99-77-4Relevant academic research and scientific papers
Further characterization of mitsunobu-type intermediates in the reaction of dialkyl azodicarboxylates with P(III) compounds
Kumara Swamy,Praveen Kumar,Bhuvan Kumar
, p. 1002 - 1008 (2006)
Structural characterization of compounds analogous to the proposed intermediates in the Mitsunobu esterification process is achieved by the combined use of NMR spectroscopy and X-ray diffractometric studies. The results show that compounds (t-BuNH)P(μ-N-t-Bu)2P[(N-t-Bu)(N-(CO 2R)-N(H)(CO2R))] [R = Et (11), i-Pr (12)], obtained by treating [(t-Bu-NH)P-μ-N-t-Bu]2 (10) with diethylazodicarboxylate (DEAD) or diisopropylazodicarboxylate (DIAD), respectively, have a structure with the NH proton residing between the two nitrogen atoms ((P)N(t-Bu) and (P)N-N(CO2Et)); this is the tautomeric form of the expected betaine (t-BuNH)P(μ-N-t-Bu)2P+[(NH-t-Bu)(N-(CO 2R)-N-(CO2R)]. Treatment of ClP(μ-N-t-Bu) 2P[(N-t-Bu){N-(CO2-i-Pr)-N(H)(CO2-i-Pr)] (6) with 2,6-dicholorophenol affords (2,6-Cl2-C6H 3-O)P-(μ-N-t-Bu)2P+[(NH-t-Bu){N[(CO 2i-Pr)(HNCO2i-Pr)]}](Cl-)(2,6-Cl 2-C6H3-OH) (14) that has a structure similar to that of (CF3CH2O)P(μ-N-t-Bu)2P +[(NH-t-Bu){N[(CO2i-Pr)(HNCO2i-Pr)]}](Cl -) (13), but with an additional hydrogen bonded phenol. Both of these have the protonated betaine structure analogous to that of Ph3P +N(CO2R)NH(CO2R)(R′CO2) - (2) proposed in the Mitsunobu esterification. Two other compounds, (ArO)P(μ-N-t-Bu)2P+(NH-t-Bu){N(CO2i-Pr) (HNCO2i-Pr)}(Cl-) [Ar = 2,6-Me2C 6H3O- (15) and 2-Me-6-t-Bu-C6H3-O- (16)], are also prepared by the same route. Although NMR tube reactions of 11 or 12 with tetrachlorocatechol, catechol, 2,2′-biphenol, and phenol revealed significant changes in the 31P NMR spectra, attempted isolation of these products was not successful. On the basis of 31P NMR spectra, the phosphonium salt structure (t-BuNH)P(μ-N-t-Bu)2P +[(HN-t-Bu){N-(CO2R)-N(H)(CO2R)]-(ArO -) is proposed for these. The weakly acidic propan-2-ol or water did not react with 11 or 12, Treatment of 12 with carboxylic acids/p-toluenesulfonic acid gave the products (t-BuNH)P(μ-N-t-Bu)2P+[(HN-t- Bu){N-(CO2-i-Pr)-N(H)(CO2-i-Pr)](ArCO2-) [Ar = Ph (18), 4-Cl-C6H4CH2 (19), 4-Br-C 6H4 (20), 4-NO2-C6H4 (21)] and (t-BuNH)P(μ-N-t-Bu)2P+|(HN-t-Bu){N-(CO 2-i-Pr)-N(H)(CO2-i-Pr)](4-CH3-C 6H4SO3-) (22) that have essentially the same structure as 2. Compound 18 has additional stabilization by hydrogen bonding, as revealed by X-ray structure determination. Finally it is shown that the in situ generated (t-BuNH)P(μ-N-t-Bu)2P+[(HN-t-Bu) {N-(CO2Et)-N(H)(CO2Et)](4-NO2-C 6H4CO2-) can also effect Mitsunobu esterification. A comparison of the Ph3P-DIAD system with the analogous synthetically useful Ph3P-dimethyl acetylenedicarboxylate (DMAD) system is made.
Synthesis, spectral analysis, antibacterial, antifungal, antioxidant and hemolytic activity studies of some new 2,5-disubstituted-1,3,4-oxadiazoles
Adole, Vishnu A.,Chobe, Santosh S.,Dhonnar, Sunil L.,Jagdale, Bapu S.,More, Rahul A.,Sadgir, Nutan V.
, (2022/01/04)
Series of 1,3,4-oxadiazole derivatives (5a–5g and 5h, 5i) were synthesized and characterized by FT-IR, 1H NMR, 13C NMR and HR-MS spectral analysis. All the target compounds were screened for their in vitro antibacterial activity against two Gram-negative bacterial strains namely Escherichia coli (MTCC 405) and Salmonella typhi (MTCC 3224) and two Gram-positive bacterial strains namely Bacillus subtilis (MTCC 1790) and Bacillus megaterium (MTCC 1684) and antifungal activity against Aspergillus niger (MTCC 282), Rhizopus oryzae (MTCC 262), Penicillium chrysogenum (MTCC 974), and Candida albicans (MTCC 183) fungal strains. The synthesized compounds exhibited significant antibacterial and antifungal potential. Three compounds (5e, 5f and 5g) have shown higher antibacterial activity with very low MIC values comparable to streptomycin. According to the SAR study, the antibacterial efficacy can be intensified by substituting fluoro and methyl substituents at the para position in acid hydrazide. The synthesized compounds were also screened for % radical scavenging activity by OH and DPPH assay and found to be good antioxidant agents. Besides, the hemolytic study revealed that the synthesized 1,3,4-oxadiazoles possessed negligible cytotoxicity compared with the standard.
The polyhedral nature of selenium-catalysed reactions: Se(iv) species instead of Se(vi) species make the difference in the on water selenium-mediated oxidation of arylamines
Capperucci, Antonella,Dalia, Camilla,Tanini, Damiano
supporting information, p. 5680 - 5686 (2021/08/16)
Selenium-catalysed oxidations are highly sought after in organic synthesis and biology. Herein, we report our studies on the on water selenium mediated oxidation of anilines. In the presence of diphenyl diselenide or benzeneseleninic acid, anilines react with hydrogen peroxide, providing direct and selective access to nitroarenes. On the other hand, the use of selenium dioxide or sodium selenite leads to azoxyarenes. Careful mechanistic analysis and 77Se NMR studies revealed that only Se(iv) species, such as benzeneperoxyseleninic acid, are the active oxidants involved in the catalytic cycle operating in water and leading to nitroarenes. While other selenium-catalysed oxidations occurring in organic solvents have been recently demonstrated to proceed through Se(vi) key intermediates, the on water oxidation of anilines to nitroarenes does not. These findings shed new light on the multifaceted nature of organoselenium-catalysed transformations and open new directions to exploit selenium-based catalysis.
Selective Mild Oxidation of Anilines into Nitroarenes by Catalytic Activation of Mesoporous Frameworks Linked with Gold-Loaded Mn3O4 Nanoparticles
Armatas, Gerasimos S.,Daikopoulou, Vassiliki,Koutsouroubi, Eirini D.,Lykakis, Ioannis N.,Skliri, Euaggelia
, (2021/11/01)
This work reports the synthesis and catalytic application of mesoporous Au-loaded Mn3O4 nanoparticle assemblies (MNAs) with different Au contents, i. e., 0.2, 0.5 and 1 wt %, towards the selective oxidation of anilines into the corresponding nitroarenes. Among common oxidants, as well as several supported gold nanoparticle platforms, Au/Mn3O4 MNAs containing 0.5 wt % Au with an average particle size of 3–4 nm show the best catalytic performance in the presence of tert-butyl hydroperoxide (TBHP) as a mild oxidant. In all cases, the corresponding nitroarenes were isolated in high to excellent yields (85–97 %) and selectivity (>98 %) from acetonitrile or greener solvents, such as ethyl acetate, after simple flash chromatography purification. The 0.5 % Au/Mn3O4 catalyst can be isolated and reused four times without a significant loss of its activity and can be applied successfully to a lab-scale reaction of p-toluidine (1 mmol) leading to the p-nitrotulene in 83 % yield. The presence of AuNPs on the Mn3O4 surface enhances the catalytic activity for the formation of the desired nitroarene. A reasonable mechanism was proposed including the plausible formation of two intermediates, the corresponding N-aryl hydroxylamine and the nitrosoarene.
Using m icrowave and ultrasound to synthesis of substituted bis-acyl hydrazone derivatives
Mohammed, Salim J.,Sheat, Attallah M.,A.abood, Salih,Yahya, Omar M.
, p. 6423 - 6427 (2021/11/01)
In this paper, some new bis-acyl hydrazone derivatives (4a-f) were prepared through the reaction of carboxylic acid hydrazides with 1,4-diacetylbenzene using classical methods, microwave and ultrasound irradiation methods. These compounds are obtained through a series of reactions where some carboxylic acids react with ethanol first in the presence of concentrated sulfuric acid to give the corresponding esters (2a-f), which when treatment with aqueous hydrazine give carboxylic acid hydrazides (3a-f).thus, The results proved that the use of microwave and ultrasound techniques is much better than the classical methods, as it gave a higher yield, shorter reaction time, and the absence of the use of solvents. All newly synthesized compounds were confirmed by IR, (1H & 13C) NMR spectral analysis and the corresponding reactions were monitored by TLC using the reported eluent.
Synthesis, characterization, and biological evaluation of new derivatives targeting MbtI as antitubercular agents
Mori, Matteo,Stelitano, Giovanni,Chiarelli, Laurent R.,Cazzaniga, Giulia,Gelain, Arianna,Barlocco, Daniela,Pini, Elena,Meneghetti, Fiorella,Villa, Stefania
, p. 1 - 17 (2021/02/26)
Tuberculosis (TB) causes millions of deaths every year, ranking as one of the most dangerous infectious diseases worldwide. Because several pathogenic strains of Mycobacterium tuberculosis (Mtb) have developed resistance against most of the established anti-TB drugs, new therapeutic options are urgently needed. An attractive target for the development of new antitubercular agents is the salicylate synthase MbtI, an essential enzyme for the mycobacterial siderophore biochemical machinery, absent in human cells. A set of analogues of I and II, two of the most potent MbtI inhibitors identified to date, was synthesized, characterized, and tested to elucidate the structural requirements for achieving an efficient MbtI inhibition and a potent antitubercular activity with this class of compounds. The structure-activity relationships (SAR) here discussed evidenced the importance of the furan as part of the pharmacophore and led to the preparation of six new compounds (IV-IX), which gave us the opportunity to examine a hitherto unexplored position of the phenyl ring. Among them emerged 5-(3-cyano-5-(trifluoromethyl)phenyl)furan-2-carboxylic acid (IV), endowed with comparable inhibitory properties to the previous leads, but a better antitubercular activity, which is a key issue in MbtI inhibitor research. Therefore, compound IV offers promising prospects for future studies on the development of novel agents against mycobacterial infections.
Development of Novel (+)-Nootkatone Thioethers Containing 1,3,4-Oxadiazole/Thiadiazole Moieties as Insecticide Candidates against Three Species of Insect Pests
Cheng, Wanqing,Fan, Jiangping,Guo, Yong,Han, Meiyue,Ma, Nannan,Yan, Xiaoting,Yang, Ruige
, p. 15544 - 15553 (2022/01/03)
To improve the insecticidal activity of (+)-nootkatone, a series of 42 (+)-nootkatone thioethers containing 1,3,4-oxadiazole/thiadiazole moieties were prepared to evaluate their insecticidal activities against Mythimna separata Walker, Myzus persicae Sulzer, and Plutella xylostella Linnaeus. Insecticidal evaluation revealed that most of the title derivatives exhibited more potent insecticidal activities than the precursor (+)-nootkatone after the introduction of 1,3,4-oxadiazole/thiadiazole on (+)-nootkatone. Among all of the (+)-nootkatone derivatives, compound 8c (1 mg/mL) exhibited the best growth inhibitory (GI) activity against M. separata with a final corrected mortality rate (CMR) of 71.4%, which was 1.54- and 1.43-fold that of (+)-nootkatone and toosendanin, respectively; 8c also displayed the most potent aphicidal activity against M. persicae with an LD50 value of 0.030 μg/larvae, which was closer to that of the commercial insecticidal etoxazole (0.026 μg/larvae); and 8s showed the best larvicidal activity against P. xylostella with an LC50 value of 0.27 mg/mL, which was 3.37-fold that of toosendanin and slightly higher than that of etoxazole (0.28 mg/mL). Furthermore, the control efficacy of 8s against P. xylostella in the pot experiments under greenhouse conditions was better than that of etoxazole. Structure-activity relationships (SARs) revealed that in most cases, the introduction of 1,3,4-oxadiazole/thiadiazole containing halophenyl groups at the C-13 position of (+)-nootkatone could obtain more active derivatives against M. separata, M. persicae, and P. xylostella than those containing other groups. In addition, toxicity assays indicated that these (+)-nootkatone derivatives had good selectivity to insects over nontarget organisms (normal mammalian NRK-52E cells and C. idella and N. denticulata fries) with relatively low toxicity. Therefore, the above results indicate that these (+)-nootkatone derivatives could be further explored as new lead compounds for the development of potential eco-friendly pesticides.
Sulfonated covalent triazine polymer loaded with Pd nanoparticles as a bifunctional catalyst for one pot hydrogenation esterification reaction
Ravi, S.,Raza, A. Ahmed,Sheriff, A. K. Ibrahim,Tajudeen, S. Syed
, (2021/07/17)
Highly dispersed Pd nanoparticles over covalent triazine polymer functionalized with sulfonic acid groups (CTP-SO3H/Pd) were prepared by facile Friedel-Crafts reaction, post synthetic sulfonation and Pd immobilization method. The prepared catalyst was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption, inductively coupled plasma - optical emission spectrometry (ICP-OES), elemental analysis and X-ray photoelectron spectroscopy (XPS). The sulfonic acid groups were grafted into the terphenyl backbone and the presence of triazine functionality within the framework enabled the uniform dispersion of palladium nanoparticles over the polymer network. When used as a bifunctional catalyst in one pot hydrogenation-esterification (OHE) reaction, the CTP-SO3H/Pd exhibited good activity and stability. The performance of CTP-SO3H/Pd is due to the surface-active acid/metal sites and was evident from the yield of the product in the reaction. The catalyst was easily recovered by filtration and recycle tests showed that it could be re-used for at least five repetitive runs with minor loss of catalytic activity suggesting its potential utility in OHE reaction. A plausible mechanistic pathway for OHE reaction over CTP-SO3H/Pd was also proposed.
New quinoxaline-2(1H)-ones as potential VEGFR-2 inhibitors: design, synthesis, molecular docking, ADMET profile and anti-proliferative evaluations
Abulkhair, Hamada S.,Eissa, Ibrahim H.,El-Adl, Khaled,ElSohly, Mahmoud A.,Elhendawy, Mostafa A.,Mehany, Ahmed. B. M.,Metwaly, Ahmed M.,Radwan, Mohamed M.,Sakr, Helmy M.,Yousef, Reda G.
, p. 16949 - 16964 (2021/09/27)
Eleven new quinoxaline derivatives were designed and synthesized as modified VEGFR-2 inhibitors of our previous work. The synthesized compounds were tested against three human cancer cell lines (HepG-2, MCF-7 and HCT-116). Compounds11g,11eand11cwere the most potent members against the tested cells. Compound11g(IC50= 4.50, 2.40, and 5.90 μM) was the most potent member compared to doxorubicin (IC50= 8.29, 9.65, and 7.68 μM) and sorafenib (IC50= 7.33, 9.41, and 7.23 μM) against HepG-2 and HCT-116, and MCF-7 cell lines, respectively. Compound11eshowed better anti-proliferative activities than doxorubicin and sorafenib with IC50values of 5.34, 4.19, and 6.06 μM, against HepG-2 and HCT-116 and MCF-7 cell lines, respectively. In addition, the most active anti-proliferative derivatives11c,11e,11f, and11gwere selected to evaluate their inhibitory activities against VEGFR-2. The tested compounds displayed good inhibitory activity with IC50values ranging from 0.75 to 1.36 μM. Among them, compound11gwas the most active member with an IC50value of 0.75 μM, compared to the reference drug; sorafenib (IC50= 1.29 μM). Moreover, docking studies revealed that the synthesized compounds have good binding patterns against the prospective molecular target; VEGFR-2. In addition,in silico, ADMET and toxicity studies showed a high level of drug likeness for the synthesized compounds.
Design, Synthesis, and Study of the Insecticidal Activity of Novel Steroidal 1,3,4-Oxadiazoles
Bai, Hangyu,Jiang, Weiqi,Li, Qi,Li, Tian,Ma, Shichuang,Shi, Baojun,Wu, Wenjun
, p. 11572 - 11581 (2021/10/12)
A series of novel steroidal derivatives with a substituted 1,3,4-oxadiazole structure was designed and synthesized, and the target compounds were evaluated for their insecticidal activity against five aphid species. Most of the tested compounds exhibited potent insecticidal activity against Eriosoma lanigerum (Hausmann), Myzus persicae, and Aphis citricola. Compounds 20g and 24g displayed the highest activity against E. lanigerum, showing LC50 values of 27.6 and 30.4 μg/mL, respectively. Ultrastructural changes in the midgut cells of E. lanigerum were detected by transmission electron microscopy, indicating that these steroidal oxazole derivatives might exert their insecticidal activity by destroying the mitochondria and nuclear membranes in insect midgut cells. Furthermore, a field trial showed that compound 20g exhibited effects similar to those of the positive controls chlorpyrifos and thiamethoxam against E. lanigerum, reaching a control rate of 89.5% at a dose of 200 μg/mL after 21 days. We also investigated the hydrolysis and metabolism of the target compounds in E. lanigerum by assaying the activities of three insecticide-detoxifying enzymes. Compound 20g at 50 μg/mL exhibited inhibitory action on carboxylesterase similar to the known inhibitor triphenyl phosphate. The above results demonstrate the potential of these steroidal oxazole derivatives to be developed as novel pesticides.
