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61.
Kriti Pathak Sourav Gayen Suvam Saha Chandan Nandi Shivankan Mishra Prof. Dr. Sundargopal Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(18):e202104393
Treatment of [Cp*RuCl2]2, 1 , [(COD)IrCl]2, 2 or [(p-cymene)RuCl2]2, 3 (Cp*=η5-C5Me5, COD= 1,5-cyclooctadiene and p-cymene=η6-iPrC6H4Me) with heterocyclic borate ligands [Na[(H3B)L], L1 and L2 ( L1 : L=amt, L2 : L=mp; amt=2-amino-5-mercapto-1,3,4-thiadiazole, mp=2-mercaptopyridine) led to the formation of borate complexes having uncommon coordination. For example, complexes 1 and 2 on reaction with L1 and L2 afforded dihydridoborate species [LAM(μ-H)2BHL] 4 – 6 ( 4 : LA=Cp*, M=Ru, L=amt; 5 : LA=Cp*, M=Ru, L=mp; 6 : LA=COD, M=Ir, L=mp). On the other hand, treatment of 3 with L2 yielded cis- and trans-bis(dihydridoborate) species, [Ru{(μ-H)2BH(mp)}2], cis- 7 and trans- 7 . The isolation and structural characterization of fac- and mer-[Ru{(μ-H)2BH(mp)}{(μ-H)BH(mp)2}], 8 from the same reaction offered an insight into the behaviour of these dihydridoborate species in solution. Fascinatingly, despite having reduced natural charges on Ru centres both at cis-and trans- 7 , they underwent hydroboration reaction with alkynes that yielded both Markovnikov and anti-Markovnikov addition products, 10 a – d . 相似文献
62.
Bhardwaj Hema Singh Chandan Kotnala R. K. Sumana Gajjala 《Analytical and bioanalytical chemistry》2018,410(28):7313-7323
Analytical and Bioanalytical Chemistry - Due to the similar electrochemical properties to graphene oxide (GO), graphene quantum dots (GQDs) are considered as a highly potential candidate for... 相似文献
63.
M. Bidya Sagar K. Ravikumar S. Mehdi Y.S. Sadanandam K.T. Giju E.D. Jemmis 《Journal of chemical crystallography》1999,29(4):481-491
A series of 4(x-substituted phenyl)-1,4-dihydropyridines (x=2—CF3 (1), 2-CH3 (2), 2-OCH3 (3) and 2,4-Cl (4)) with a new substituent, the N-methylcarbamoyl (CONHCH3) group at C3 and C5 are crystallographically characterized and a comparison has been made with important conformational parameters obtained theoretically. The dihydropyridine rings are in shallow boat conformation. The phenyl substituent orientation is synperiplanar. Both the carbonyl groups are oriented anticlinal in 1, 2 and 3; but in 4, one is synclinal and the other synperiplanar with the adjacent double bond. The presence of solvent molecules in 1 (CH3OH), 2 (CH3OH), and 3 (H2O) has significantly changed the hydrogen bonding pattern. Theoretical studies at the semiempirical AM1 MO level reproduces the general features of the structures. The near planarity of the DHP ring and the orientation of the phenyl substituent make 1 and 2 encouraging targets for pharmacological, study. Crystallographic Data:1: a = 8.793(2), b = 29.962(5), c = 8.215(2) Å, = 115.28(2)°, Monoclinic, P21/c;
2: a = 8.799(2), b = 15.789(3), c = 14.074(2) Å, = 100.25(2)°, Monoclinic, P21/n; 3: a = 8.347(1), b = 8.986(1), c = 13.749(2) Å, = 97.50(1), = 94.78(1), = 101.38(1)° Triclinic, P1¯4: a = 12.928(3), b = 14.506(3), c = 9.740(2) Å, Orthorhombic, Pca21. 相似文献
64.
The solid state structures of two dihydropyrimidines (DHPM) viz, 2-[(4-dimethylamino)phenyl]-1-phenethyl-2,3-dihydro-1H-quinazolin-4-one (compound 1) and 1-phenethyl-2p-tolyl-2,3-dihydro-1H-quinazolin-4-one (compound 2) are reported here. The compound 1 belongs to triclinic (P-1) space group with cell parameters a = 7.4314(12) Å, b = 9.9747(16) Å, c = 14.658(2) Å, = 104.142(3), = 102.584(3), = 98.188(3). The compound 2 also belongs to triclinic (P-1) space group with cell parameters a = 9.8707(11) Å, b = 9.9225(11) Å, c = 10.7425(13) Å, = 79.227(2), = 80.568(2), = 63.649(2). The structures show that the substituent at 2-position will play a key role in defining the pyrimidine ring conformation. The central dihydropyrimidine ring in both the structures are affected by conjugation. The sum of the valence angles around all the nitrogens is very close to 360, indicating that the state of hybridization of these atoms is sp2. The DHP ring is puckered in such a manner that the atoms N1, C3, C4, C5, and N2 are coplanar and the sixth atom C2 is displaced 0.605 Å (0.18 Å for compound 2) above the least squares plane. The conformation of dihydropyrimidine ring can be described as a sofa with asymmetric parameters Cs[C2] = 6.09 (compound 1) and 4.73 (compound 2), respectively. The phenethyl group has a fully extended conformation with respect to the central pyrimidine ring (N2–C16–C17–C18 174.8(2) and 179.1(6) for compounds 1 and 2, respectively). The substituents on the DHPM ring, dimethylamino-phenyl/p-tolyl groups of compound 1/2 occupy equatorial/axial positions at C2. In the crystal packing, six membered rings form through dimerization using N–HO hydrogen bonding. 相似文献
65.
2,2,5-Trisubstituted pyrrolidines are available from allylic pyroglutamates by Ireland-Claisen ester rearrangement followed by Eschenmoser sulfide contraction and reduction in a highly diastereoselective and efficient sequence. Some of the products from this sequence exhibit activity against S. aureus, but are much less active against E. coli. 相似文献
66.
Maity J Shakya G Singh SK Ravikumar VT Parmar VS Prasad AK 《The Journal of organic chemistry》2008,73(14):5629-5632
Candida antarctica lipase-B (CAL-B) immobilized on lewatite selectively acylated the primary hydroxyl group of the furanosyl nucleoside in a mixture of 1-(alpha-D-arabinofuranosyl)thymine and 1-(alpha-D-arabinopyranosyl)thymine. This selective biocatalytic acylation of furanosyl nucleoside has enabled us an easy separation of arabinofuranosyl thymine from an inseparable mixture with arabinopyranosyl thymine. The primary hydroxyl selective acylation methodology of arabinonucleoside has also been successfully used for the separation of 1-(beta-D-xylofuranosyl)thymine and 1-(beta-D-xylopyranosyl)thymine from a mixture of the two, which demonstrate the generality of the enzymatic methodology for separation of furanosyl and pyranosyl nucleosides. 相似文献
67.
Dr. Ravikumar Jimmidi 《European journal of organic chemistry》2023,26(18):e202300028
Peptides are described as naturally occurring short chains of amino acids and offer great potential as therapeutic agents because of their target selectivity, safe, and well tolerable. Hence, there is an increased interest in peptides in pharmaceutical research and development and approximately more than 170 peptide therapeutics are currently being evaluated in clinical trials and many are being used as therapeutic drugs for various diseases including COVID-19. The present Review article focuses on recent progress in peptide drug discovery and advancements in synthetic methodologies to enhance their stability and physiological activity of peptides and as well peptidomimetics. 相似文献
68.
We present a comparative study of nucleon structure such as electromagnetic form factors, transverse charge and magnetization densities in three different models within AdS/QCD framework. 相似文献
69.
70.
Podder Soumik Halder Suman Roychowdhury Anirban Das Dipankar Ghosh Chandan Kr. 《Journal of nanoparticle research》2016,18(10):1-13
Journal of Nanoparticle Research - With the widespread use of titanium dioxide (TiO2) human exposure is inevitable, but the exposure data on TiO2 are still limited. This study adopted off-line... 相似文献