via Tiemann rearrangement, while the reaction with Ts2O at a lower temperature formed 2‐phenylbenzimidazoles via intramolecular electrophilic aromatic substitution. When the amide nitrogen was replaced with carbon substituents, oxime derivatives of benzoins and benzils underwent Beckmann fragmentation reactions upon sulfonylation, whereas sulfonylation of 2‐phenylacetophenone oxime afforded exclusively the Beckmann rearrangement adduct.

Iminyl‐Radicals by Oxidation of α‐Imino‐oxy Acids: Photoredox‐Neutral Alkene Carboimination for the Synthesis of Pyrrolines

AbstractThe visible‐light‐promoted decarboxylation of α‐imino‐oxy propionic acids for the generation of iminyl radicals has been accomplished through the use of Ir(dFCF3ppy)2(dtbbpy)PF6 as a photoredox catalyst. Different from visible‐light‐promoted homolysis and single‐electron reduction of oxime derivatives, this strategy provides a novel catalytic cycle for alkene carboimination through a sequence comprising N‐radical generation, iminyl radical cyclization, intermolecular conjugate addition to a Michael acceptor, and single‐electron reduction to afford various pyrroline derivatives in an overall redox‐neutral process. The indolizidine alkaloid skeleton could be easily constructed from a pyrroline derivative prepared by this synthetic method.

Iminyl‐Radicals by Oxidation of α‐Imino‐oxy Acids: Photoredox‐Neutral Alkene Carboimination for the Synthesis of Pyrrolines

The visible-light-promoted decarboxylation of α-imino-oxy propionic acids for the generation of iminyl radicals has been accomplished through the use of Ir(dFCF3 ppy)2 (dtbbpy)PF6 as a photoredox catalyst. Different from visible-light-promoted homolysis and single-electron reduction of oxime derivatives, this strategy provides a novel catalytic cycle for alkene carboimination through a sequence comprising N-radical generation, iminyl radical cyclization, intermolecular conjugate addition to a Michael acceptor, and single-electron reduction to afford various pyrroline derivatives in an overall redox-neutral process. The indolizidine alkaloid skeleton could be easily constructed from a pyrroline derivative prepared by this synthetic method.

Role of [dbnd]NOH intermolecular interactions in oxime derivatives via Crystal structure, Hirshfeld surface, PIXELC and DFT calculations

Oximes are building block of organic synthesis and they have wide range applications in laboratories, industries, and pharmaceutical as antidotes. Herein we report the crystal structures of oxime derivative Beta-p-Dimethylaminodeoxybenzionoxime (I) and o-Chloro-p-dimethylaminodeoxybenzion (II) the precursor molecule of o-Chloro-p-dimethylaminodeoxybenzionoxime and their intermolecular interactions studies through Hirshfeld surface & 2D-fingerprint plot analysis along with PIXELC and DFT calculations. The packing arrangements in I and II are driven by OH⋯N and OH⋯C interactions respectively. The OH⋯N hydrogen bonding in I facilitates the formation of the dimer with the motif of R (22(6)), whereas in II absence of oxime moiety (NOH) restricts the dimer formation. The 2D-fingerprint plot shows the close contacts for the intermolecular interactions in I & II. The PIXELC calculation of II suggests OH⋯C contributes for intermolecular interaction that stabilizes the crystal packing with the total energy value of 60.4 kcal/mol. The DFT calculation using B3LYP with 6-311G (d, p) functional set for both the derivatives shows a small deviation in the benzene ring (I) and chlorobenzene ring (II) with the RMSD value of 0.5095 Å and 0.8472 Å respectively.

New norfloxacin/nitric oxide donor hybrids: Synthesis and nitric oxide release measurement using a modified Griess colorimetric method

Oximes and nitrate esters are considered as important nitric oxide (NO) donors with diverse biological activities. Herein, we report the synthesis and characterization of new oxime and nitrate ester derivatives of norfloxacin as potential NO donor hybrids with expected synergistic antimicrobial activity. The release of NO from those hybrids was measured by a modified Griess method in which p- nitroaniline was employed instead of sulfanilamide. The increased electrophilicity of the intermediate 4 - nitroaniline diazonium salt accelerated the coupling process and shortened the overall assessment time. The improved detection limits and enhanced sensitivity would pave the way for the future application of this method in nitrite determination in biological or non-biological systems.

Synthesis and biological evaluation of novel steroidal 5α,8α-epidioxyandrost-6-ene-3β-ol-17-(O-phenylacetamide)oxime derivatives as potential anticancer agents

Inspired by the significant anti-cancer activity of our previously screened natural ergosterol peroxide (EP, 1), we synthesized and characterized a series of novel 5α,8α-epidioxyandrost-3β-ol-17-(O-phenylacetamide)oxime derivatives (9a–o). The anti-proliferative activity of the synthesized compounds against human hepatocellular carcinoma cells (HepG2, Sk-Hep1) and human breast cancer cells (MCF-7, MDA-MB231) were investigated. Compounds 9d, 9f, 9h, 9j and 9m displayed good anti-proliferative activity (most IC50<20μM) in vitro. Furthermore, fluorescence imaging showed that the designed coumarin-9d conjugate (12) localized mainly in mitochondria, leading to enhanced anticancer activities over the parent structure.

Proteomic analysis of food borne pathogens following the mode of action of the disinfectants based on pyridoxal oxime derivatives

A comprehensive proteomic analysis of food borne pathogens after treatment with disinfectants based on ammonium salts of pyridinium oxime was performed. Changes in proteomes of the Gram-positive bacterium Bacillus subtilis and the Gram-negative one, Escherichia coli, were evaluated. Up and down-regulated proteins in these bacteria after growth under the inhibition with four different disinfectants based on chloride and bromide salts of pyridinium oxime were identified and their cellular localizations and functions were determined by gene ontology searching. Proteome changes presented here demonstrate different mechanisms of action of these disinfectants. In the Gram-positive food pathogen Bacillus subtilis, the inhibitory substances seem to act mainly at the cell surface and cause significant alterations of membrane and cell surface proteins. On the other hand, intracellular proteins were more affected in the Gram-negative pathogen Escherichia coli. This research is a contribution to the investigation of the virulence and pathogenicity of food borne bacteria and their survival under stress conditions, and can also lead the way for further development of new inhibitors of microbial growth and studies of mechanism of their actions.

Synthesis and Study of Some New Quinolone Derivatives Containing a 3-acetyl Coumarin for Their Antibacterial and Antifungal Activities.

A series of N-[2-(8-metoxy-2H-chromen-2-one)ethyl] piperazinyl quinolones containing a carbonyl related functional groups (oxo or oxyimino) on the ethyl spacer of coumarin and piperazin rings was synthesized and studied for their antibacterial and antifungal activities . The synthesis of compounds (6a-6l) was achieved through the versatile and efficient synthetic route that involved reaction of quinolones with appropriately α- bromo ketone or α- bromo oxime derivatives (2, 2a-c). The structures of the new compounds were confirmed by IR, Mass, 1H-NMR and 13C-NMR spectra. More good activities against gram-positive and gram-negative are shown in all compounds. The antifungal data reveals that all compounds have shown weak antifungal activity as compared to Nistatin.

6-Substituted 1,4-naphthoquinone oxime derivatives (I): synthesis and evaluation of their cytotoxic activity

A series of 6-substituted 1,4-naphthoquinone oxime derivatives were synthesized and evaluated for their in vitro cytotoxicity against four cancer cell lines and one normal cell line. Some compounds exhibited moderate to good cytotoxicity towards cancer cells and meanwhile all the synthesized compounds displayed no apparent cytotoxic activity against normal cells (IC50 > 100 μM). Among these oxime derivatives, three compounds showed more potent cytotoxicity against human colon cancer cell lines (HCT-15) than adriamycin and 5-fluorouracil, with an IC50 value of 2.52, 1.96, and 2.27 μM, respectively. Additionally, structure–activity relationship studies revealed that cytotoxic effects of these oxime derivatives were not only largely dependent upon the size of alkyl chain R1, but also upon substituents R2 of the branch chain, indicating that the strong cytotoxicity of these compounds was ascribed to their appropriate lipophilicity. Collectively, this study could provide available strategy for design and synthesis of 6-substituted 1,4-naphthoquinone oxime derivatives as potential anticancer agents.

Oxime-modified aluminium(III) alkoxides: Potential precursors for γ-alumina nano-powders and optically transparent alumina film

Reactions of aluminium(III) iso-propoxide with acetoxime in anhydrous benzene yielded complexes of the type [Al(OiPr)3-n{ONC(CH3)2}n], where n=1, 2 or 3. These complexes were characterized by elemental analysis, FTIR and NMR (1H, 13C, 27Al) spectral studies. Spectral studies of these complexes suggest the presence of bi-dentate mode of the oximato moieties in the solution state. Soft transformations of aluminium(III) iso-propoxide and their oxime derivatives to pure alumina were carried out by the sol-gel technique. The powder XRD patterns of all the formed alumina suggest formation of cubic phase (γ-alumina) with average crystallites size of 7–30nm. Optically transparent crack free alumina film was deposited on glass substrate using alumina sol, prepared by complex [Al(OiPr){ONC(CH3)2}], through dip coating method. The film sintered at 500°C is amorphous in nature as indicated by XRD study. The alumina film is found to be ∼95% optically transparent in the visible region. The observed particle size distribution of alumina thin film in AFM images is found to be 13±2nm.

A catalytic approach to synthesis of PLP analogs and other environmental protocols in a single handed CaO/TiO2 green nanoparticle

As our precursory stage we have focus straight forward on clean catalytic approach for the production of C3 substituted pyridoxal-5′-phosphate analogues of vitamin B6, and other environmental protocols like photocatalytic activity, green fossil fuels and c–c coupling using efficient biocompatible eggshell related unrivalled materials which show versatility of the catalytic effect on different inorganic support. The eggshell immobilized nanoparticles have encouraging relevance in creation of new molecules and can advantageously be studied by various spectroscopic, thermal and elemental analyses like powder X-ray diffraction (XRD), Raman spectroscopy, UV–vis, Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area analysis. The elucidate nature of nanoparticles offer: more active site acts as lewis acid, vacancies on the catalyst surface and good to better yield of C3 substituted deoxy and 2-nor deoxy coenzyme pyridoxine (PN), coupling products propargylamines (PA), photo degrading enhancement of MB and nucleophilic substituted fatty acid (BD). This enzyme cofactor explore molecular synthons to synthetic equivalent: 3-deoxy and 2-nor-3-deoxy pyridoxal (PL), pyridoxal oxime (PO), pyridoxamine (PM) and mono phosphate derivative of 3-deoxyPM, 3-deoxyPL respectively and chemistry of selective oxidation and schiff base mechanism was studied and complemented through combined experimental and theoretical molecular orbital calculation consequently. The heterogeneous catalyst has strong selective ability towards selective reducing pyridine diester, bioactive intermediates substances and holds vast potential towards separation for the photogenerated electron-hole pairs and renewable, nontoxic, biodegradable green fossil fuels. The catalyst including environmental concern is reapplicable and strong impressive that can unfold the space of worthy metal component widely and facilitate the scope to take a vital role in different fileds like catalysis, biochemistry, nanoscience, energy and materials science.

Efficient synthesis and antimicrobial evaluation of 2-((1-substituted-1H-1,2,3-triazol-4-yl)-1-naphthaldehydes and their oxime derivatives

A series of 2-((1-substituted-1H-1,2,3-triazol-4-yl)-1-naphthaldehydes was prepared by the propargylation of 2-hydroxynaphthaldehyde followed by Copper(I)-catalyzed azide-alkyne cycloaddition with various organic azides. 2-((1-substituted-1H-1,2,3-triazol-4-yl)-1-naphthaldehyde analogues were transformed to corresponding oxime derivatives upon grinding with hydroxylamine hydrochloride under solvent free conditions. All the synthesized compounds were characterized by various analytical and spectral techniques and screened in vitro for antimicrobial activity. The activity data revealed that most of the compounds exhibited good to significant activities. Compounds 4c and 5c exhibited very good and broad spectrum activity towards all the tested bacterial strains. Further, to understand the binding interactions, 4c and 5c were docked into the active sites of E. coli topoisomerase II DNA gyrase.

Synthesis and antiviral activities of novel penta-1,4-diene-3-one oxime derivatives bearing a pyridine moiety

A series of novel penta-1,4-diene-3-one oxime ether derivatives bearing a pyridine moiety were designed and synthesized, and their antiviral activities against tobacco mosaic virus (TMV) were evaluated. The results of the biological assay indicated that most of the title compounds exhibit good antiviral activities against TMV at 500 μg/mL. In particular, the title compounds 5c, 5j, 5o and 5p showed remarkable curative activities against TMV, with EC50 values of 274.8, 299.2, 251.8 and 287.7 μg/mL, respectively, which were superior to that of ribavirin (379.8 μg/mL). This study indicates that penta-1,4-diene-3-one oxime ether derivatives bearing a pyridine moiety can serve as potential alternative templates in the search for novel, highly efficient, anti-plant viral agents.

Divergent Iron-Catalyzed Coupling of O-Acyloximes with Silyl Enol Ethers.

An iron-catalyzed coupling reaction of O-acyloximes and O-benzoyl amidoximes with silyl enol ethers is reported. The protocol provides access to functionalized pyrroles, 1,6-ketonitriles, pyrrolines and imidazolines via carbon-centered radicals generated from an initially formed iminyl radical. The intramolecular cyclization and ring-opening processes of the iminyl radical take place preferentially over reactions that proceed through a 1,3-hydrogen transfer, providing insights into iron-catalyzed reactions with oxime derivatives. The cheap and environmentally friendly iron catalyst, the broad substrate scope and the functional group compatibility make this protocol useful for synthesis of valuable nitrogen-containing products.

Synthesis and Extraction Studies of Calix[4]-Crown-4 Oxime Derivatives

The article comprises synthesis of calyx[4]-oxa-crown, and calix[4]-thia-crown compounds containing nitrile groups (3a, 3b) and amino groups (4a, 4b) and their corresponding oxime derivatives (5a, 5b) and liquid-liquid extraction studies of these compounds. The oxime derivatives of compounds (5a, 5b) have been synthesized by reacting of di-n-butylamino derivatives of calix[4]-oxa-crown, and calix[4]-thia-crown compounds (4a, 4b) with amphi-chloroglyoxime in methanol-THF. Their cation and anion transfer studies were performed by using liquid-liquid extraction procedure. It has been concluded from the observations that the compound 3a shows a good extraction behavior toward Na+ ion in the presence of other metal cations. Whereas, its oxime derivatives transfers all of the metal cations used in the liquid-liquid extraction studies.