5729-06-6Relevant academic research and scientific papers
Influence of Symmetry on the Luminescence and Radiative Lifetime of Nine-Coordinate Europium Complexes
Shavaleev, Nail M.,Eliseeva, Svetlana V.,Scopelliti, Rosario,Bünzli, Jean-Claude G.
, p. 9166 - 9173 (2015)
Homoleptic mononuclear nine-coordinate lanthanum(III) and europium(III) tris-complexes [Ln(N^N^O)3]·nH2O with two tridentate N-benzylbenzimidazole pyridine-2-carboxylates exhibit a rare C3-symmetry of the lanthanide coordi
Hydroboration and reductive amination of ketones and aldehydes with HBpin by a bench stable Pd(ii)-catalyst
Biswas, Bhaskar,Devadkar, Ajitrao Kisan,Gupta, Puneet,Joshi, Mayank,Mahato, Shreya,Panda, Tarun K.,Rawal, Parveen,Roy Choudhury, Angshuman
supporting information, p. 1103 - 1111 (2022/02/11)
A palladium(ii) complex [(κ4-{1,2-C6H4(NCH-C6H4O)2}Pd] (1) supported by a dianionic salen ligand [1,2-C6H4(NCH-C6H4O)2]2- (L) was synthesised and used as a molecular pre-catalyst in the hydroboration of aldehydes and ketones. The molecular structure of Pd(ii) complex 1 was established by single-crystal X-ray diffraction analysis. Complex 1 was tested as a competent pre-catalyst in the hydroboration of aldehydes and ketones with pinacolborane (HBpin) to produce corresponding boronate esters in excellent yields at ambient temperature under solvent-free conditions. Further, the complex 1 proved to be a competent catalyst in the reductive amination of aldehydes with HBpin and primary amines under mild and solvent-free conditions to afford a high yield (up to 97%) of corresponding secondary amines. Both protocols provided high conversion, superior selectivity and broad substrate scope, from electron-withdrawing to electron-donating and heterocyclic substitutions. A computational study based on density functional theory (DFT) revealed a reaction mechanism for Pd-catalysed hydroboration of carbonyl species in the presence of HBpin. The protocols also uncovered the dual role of HBpin in achieving the hydroboration reaction.
Nucleophilic aromatic substitution reactions under aqueous, mild conditions using polymeric additive HPMC
Ansari, Tharique N.,Borlinghaus, Niginia,Braje, Leon H.,Braje, Wilfried M.,Handa, Sachin,Ogulu, Deborah,Wittmann, Valentin
supporting information, p. 3955 - 3962 (2021/06/17)
The use of the inexpensive, benign, and sustainable polymer, hydroxypropyl methylcellulose (HPMC), in water enables nucleophilic aromatic subsitution (SNAr) reactions between various nucleophiles and electrophiles. The mild reaction conditions facilitate a broad functional group tolerance that can be utilized for subsequent derivatization for the synthesis of pharmaceutically relevant building blocks. The use of only equimolar amounts of all reagents and water as reaction solvent reveals the greenness and sustainability of the methodology presented herein.
Cp*Co(iii) and Cu(OAc)2bimetallic catalysis for Buchwald-type C-N cross coupling of aryl chlorides and amines under base, inert gas & solvent-free conditions
Srivastava, Avinash K.,Sharma, Charu,Joshi, Raj K.
supporting information, p. 8248 - 8253 (2020/12/29)
A strategy involving bimetallic catalysis with a combination of Cp?Co(CO)I2 and Cu(OAc)2 was used for performing Buchwald-type C-N coupling reactions of aryl chlorides with amines. The reactions proceeded at 100 °C to produce excellent yields of many of the desired C-N coupled products, in 4 h, under aerobic reaction conditions. The reactions were shown to run under base-free and solvent-free conditions, enabling this strategy to work efficiently for electron-withdrawing and base-sensitive functionalities. The presented methodology was found to be equally efficient for electron-donating functionalities as well as for primary (1°) and secondary (2°) aromatic and aliphatic amines. Moreover, the products were easily separated through the extractions of the organic aqueous layer, with this process chromatographic separations is not required.
Half-sandwich (η5-Cp?)Rh(iii) complexes of pyrazolated organo-sulfur/selenium/tellurium ligands: Efficient catalysts for base/solvent free C-N coupling of chloroarenes under aerobic conditions
Joshi, Raj Kumar,Sharma, Charu,Sharma, Kamal Nayan,Srivastava, Avinash Kumar
supporting information, p. 3599 - 3606 (2020/06/10)
Three new pyrazolated chalcogenoether ligated Rh(iii) half-sandwich complexes (1-3) were synthesised by the thermal reaction of chalcogenoether (S, Se and Te) substituted 1H-pyrazole ligands (L1-L3) and [(η5-C5Me5)RhCl]2 in methanol. The complexes were fully characterised by various spectroscopic techniques, and the molecular structures of complexes 1 and2 were also established through single crystal X-ray crystallographic analysis, which indicates a pseudo-octahedral half-sandwich piano-stool geometry around the rhodium metal. All three complexes were found to be thermally stable and insensitive towards air and moisture. One mol% of Rh(iii) complexes (1-3) along with 10 mol% of Cu(OAc)2 were explored for the Buchwald-Hartwig type C-N coupling reactions of amine and aryl chloride. Good to excellent yields (89-92%) of the coupling products were obtained with seleno- and thio-ether functionalised pyrazolated Rh(iii) complexes (1 and 2), while an average yield (39%) was obtained with the telluro-ether functionalised complex (3). In contrast to the previously reported C-N coupling reactions the present reaction works under solvent- and base-free conditions, and the coupling reaction is accomplished in just 6 h with a high yield of the coupling product. The present methodology was also found to be efficient for a wide variety of functionalised aryl halides, and aliphatic or aromatic amines (1° and 2°). Moreover, the reaction also enables the C-N coupling of electron-withdrawing substrates and base-sensitive functionalities.
Ru(II) complexes containing (2-(pyren-1-ylmethylene)hydrazinyl)benzothiazole: Synthesis, solid-state structure, computational study and catalysis in N-alkylation reactions
Murugan, Kaliyappan,Ojwach, Stephen O.,Saravanan, Kandasamy,Vijayan, Paranthaman,Vijayapritha, Subbarayan,Viswanathamurthi, Periasamy
, (2020/07/27)
Reactions of (2-(pyren-1-ylmethylene)hydrazinyl)benzothiazole (L) with ruthenium(II) prefabricated precursors [RuHCl(CO)(EPh3)3] and [RuH2(CO)(EPh3)3] (E = P or As) afforded new Ru(II) complexes [RuCl(CO)(EPh3)2(L)] and [RuH(CO)(EPh3)2(L)] (E = P or As) (1–4). All the Ru(II) complexes (1–4) were characterized by IR, NMR spectroscopies, ESI-mass spectrometry and elemental analyses. The solid-state structures of Ru(II) complexes (2 and 3) were established by single crystal X-ray analyses and revealed distorted octahedral geometries around the ruthenium(II) ion and mono anionic bidentate N^N coordination mode for hydrazine ligand. The Ru(II) complexes 2 and 3 were also analyzed using Hirshfeld surface analysis and DFT calculations. Moreover, all the complexes (1–4) were utilized in the N-alkylation reactions of amines using alcohol. Complex 3 was found to be highly active towards N-alkylation of different aromatic amines with alcohol.
Heterostructured Hybrid rGO@α-MnO2/rGO@δ-MnO2 Nanoflower: An Efficient Catalyst for Aerobic Solvent-Free N-Alkylation Reactions and Energy Storage Material
Chaudhuri, Haribandhu,Karak, Niranjan
, p. 1617 - 1629 (2020/02/18)
A new reduced graphene oxide (rGO) based bi-phasic crystal of MnO2, namely α-MnO2 nanorods and δ-MnO2 nanoflakes containing heterostructured hybrid nanoflower rGO@α-MnO2/rGO@δ-MnO2 has been fabricated through a facile hydrothermal method followed by annealing treatment. The successful synthesis of the hybrid material was studied by XRD, Raman, BET, FESEM with EDX, FTIR and TEM analyses. An efficient N-alkylation reaction of substituted aromatic amines with aromatic alcohols was carried out under solvent-free aerobic conditions in the presence of catalytic amount of rGO@α-MnO2/rGO@δ-MnO2. The catalyst shows excellent activity in terms of high yields (up to 98 %), short reaction time (10 h) along with a simple work-up process. The spent material can be regenerated several times without causing any serious decrease in catalytic activity. Moreover, cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and cyclic stability techniques were executed to evaluate the performances of rGO@α-MnO2, rGO@δ-MnO2, and rGO@α-MnO2/rGO@δ-MnO2 as energy storage materials. Among all those materials, rGO@α-MnO2/rGO@δ-MnO2 exhibited a proficient specific capacitance, CS (267 F/g at 1 A/g) along with excellent cycling ability (～83 % retention up to 10000 cycles). The superb electrochemical performance of rGO@α-MnO2/rGO@δ-MnO2 might be ascribed to the combination of bi-phasic α-MnO2 and δ-MnO2 with rGO sheets, resulting in a flower-like structure.
Benzimidazole Derivatives as Novel Zika Virus Inhibitors
Anh, Le Duc,De, Tran Quang,Duc Thanh, Danh La,Dupont-Rouzeyrol, Myrielle,Grailhe, Regis,Hue, Bui Thi Buu,Jo, Eunji,Nguyen, Phuong Hong,Son, Nguyen Hoang,Thoa, Than Thi,Van Hieu, Mai,Van Tuan, Nguyen,Windisch, Marc P.
supporting information, p. 1453 - 1463 (2020/05/25)
We have synthesized 50 benzimidazole (BMZ) derivatives with 1,2-phenylenediamines and aromatic aldehydes under mild oxidation conditions by using inexpensive, nontoxic inorganic salt sodium metabisulfite in a one-pot condensation reaction and screened their ability to interfere with Zika virus (ZIKV) infection utilizing a cell-based phenotypic assay. Seven BMZs inhibited an African ZIKV strain with a selectivity index (SI=CC50/EC50) of 9–37. Structure-activity relationship analysis demonstrated that substitution at the C-2, N-1, and C-5 positions of the BMZ ring were important for anti-ZIKV activity. The hybrid structure of BMZ and naphthalene rings was a structural feature responsible for the high anti-ZIKV activity. Importantly, BMZs inhibited ZIKV in human neural stem cells, a physiologically relevant system considering the severe congenital anomalies, like microcephaly, caused by ZIKV infection. Compound 39 displayed the highest antiviral efficacy against the African ZIKV strain in Huh-7 (SI>37) and neural stem cells (SI=12). Compound 35 possessed the highest activity in Vero cells (SI=115). Together, our data indicate that BMZs derivatives have to be considered for the development of ZIKV therapeutic interventions.
Unsymmetrically-Substituted 5,12-dihydrodibenzo[b,f][1,4]diazocine-6,11-dione Scaffold—A Useful Tool for Bioactive Molecules Design
Bieszczad, Bartosz,Dudek, Marta K.,Garbicz, Damian,Grzesiuk, El?bieta,Mieczkowski, Adam,Trzybiński, Damian,Wo?niak, Krzysztof
, (2020/07/02)
Unsymmetrically N-substituted and N,N’-disubstituted 5,12-dihydrodibenzo [b,f][1,4]diazocine-6,11-diones were synthesized in the new protocol. The desired modifications of the dibenzodiazocine scaffold were introduced at the stages of proper selection of building blocks as well as post-cyclization modifications with alkylation or acylation agents, expanding the structural diversity and possible applications of synthesized molecules. The extension of developed method resulted in the synthesis of novel: tricyclic 5,10-dihydrobenzo[b]thieno[3,4-f][1,4]diazocine-4,11-dione scaffold and fused pentacyclic framework possessing two benzodiazocine rings within its structure. Additionally, the unprecedented rearrangement of 5,12-dihydrodibenzo[b,f][1,4]diazocine-6,11-diones to 2-(2-aminophenyl)isoindoline-1,3-diones was observed under the basic conditions in the presence of sodium hydride for secondary dilactams. The structures of nine synthesized products have been established by single-crystal X-ray diffraction analysis. Detailed crystallographic analysis of the investigated tri- and pentacyclic systems has shed more light on their structural features. One cell line derived from non-cancerous cells (EUFA30—human fibroblasts) and three tumor cells (U87—human primary glioblastoma, HeLa—cervix adenocarcinoma, BICR18—laryngeal squamous cell carcinoma) were used to determine the cytotoxic effect of the newly synthesized compounds. Although these compounds showed a relatively weak cytotoxic effect, the framework obtained for 5,12-dihydrodibenzo[b,f][1,4]diazocine-6,11-dione could serve as a convenient privilege structure for the design and development of novel bioactive molecules suitable for drug design, development and optimization programs.
Indoloquinoxaline derivatives as promising multi-functional anti-Alzheimer agents
Kanhed, Ashish M.,Patel, Dushyant V.,Patel, Kirti V.,Patel, Kishan B.,Patel, Nirav R.,Prajapati, Navnit K.,Sinha, Anshuman,Thakor, Priyanka S.,Yadav, Mange Ram
, (2020/11/02)
To confront a disease like Alzheimer’s disease having complex pathogenesis, development of multitarget-directed ligands has emerged as a promising drug discovery approach. In our endeavor towards the development of multitarget-directed ligands for Alzheimer’s disease, a series of indoloquinoxaline derivatives were designed and synthesized. In vitro cholinesterase inhibition studies revealed that all the synthesized compounds exhibited moderate to good cholinesterase inhibitory activity. 6-(6-(Piperidin-1-yl)hexyl)-6H-indolo[2,3-b]quinoxaline 9f was identified as the most potent and selective BuChE inhibitor (IC50 = 0.96 μM, selectivity index = 0.17) that possessed 2 fold higher BuChE inhibitory activity compared to the commercially approved reference drug donepezil (IC50 = 1.87 μM). Moreover, compound 9f is also endowed with self-induced Aβ1-42 aggregation inhibitory activity (51.24% inhibition at 50 μM concentration). Some of the compounds of the series also displayed moderate anti-oxidant activity. To perceive a putative binding mode of the compound 9f, molecular docking studies were carried out, and the results pointed out significant interactions of compound 9f with the enzymes in the binding sites of cholinesterases as well as Aβ1-42. Additionally, compound 9f exhibited favorable in silico ADMET properties. Put together these findings project compound 9f as a potential multitarget-directed ligand in the direction of developing novel anti-AD drugs. Communicated by Ramaswamy H. Sarma.
