3235-04-9Relevant academic research and scientific papers
Dioxido-vanadium(V) complex catalyzed oxidation of alcohols and tandem synthesis of oximes: a simple catalytic protocol for C–N bond formation
Kurbah, Sunshine Dominic
, p. 905 - 918 (2021/02/03)
We report the synthesis of a vanadium(V) complex characterized by FT-IR and 1H NMR spectroscopy. The structure of the complex was established by single crystal X-ray crystallography. We also carried out the catalytic oxidation of benzyl alcohol, hetero-aryl alcohols and propargylic alcohols. Tandem synthesis of oximes from alcohols were also carried out using our vanadium(V) complex. The newly synthesized complex acts as a catalyst for oxidation reactions and tandem synthesis of oxime from alcohols.
On the mixed oxides-supported niobium catalyst towards benzylamine oxidation
Granato, álisson Silva,de Carvalho, Gustavo S. Gon?alves,Fonseca, Carla G.,Adrio, Javier,Leit?o, Alexandre A.,Amarante, Giovanni Wilson
, p. 118 - 125 (2020/09/11)
A series of mixed oxides-supported niobium-based catalysts has been synthesized and applied towards oxidation reactions of benzylamine derivatives. Under the optimized reaction conditions, the selectivity to oxime enhanced, leading to the main product with up to 72 %. Moreover, even α-substituted benzylamines were well tolerated and led to oximes in good isolated yields. It is important to mention; four equivalents of the harmless and inexpensive hydrogen peroxide were employed as oxidizing agent. Mechanism hypothesis suggested that the reaction proceed to selective benzylamine oxidation into nitroso intermediate, following by formation of the corresponding oxime tautomer mediated by an unstable water produced by NbOx supported catalyst. This consists the first mixed oxides-supported niobium-based catalyst for selective oxidation of benzylamines to oximes.
Poly(N-vinylimidazole): A biocompatible and biodegradable functional polymer, metal-free, and highly recyclable heterogeneous catalyst for the mechanochemical synthesis of oximes
Fahim, Hoda,Ghaffari Khaligh, Nader,Gorjian, Hayedeh
, p. 2007 - 2012 (2022/01/08)
The catalytic activity of poly(N-vinylimidazole), a biocompatible and biodegradable synthetic functional polymer, was investigated for the synthesis of oximes as an efficient, halogen-free, and reusable heterogeneous catalyst. The corresponding oximes were afforded in high to excellent yields at room temperature and in short times using the planetary ball mill technique. Some merits, such as the short reaction times and good yields for poorly active carbonyl compounds, and avoiding toxic, expensive, metal-containing catalysts, and hazardous and flammable solvents, can be mentioned for the current catalytic synthesis of the oximes. Furthermore, the heterogeneous organocatalyst could be easily separated after the reaction, and the regenerated catalyst was reused several times with no significant loss of its catalytic activity.
Design, synthesis and biological evaluation of novel indanone containing spiroisoxazoline derivatives with selective COX-2 inhibition as anticancer agents
Abolhasani, Hoda,Zarghi, Afshin,Komeili Movahhed, Tahereh,Abolhasani, Ahmad,Daraei, Bahram,Dastmalchi, Siavoush
, (2021/01/25)
Objective: A new family of 3′-(Mono, di or tri-substituted phenyl)-4′-(4-(methylsulfonyl) phenyl) spiroisoxazoline derivatives containing indanone spirobridge was designed, synthesized, and evaluated for their selective COX-2 inhibitory potency and cytotoxicity on different cell lines. Methods: A synthetic reaction based on 1,3-dipolar cycloaddition mechanism was applied for the regiospecific formation of various spiroisoxazolines. The activity of the newly synthesized compounds was determined using in vitro cyclooxygenase inhibition assay. The toxicity of the compounds was evaluated by MTT assay. In addition, induction of apoptosis, and expression levels of Bax, Bcl-2 and caspase-3 mRNA in MCF-7 cells were evaluated following exposure to compound 9f. The docking calculations and molecular dynamics simulation were performed to study the most probable modes of interactions of compound 9f upon binding to COX-2 enzyme. Results: The docking results showed that the synthesized compounds were able to form hydrogen bonds with COX-2 involving methyl sulfonyl, spiroisoxazoline, meta-methoxy and fluoro functional groups. Spiroisoxazoline derivatives containing methoxy group at the C-3′ phenyl ring meta position (9f and 9g) showed superior selectivity with higher potency of inhibiting COX-2 enzyme. Furthermore, compound 9f, which possesses 3,4-dimethoxyphenyl on C-3′ carbon atom of isoxazoline ring, exhibited the highest COX-2 inhibitory activity, and also displayed the most potent cytotoxicity on MCF-7 cells with an IC50 value of 0.03 ± 0.01 μM, comparable with that of doxorubicin (IC50 of 0.062 ± 0.012 μM). The results indicated that compound 9f could promote apoptosis. Also, compared to the control group, the mRNA expression of Bax and caspase-3 significantly increased, while that of Bcl-2 significantly decreased upon exposure to compound 9f which may propose the activation of mitochondrial-associated pathway as the mechanism of observed apoptosis. Conclusion: In vitro biological evaluations accompanied with in silico studies revealed that indanone tricyclic spiroisoxazoline derivatives are good candidates for the development of new anti-inflammatory and anticancer (colorectal and breast) agents.
Visible-Light-Mediated Strategies for the Preparation of Oxime Ethers Derived from O-H Insertions of Oximes into Aryldiazoacetates
Duarte, Marcelo,Jurberg, Igor D.,Le?o, Luiz Paulo M. O.,Saito, Felipe A.,Stivanin, Mateus L.
supporting information, p. 17528 - 17532 (2021/12/02)
Two visible-light-mediated O-H insertion protocols involving oximes and aryldiazoacetates leading to different products depending on the solvent employed are reported. In DCM, direct O-H insertion takes place. In THF, there is the additional incorporation of the ring-opened form of this solvent into the structure of the product. These metal-free protocols are mild and tolerant to air and moisture. The preparation of an acaricide has been developed as an example of synthetic application.
1,3-dipolar cycloaddition reactions of the compound obtaining from cyclopentadiene-PTAD and biological activities of adducts formed selectively
Bayrak, Cetin,Menzek, Abdullah,Taskin-Tok, Tugba,Taslimi, Parham,Yavari, Mirali Akbar
, (2022/01/04)
After known adduct (4) was synthesized by cycloaddition reaction of cyclopentadiene with 4-phenyl-1,2,4-triazoline-3,5-dione, seven new isoxazoline derivatives were synthesized from reactions of 4 with corresponding oximes prepared from benzaldehyde derivatives in the existence of the aqueous NaOCl in CH2Cl2 at 0°C—RT via nitrile oxides. Four new pyrazoline derivatives were also synthesized from reactions of 4 with corresponding prepared reagents via nitrile imines. Selectively, each of all isoxazole and pyrazoline derivatives was synthesized by 1,3-dipolar cycloaddition reactions of compound 4 with the corresponding reagents. Based on the results of their biological activity analyses, Ki values for acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and alpha-glucosidase (α-Gly) enzymes were obtained in this range 32.15 ± 5.73–107.44 ± 19.52 22.57 ± 4.30–186.07 ± 23.51, and 69.08 ± 8.54–528.07 ± 38.46 nM, respectively. Besides that, these compounds were subjected to molecular docking to describe the interaction against AChE, BChE, and α-Gly enzymes in which important interactions were visualized and evaluated with residues of the binding region in each target enzyme.
Enolate-Based Regioselective Anti-Beckmann C-C Bond Cleavage of Ketones
Jahn, Ullrich,Ma?ek, Tomá?
, p. 11608 - 11632 (2021/09/02)
The Baeyer-Villiger or Beckmann rearrangements are established methods for the cleavage of ketone derivatives under acidic conditions, proceeding for unsymmetrical precursors selectively at the more substituted site. However, the fragmentation regioselectivity cannot be switched and fragmentation at the less-substituted terminus is so far not possible. We report here that the reaction of ketone enolates with commercial alkyl nitrites provides a direct and regioselective way of fragmenting ketones into esters and oximes or ω-hydroxyimino esters, respectively. A comprehensive study of the scope of this reaction with respect to ketone classes and alkyl nitrites is presented. Control over the site of cleavage is gained through regioselective enolate formation by various bases. Oxidation of kinetic enolates of unsymmetrical ketones leads to the otherwise unavailable "anti-Beckmann"cleavage at the less-substituted side chain, while cleavage of thermodynamic enolates of the same ketones represents an alternative to the Baeyer-Villiger oxidation or the Beckmann rearrangement under basic conditions. The method is suited for the transformation of natural products and enables access to orthogonally reactive dicarbonyl compounds.
1,3-Dipolar Cycloaddition, HPLC Enantioseparation, and Docking Studies of Saccharin/Isoxazole and Saccharin/Isoxazoline Derivatives as Selective Carbonic Anhydrase IX and XII Inhibitors
D'Ascenzio, Melissa,Secci, Daniela,Carradori, Simone,Zara, Susi,Guglielmi, Paolo,Cirilli, Roberto,Pierini, Marco,Poli, Giulio,Tuccinardi, Tiziano,Angeli, Andrea,Supuran, Claudiu T.
, p. 2470 - 2488 (2020/03/31)
Two series of saccharin/isoxazole and saccharin/isoxazoline hybrids were synthesized by 1,3-dipolar cycloaddition. The new compounds showed to be endowed with potent and selective inhibitory activity against the cancer-related human carbonic anhydrase (hCA) IX and XII isoforms in the nanomolar range, while no affinity was encountered for off-targets, such as hCA I and II. Successive enantioseparation on a milligram scale of the most representative compounds led to the discovery that (S)-isomers were more potent than their corresponding (R)-enantiomers. Lastly, molecular modeling studies were conducted to define those structural requirements that were responsible for the discrimination among selected human isoforms of carbonic anhydrases. Two nanomolar hCA IX and XII inhibitors were also screened for their selective toxicity against non tumoral primary cells (fibroblasts) and against a breast adenocarcinoma cell line (MCF7) in hypoxic environment. The efficacious combination of these compounds with doxorubicin on MCF7 cells was demonstrated after 72 h of treatment.
Potassium Poly(Heptazine Imide): Transition Metal-Free Solid-State Triplet Sensitizer in Cascade Energy Transfer and [3+2]-cycloadditions
Antonietti, Markus,Guldi, Dirk M.,Hussain, Tanveer,Karton, Amir,Markushyna, Yevheniia,Mazzanti, Stefano,Oschatz, Martin,Sánchez Vadillo, José Manuel,Savateev, Aleksandr,Strauss, Volker,Tarakina, Nadezda V.,Tyutyunnik, Alexander P.,Walczak, Ralf,ten Brummelhuis, Katharina
supporting information, p. 15061 - 15068 (2020/06/17)
Polymeric carbon nitride materials have been used in numerous light-to-energy conversion applications ranging from photocatalysis to optoelectronics. For a new application and modelling, we first refined the crystal structure of potassium poly(heptazine imide) (K-PHI)—a benchmark carbon nitride material in photocatalysis—by means of X-ray powder diffraction and transmission electron microscopy. Using the crystal structure of K-PHI, periodic DFT calculations were performed to calculate the density-of-states (DOS) and localize intra band states (IBS). IBS were found to be responsible for the enhanced K-PHI absorption in the near IR region, to serve as electron traps, and to be useful in energy transfer reactions. Once excited with visible light, carbon nitrides, in addition to the direct recombination, can also undergo singlet–triplet intersystem crossing. We utilized the K-PHI centered triplet excited states to trigger a cascade of energy transfer reactions and, in turn, to sensitize, for example, singlet oxygen (1O2) as a starting point to synthesis up to 25 different N-rich heterocycles.
Microwave synthesis method of benzaldoxime compounds
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Paragraph 0044-0047, (2020/12/08)
The invention discloses a microwave synthesis method of benzaldoxime compounds. The method comprises the following steps: dissolving a substituted benzaldehyde, hydroxylamine hydrochloride and an alkaline compound in an organic solvent, placing the formed solution in a microwave reaction kettle for a reaction, spin-drying the solvent after the reaction is finished, conducting mixed extraction withethyl acetate and water, separating an organic phase, carrying out drying with anhydrous sodium sulfate, and successively performing filtering and desolventizing to obtain a benzaldoxime compound. Based on the structure of the substituted benzaldehyde, the substituted benzaldoxime compound is obtained by reacting the aldehyde with hydroxylamine hydrochloride in the microwave reaction kettle. Themethod is simple in process, convenient to operate, short in reaction time and high in yield, meets the requirement for environment friendliness and improves economic benefits.
