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141.
Pritam Dolui Vikas Tiwari Parul Saini Dr. Tarak Karmakar Koushik Makhal Harshita Goel Dr. Anil J. Elias 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(43):e202200829
An efficient, metal-free, catalyst-free and solvent-free methodology for the reductive amination of levulinic acid with different anilines has been developed using HBpin as the reducing reagent. This protocol offers an excellent method to avoid solvents and added catalysts on the synthesis of different kinds of N-substituted pyrrolidones under metal free conditions. It is also the first report for the synthesis of different pyrrolidones by solvent-free as well as catalyst-free methods. The proposed mechanism for the formation of pyrrolidone has been supported by DFT calculations and control experiments. 相似文献
142.
Shyam Sundar Mondal Namita Jaiswal Partha Sarathi Bera Ranjay K. Tiwari Jogendra Nath Behera Nripen Chanda Subhas Ghosal Tanmoy Kumar Saha 《应用有机金属化学》2021,35(1)
A series of copper (II) ( 1 and 3 ) and cobalt (II/III) ( 2 , 4 and 5 ) complexes comprising different imino‐phenolate ligands DCH , DTH and DBH 2 (where DCH = 2,4‐dichloro‐6‐((mesitylimino)methyl)phenol, DTH = 2,4‐di‐tert‐butyl‐6‐((mesitylimino)methyl) phenol and DBH 2 = 2,4‐dibromo‐6‐((mesitylimino)methyl)phenol) have been prepared with excellent yield and high purity. By utilizing different spectroscopic tools such as UV–visible, electrospray ionization (ESI)‐mass, Fourier‐transform infrared (FTIR) spectrometry and elemental analysis, the prepared complexes ( 1 – 5 ) were thoroughly characterized. The molecular structure of the synthesized complexes was ascertained by using single‐crystal X‐ray diffraction studies (SCXRDs). The experiment reveals that Complexes 1 – 5 bind to calf thymus DNA (CT‐DNA) through non‐intercalative way with good interacting abilities. However, 1 – 5 are excellent quenchers of the fluorescence intensity of bovine serum albumin (BSA) following the static pathway. Additionally, they had shown remarkable cytotoxic potential against MCF‐7 (mammary gland adenocarcinoma) and A549 (lung adenocarcinoma) cell lines. The IC50 values associated with these complexes were much lower than the conventional drug cisplatin. Apoptosis‐induced cell death was confirmed from the DNA fragmentation studies and Hoechst 33342 staining. The 2′,7′‐dichlorofluorescein diacetate (DCFDA) assay indicates that the complex mediated reactive oxygen species (ROS) generation is accountable for governing the apoptosis mechanism via oxidative cell distress. Apart from these studies, by carrying out density functional theory (DFT) method, highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) energy gap calculations and optimized structures of the synthesized complexes were accomplished. 相似文献
143.
Heteroatom‐Guided,Palladium‐Catalyzed,Site‐Selective CH Arylation of 4H‐Chromenes: Diastereoselective Assembly of the Core Structure of Myristinin B through Dual CH Functionalization 下载免费PDF全文
Govind Goroba Pawar Virendra Kumar Tiwari Dr. Himanshu Sekhar Jena Dr. Manmohan Kapur 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9905-9911
A highly site‐selective, heteroatom‐guided, palladium‐catalyzed direct arylation of 4H‐chromenes is reported. The C?H functionalization is driven not only by the substituents and structure of the substrate but also by the coupling partner being used. The diastereoselective assembly of the core structure of Myristinin B has been achieved by using a dual C?H functionalization strategy for regioselective direct arylation. 相似文献
144.
145.
Shovon Chatterjee Pritam Dey Nilimesh Das Khushubo Tiwari Dr. Tanmoy Maiti Prof. Pratik Sen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(7):1506-1510
An ultra-slow crystal growth over a period of 24 h of a newly synthesized CH3NH3Pb1/2Bi1/3I3 perovskite (MPBI) nanocrystal in non-polar toluene medium is reported here. From several spectroscopic techniques as well as from TEM analysis we found that the size of nanocrystals changes continuously with time, in spite of being capped by the ligands. Using a single molecular spectroscopic technique, we also found that this size change is not due to the stacking of nanocrystals but due to crystal growth. The notable temperature dependence and reversible nature of the nanocrystals growth is explained by the dynamic nature of the capping. The observed temperature-dependent ultra-slow growth is believed to be a pragmatic step towards controlling the size of perovskite NC in a systematic manner. 相似文献
146.
147.
Thin and surface adhesive ferroelectric poly(vinylidene fluoride) films with β phase‐inducing amino modified porous silica nanofillers 下载免费PDF全文
Vimal K. Tiwari Ravindra V. Ghorpade Kang Lib Kim Giyoung Song Taehee Kim Haksoo Han Cheolmin Park 《Journal of Polymer Science.Polymer Physics》2016,54(23):2401-2411
We report an efficient route for ferroelectric polar β phase generation in poly(vinylidene fluoride) (PVDF) through incorporation of amine functionalized, porous silica (MCM‐41 and fumed silica) based nanofillers. These porous highly functionalized surfaces exhibit the efficient secondary interaction with polymer chain via hydrogen bonding. Structural analysis through FTIR, XRD, and TEM confirm high degree of ferroelectric polar β phase generation of PVDF through incorporation of amino modified porous silica nanofillers. Optimized loading (5 wt %) of amine functionalized, porous silica in PVDF matrix enhances relative intensity of β phase up to 75%. Disappearance of spherulite structure of PVDF with amino modified porous silica nanofillers, as confirmed through POM, TEM, SEM and AFM studies also supports the above conclusion. The P‐E hysteresis loop at sweep voltage of ±50 V of a thin PVDF‐amino modified porous nanofiller film shows excellent ferroelectric property with nearly saturated high remnant polarization 2.8 µC.cm?2 owing to its large proportion of β PVDF, whereas, a nonpolar pure PVDF thin film shows unsaturated hysteresis loop with 0.6 µC.cm?2 remnant polarization. PVDF films with the nanofillers exhibit strong adhesive strength over different metallic substrates making them have edge over PVDF in various thin film applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 2401–2411 相似文献
148.
149.
A series of dihydropyranochromenes and chromenopyrimidine-2,5-diones having chromene scaffold were synthesized via efficient multicomponent protocol in aqueous β-cyclodextrin. The reaction is free of toxic solvents, operating under mild conditions and allows for ease of product isolation, making it more environmentally friendly. All the synthesized compounds biologically evaluated for their potential inhibitory effect on both cervical cancer cell line (HeLa) and human breast adenocarcinoma cell line (MCF-7). Of these compounds, 4d was found to be the most potent inhibitors of HeLa and MCF-7 demonstrating IC50 values of 19?µM and 7?µM. Compounds 4b, 4e and 4f also shown significantly good in vitro anticancer activity against HeLa and MCF-7 cancer cell lines. 相似文献
150.
Jyoti Tiwari Swastika Singh Mohammad Saquib Fatima Tufail Amit Kumar Sharma Shailesh Singh 《合成通讯》2018,48(2):188-196
The discovery of a new L-valine promoted facile and versatile green synthesis of diversified 2-amino-3-cyano-4H-pyrans using a one pot multicomponent-tandem reaction of aromatic aldehydes, malononitrile, and diverse electron-rich enolizable carbonyl compounds is described. To the best of our knowledge this is the first report on the use of native L-valine as a catalyst in organic synthesis. Environmental friendly, mild reaction conditions, use of easily available inexpensive starting materials, short reaction time, excellent yields, high atom economy, and recyclability of organocatalyst are the major advantages of the disclosed protocol. 相似文献