621-98-7Relevant academic research and scientific papers
Synthesis of lithium/cesium-Zagronas from zagrosian natural asphalt and study of their activity as novel, green, heterogeneous and homogeneous nanocatalysts in the Claisen–Schmidt and Knoevenagel condensations
Soleiman-Beigi, Mohammad,Ghalavand, Saba,Venovel, Hadis Gholami,Kohzadi, Homa
, p. 3267 - 3279 (2021/06/17)
A novel, heterogeneous and homogeneous basic nanocatalysts were synthesized by grafting of lithium and cesium on zagrosian natural asphalt sulfonate (Li/Cs-Zagronas). The activity of these catalysts was examined in the Claisen–Schmidt and Knoevenagel condensations under mild reaction conditions. Li/Cs-Zagronas were characterized by FT-IR spectroscopy, scanning electron microscopy, X-ray diffraction, energy-dispersive spectroscopy, inductively coupled plasma and thermogravimetric analysis techniques. These nanocatalysts were removed by simple filtration and reused several times without any deterioration of activity.
Potassium Natural Asphalt Sulfonate (K-NAS): Synthesis and characterization as a new recyclable solid basic nanocatalyst and its application in the formation of carbon–carbon bonds
Falah, Saeid,Soleiman-Beigi, Mohammad,Kohzadi, Homa
, (2020/07/06)
In this research, we synthesized and characterized a new heterogeneous basic nanocatalyst and its catalytic application was studied in the Claisen-Schmidt and Knoevenagel condensations. In order to prepare this nanocatalyst, first, the Iranian natural asphalt was sulfonated with the concentrated sulfuric acid and then, converted to the potassium natural asphalt sulfonate (K-NAS). In order to characterization of the nanocatalyst, used of FT-IR spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), inductively coupled plasma (ICP) and thermogravimetric analysis (TGA) techniques. This new basic heterogeneous nanocatalyst have advantages such as being eco-friendly, huge specific surface area, high reactivity and recyclability.
Electrospray ionization tandem mass spectrometry of monoketone curcuminoids
Vieira, Tatiana M.,Orenha, Renato P.,Crevelin, Eduardo J.,Furtado, Saulo S.P.,Vessecchi, Ricardo,Parreira, Renato L.T.,Crotti, Ant?nio E.M.
, (2020/02/18)
Rationale: Although monoketone curcuminoids (MKCs) have been largely investigated due to their biological activities, data on the gas-phase fragmentation reactions of protonated MKCs under collision-induced dissociation (CID) conditions are still scarce. Here, we combined electrospray ionization tandem mass spectrometry (ESI-MS/MS) data, multiple-stage mass spectrometry (MSn), deuterium exchange experiments, accurate-mass data, and thermochemical data estimated by computational chemistry to elucidate and to rationalize the fragmentation pathways of eleven synthetic MKCs. Methods: The MKCs were synthesized by Claisen-Schmidt condensation under basic (1–9) or acidic (10–11) conditions. ESI-CID-MS/MS analyses and deuterium-exchange experiments were carried out on a triple quadrupole mass spectrometer. MSn analyses on an ion trap mass spectrometer helped to elucidate the fragmentation pathways. Accurate-mass data and thermochemical data, obtained at the B3LYP/6–31+G(d,p) level of theory, were used to support the ion structures. Results: The most intense product ions were the benzyl ions ([C7H2R1R2R3R4R5]+) and the acylium ions ([M + H ? C8H3R1R2R3R4R5]+), which originated directly from the precursor ion as a result of two competitive hydrogen rearrangements. Product ions [M + H – H2O]+ and [M + H ? C6HR1R2R3R4R5]+, which are formed after Nazarov cyclization, were also common to all the analyzed compounds. In addition, ?Br and ?Cl eliminations were diagnostic for the presence of these halogen atoms at the aromatic ring, whereas ?CH3 eliminations were useful to identify the methyl and methoxy groups attached to this same ring. Nazarov cyclization in the gas phase occurred for all the investigated MKCs and did not depend on the presence of the hydroxyl group at the aromatic ring. However, the presence and the position of a hydroxyl group at the aromatic rings played a key role in the Nazarov cyclization mechanism. Conclusions: Our results reinforce some aspects of the fragmentation pathways previously published for 1,5-bis-(2-methoxyphenyl)-1,4-pentadien-3-one and 1,5-bis-(2-hydroxyphenyl)-1,4-pentadien-3-one. The alternative fragmentation mechanism proposed herein can explain the fragmentation of a wider diversity of monoketone curcuminoids.
Naphtho[2,3-: B] furan-4,9-dione synthesis via palladium-catalyzed reverse hydrogenolysis
Li, Jimei,Zhang, Jie,Li, Mingfei,Zhang, Chenyang,Yuan, Yongkun,Liu, Renhua
supporting information, p. 2348 - 2351 (2019/02/27)
A reverse hydrogenolysis process has been developed for two-site coupling of 2-hydroxy-1,4-naphthoquinones with olefins to produce naphtha[2,3-b]furan-4,9-diones and hydrogen (H2). The reaction is catalyzed by commercially available Pd/C without oxidants and hydrogen acceptors, thereby providing an intrinsically waste-free approach for the synthesis of functionalized and potentially biologically relevant naphtha[2,3-b]furan-4,9-diones.
Antimicrobial Activity of Monoketone Curcuminoids Against Cariogenic Bacteria
Vieira, Tatiana M.,dos Santos, Isabella A.,Silva, Thayná S.,Martins, Carlos H. G.,Crotti, Ant?nio E. M.
, (2018/08/01)
We evaluated the antimicrobial activity of 25 monoketone curcuminoids (MKCs) against a representative panel of cariogenic bacteria in terms of their minimum inhibitory concentration (MIC) values. Curcumin A (10) displayed promising activity against Streptococcus mutans (MIC?=?50?μg/ml) and Streptococcus mitis (MIC?=?50?μg/ml) as well as moderate activity against S.?sanguinis (MIC?=?100?μg/ml), Lactobacillus casei (MIC?=?100?μg/ml), and Streptococcus salivarius (MIC?=?200?μg/ml). Results indicated higher activity of compound 10 than that of its bis-β-diketone analog. Additionally, compounds 3a (1,5-bis(4-methylphenyl)pentan-3-one) and 7b (1,5-bis(4-bromophenyl)pentan-3-ol) were moderately active against S.?mitis (MIC?=?100?μg/ml) and S.?salivarus (MIC?=?200?μg/ml).
Reaction of CH-acids with Michael acceptors in the presence of potassium carbonate. Syntheses of 6-acetyl- and 3,5-dialkylcyclohex-2-enones
Khachatryan,Vardapetyan,Morlyan,Razinov,Matevosyan
, p. 385 - 390 (2015/10/29)
The reaction of acetylacetone with α,β-enones in the presence of potassium carbonate affords 6-acetylcyclohex-2-enones. The assembly of two acetoacetate and one alkanal molecules gives 3,5-dialkylcyclohex-2-enones. Facile one-pot procedures for these reactions were developed.
Spectral characterization and crystal structure of some 2,6-diarylthian-4-one hydrazone derivatives
Sankar,Umamatheswari,Pandiarajan
, p. 554 - 563 (2015/01/08)
A series of cis and trans 2,6-diarylthian-4-one hydrazone derivatives (11-16) have been synthesized and characterized by 1H, 13C and two dimensional NMR spectroscopy. For the 2r,6t-diphenylthian-4-one N-isonicotinoylhydrazone (14) X-ray diffraction have also been recorded. The coupling constants suggested that the cis-hydrazones (11-13), which have the phenyl groups in cis orientation, largely exist in chair conformations with equatorial orientation of the phenyl groups 11C. Analysis of the vicinal coupling constants of trans-hydrazones (14-16) suggests that boat forms 14B must make significant contributions to it and the relative population is 58%. Moreover, in solution chair conformations 14C and 14C′, may contribute to 14. The NOESY and X-ray diffraction of 14 gives definite evidence for the contribution of 14C.
I2-mediated oxidative C-N bond formation for metal-free one-pot synthesis of di-, tri-, and tetrasubstituted pyrazoles from α,β-unsaturated aldehydes/ketones and hydrazines
Zhang, Xinting,Kang, Jinfeng,Niu, Pengfei,Wu, Jie,Yu, Wenquan,Chang, Junbiao
, p. 10170 - 10178 (2015/02/19)
An I2-mediated metal-free oxidative C-N bond formation methodology has been established for the regioselective pyrazole synthesis. This practical and eco-friendly one-pot protocol requires no isolation of the less stable intermediates hydrazone
Synthesis of 2-(1,5-diaryl-1,4-pentadien-3-ylidene)- hydrazinecarboximidamide hydrochloride catalyzed by p-dodecylbenzenesulfonic acid in aqueous media under ultrasound irradiation
Li, Ji-Tai,Du, Chao,Xu, Xiao-Ya,Chen, Guo-Fen
experimental part, p. 1033 - 1038 (2012/07/03)
Amidinohydrazone compounds are very important synthetic intermediates and can serve as versatile precursors in synthesis of many natural products and drug molecules. The use of ultrasound, p-dodecylbenzenesulfonic acid (DBSA) and water as solvent improved the synthesis of different 2-(1,5-diaryl-1,4- pentadien-3-ylidene)-hydrazinecarboximidamide hydrochlorides. The best reaction conditions for the condensation of 1,5-diphenyl-1,4-pentadien-3-one with aminoguanidine hydrochloride were as follows: 1,5-diphenyl-1,4-pentadiene-3-one (1, 1 mmol), aminoguanidine hydrochloride (1.1 mmol), DBSA (0.5 mmol), water 10 mL, reaction temperature 25-27°C, irradiation frequency 25 kHz. 2a was achieved in 94% yield within 2 h. The other seven amidinohydrazones were obtained in 84-94% yield within 2-3 h under the same conditions. Compared to the method involving catalysis by hydrochloric acid in refluxing EtOH, the advantages of present procedure are milder conditions, shorter reaction times, higher yields, and environmental friendly conditions, which make it a useful strategy for the synthesis of analogues.
Synthesis, spectral, crystal and antimicrobial studies of biologically potent oxime ethers of nitrogen, oxygen and sulfur heterocycles
Parthiban, Paramasivam,Aridoss, Gopalakrishnan,Rathika, Paramasivam,Ramkumar, Venkatachalam,Kabilan, Senthamaraikannan
scheme or table, p. 2981 - 2985 (2010/03/03)
Three series of oxime ethers viz, 2,6-diarylpiperidin-4-one O-benzyloximes 5a-o, 2,6-diaryltetrahydropyran-4-one O-benzyloximes 7a-e and 2,6-diaryltetrahydrothiopyran-4-one O-benzyloximes 11a-b and 12a-c were synthesized and stereochemistry is established by their spectral and single crystal analysis. A SAR study has been carried out for the above oxime ethers against a panel of antibacterial (Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Escherichia coli) and antifungal agents (Candida albicans, Candida-51, Rhizopus sp., Aspergillus niger, Aspergillus flavus and Cryptococcus neoformans), respectively, using Ciprofloxacin and Amphotericin B as standards. Most of the chloro/methyl/methoxy substituted compounds exerted moderate to good activity against all the tested organisms; moreover, some compounds (5i, 5l, 5n, 5o, 7c2, 7d1, 7d2, 7e, 11b and 12c) exhibited promising activity than standard drugs.
