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1.
Ravula Sharada Nukala Satheesh Kumar Thirukovela Narasimha Swamy Sirassu Narsimha Dasari Gouthami Kurma Srimathi Bandari Srinivas 《Russian Journal of General Chemistry》2022,92(4):702-708
Russian Journal of General Chemistry - In the current study, some new quinoxaline linked 1,3,4-oxadiazole sulfonamide hybrids have been designed, synthesized and characterized by IR, 1H and 13C... 相似文献
2.
Formation of 1-aryl-4-oxo-cyclohexa(e)nonecarboxylates from the Diels–Alder cycloaddition of 2-trimethylsilyloxy-1,3-butadiene and Danishefsky diene with aryl- and pyridylacrylates and further conversion thereof to spirocycles is described. This provides an efficient method for spiro oxindoles, azaoxindoles, and dihydroisoquinolones.
3.
Dr. Srivari Chandrasekhar Kakita Veera Mohana Rao Mallikanti Seenaiah Police Naresh Ambure Sharada Devi Dr. Bharatam Jagadeesh 《化学:亚洲杂志》2014,9(2):457-461
Hybrid peptidic oligomers comprising natural and unnatural amino acid residues that can exhibit biomolecular folding and hydrogen‐bonding mimicry have attracted considerable interest in recent years. While a variety of hybrid peptidic helices have been reported in the literature, other secondary structural patterns such as γ‐turns and ribbons have not been well explored so far. The present work reports the design of novel periodic γ‐turns in the oligomers of 1:1 natural‐α/unnatural trans‐β‐norborenene (TNAA) amino acid residues. Through DFT, NMR, and MD studies, it is convincingly shown that, in the mixed conformational pool, the heterogeneous backbone of the hybrid peptides preferentially adopt periodic 8‐membered (pseudo γ‐turn)/7‐membered (inverse γ‐turn) hydrogen bonds in both polar and non‐polar solvent media. It is observed that the stereochemistry and local conformational preference of the β‐amino acid building blocks have a profound influence on accessing the specific secondary fold. These findings may be of significant relevance for the development of molecular scaffolds that facilitate desired positioning of functional side‐chains. 相似文献
4.
Kristopher M. Koskela Stephen J. Quiton Shaama Mallikarjun Sharada Travis J. Williams Richard L. Brutchey 《Chemical science》2022,13(11):3208
Oxide dissolution is important for metal extraction from ores and has become an attractive route for the preparation of inks for thin film solution deposition; however, oxide dissolution is often kinetically challenging. While binary “alkahest” systems comprised of thiols and N-donor species, such as amines, are known to dissolve a wide range of oxides, the mechanism of dissolution and identity of the resulting solute(s) remain unstudied. Here, we demonstrate facile dissolution of both bulk synthetic and natural mineral ZnO samples using an “alkahest” that operates via reaction with thiophenol and 1-methylimidazole (MeIm) to give a single, pseudotetrahedral Zn(SPh)2(MeIm)2 molecular solute identified by X-ray crystallography. The kinetics of ZnO dissolution were measured using solution 1H NMR, and the reaction was found to be zero-order in the presence of excess ligands, with more electron withdrawing para-substituted thiophenols resulting in faster dissolution. A negative entropy of activation was measured by Eyring analysis, indicating associative ligand binding in, or prior to, the rate determining step. Combined experimental and computational surface binding studies on ZnO reveal stronger, irreversible thiophenol binding compared to MeIm, leading to a proposed dissolution mechanism initiated by thiol binding to the ZnO surface with the liberation of water, followed by alternating MeIm and thiolate ligand additions, and ultimately cleavage of the ligated zinc complex from the ZnO surface. Design rules garnered from the mechanistic insight provided by this study should inform the dissolution of other bulk oxides into inks for solution processed thin films.Oxide dissolution is important for metal extraction from ores and has become an attractive route for the preparation of inks for thin film solution deposition; however, oxide dissolution is often kinetically challenging. 相似文献
5.
Aryne‐Induced Novel Tandem 1,2‐Addition/(3+2) Cycloaddition to Generate Imidazolidines and Pyrrolidines
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Dr. Sharada P. Swain Yi‐Chun Shih Dr. Shwu‐Chen Tsay Joby Jacob Dr. Chun‐Cheng Lin Dr. Kuo Chu Hwang Dr. Jia‐Cherng Horng Prof. Dr. Jih Ru Hwu 《Angewandte Chemie (International ed. in English)》2015,54(34):9926-9930
A new “single‐flask” method was developed for the synthesis of imidazolidines and pyrrolidines with high stereoselectivity. First, a Schiff base was arylated with an aryne. Second, an intramolecular proton transfer took place from the methylene position to the anionic aryne ring. Third, the resultant ylide reacted with a second equivalent of the same Schiff base in situ or an electron‐deficient alkene through a (3+2) cycloaddition. These sequential tandem 1,2‐addition/(3+2) cycloaddition reactions led to the desired heterocycles in 63–88 % yields. 相似文献
6.
Kuppuswamy Nagarajan Sharada J. Shenoy Hans Fritz Othmar Hosang Wilhelm J. Richter 《Helvetica chimica acta》1985,68(4):900-902
The reaction of anthranilamide with phosphorus pentasulfide in boiling pyridine leads to the benzodiazaphosphorine-pyridine salt 2 . The structure is established by elemental analysis, 1H- 13C- 15N- 31P-NMR, and mass spectral data. 相似文献
7.
Aparna Y. Sharada L. N. Subhashini N. J. P. Sreekanth Sivan 《Russian Journal of General Chemistry》2019,89(6):1202-1208
Russian Journal of General Chemistry - The title compounds are synthesized by condensation of 2-[4-(arylidene)-5-oxo-4, 5-dihydrooxazol-2-yl]phenylacetate with aromatic amines in presence of the... 相似文献
8.
The growth of single crystals of acetoacetanilide using slow evaporation technique is reported. Good-quality crystals up to a size of 20×10×1 mm3 are obtained. The grown crystals are characterized by employing UV-VIS spectrum, IR spectrum, and hardness measurements. Acetoacetanilide shows very good second-harmonic generation (SHG) efficiency. 相似文献
9.
Sharada L. N. Sunitha S. N. T. Sabha Maryam Viveka T. L. Aparna Y. Prasad M. 《Research on Chemical Intermediates》2020,46(7):3341-3360
Research on Chemical Intermediates - The present work focused on the assembly of 2-((2-(4-chlorophenylamino)phenylimino)methyl)-6-methoxyphenol as primary ligand (VBL) and bidentate nitrogen... 相似文献
10.
The organo-base, 1,1,3,3-tetramethylguanidine, mediates the Cannizzaro reaction of reactive aromatic aldehydes in water thus providing the corresponding alcohols and acids. Application of formaldehyde as a sacrificial aldehyde for the cross-Cannizzaro reaction is also presented. 相似文献