02052nas a2200265 4500008004100000022001400041245015900055210006900214260007300283300001000356490000900366520105300375653001601428653002001444653000801464653002101472653001201493653003201505100002701537700002101564700001901585700002601604700002601630856013001656 2012 eng d a0022-286000aSingle crystal X-ray structure of lawsone anion: evidence for coordination of alkali metal ions and formation of naphthosemiquinone radical in basic media0 aSingle crystal Xray structure of lawsone anion evidence for coor aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB a38-450 v10103 a

2-hydroxy-1,4-naphthoquinone; Lawsone (Lw) is a natural compound found in henna leaves. The reaction of lawsone with `Na' metal (Lw-1), CH3COONa (Lw-2), NaOH (Lw-3), KOH (Lw-4), K2CO3 (Lw-5) and Tris(hydroxymethyl)aminomethane (Lw-6) were studied. Red orange solids obtained for Lw-1 to Lw-6 are characterized by Elemental Analysis, FTIR, (HNMR)-H-1 and EPR studies. The results reveal the coordination of alkali metals `Na' and `K' to lawsone anion. The single crystal X-ray structure of Lw-6 was solved and it crystallizes in triclinic space group P-1 with extensive hydrogen bonding network of C-H center dot center dot center dot O, N-H center dot center dot center dot O and O-H center dot center dot center dot O between cations and anions. Polycrystalline powder X-band EPR spectra of Lw-1 to Lw-5 shows signals similar to 2.004 at 133 K, while Lw-6 is EPR silent. The naphthosemiquinone (NSQ) radical formed in Lw-2 to Lw-5, is due to disproportion reaction of catechol and naphthoquinone. (C) 2011 Elsevier B.V. All rights reserved.

10a2-Hydroxy-110a4-naphthoquione10aEPR10ahydrogen bonding10aLawsone10aNaphthosemiquinone radicals1 aSalunke-Gawali, Sunita1 aKathawate, Laxmi1 aShinde, Yogesh1 aPuranik, Vedavati, G.1 aWeyhermueller, Thomas uhttps://library.ncl.res.in/content/single-crystal-x-ray-structure-lawsone-anion-evidence-coordination-alkali-metal-ions-and-003604nas a2200385 4500008004100000022001400041245019700055210006900252260006700321300001200388490000700400520219800407653001002605653001202615653002402627653000902651653002102660653000802681653004902689653002602738653004602764653000902810653002702819653002202846100002302868700002302891700003402914700002502948700002002973700002202993700002403015700002603039700002403065856012903089 2013 eng d a1747-027700aDesign, synthesis, structural characterization by IR, 1H, 13C, 15N, 2D-NMR, X-ray diffraction and evaluation of a new class of phenylaminoacetic acid benzylidene hydrazines as pfENR inhibitors0 aDesign synthesis structural characterization by IR 1H 13C 15N 2D a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcJUN a715-7290 v813 a

Recent studies have revealed that plasmodial enoyl-ACP reductase (pfENR, FabI), one of the crucial enzymes in the plasmodial type II fatty acid synthesis II (FAS II) pathway, is a promising target for liver stage malaria infections. Hence, pfENR inhibitors have the potential to be used as causal malarial prophylactic agents. In this study, we report the design, synthesis, structural characterization and evaluation of a new class of pfENR inhibitors. The search for inhibitors began with a virtual screen of the iResearch database by molecular docking. Hits obtained from the virtual screen were ranked according to their Glide score. One hit was selected as a lead and modified to improve its binding to pfENR; from this, a series of phenylamino acetic acid benzylidene hydrazides were designed and synthesized. These molecules were thoroughly characterized by IR, 1H, 13C, 15N, 2D-NMR (COSY, NOESY, 1H-13C, 1H-15N HSQC and HMBC), and X-ray diffraction. NMR studies revealed the existence of conformational/configurational isomers around the amide and imine functionalities. The major species in DMSO solution is the E, E form, which is in dynamic equilibrium with the Z, E isomer. In the solid state, the molecule has a completely extended conformation and forms helical structures that are stabilized by strong hydrogen bond interactions, forming a helical structure stabilized by N-H...O interactions, a feature unique to this class of compounds. Furthermore, detailed investigation of the NMR spectra indicated the presence of a minor impurity in most compounds. The structure of this impurity was deduced as an imidazoline-4-one derivative based on 1H-13C and 1H-15H HMBC spectra and was confirmed from the NOESY spectra. The molecules were screened for in vitro activity against recombinant pfENR enzyme by a spectrophotometric assay. Four molecules, viz. 17, 7, 10, and 12 were found to be active at 7, 8, 10, and 12m concentration, respectively, showing promising pfENR inhibitory potential. A classification model was derived based on a binary QSAR approach termed recursive partitioning (RP) to highlight structural characteristics that could be tuned to improve activity.

10aADMET10adocking10aenoyl-ACP reductase10aFabI10ahydrogen bonding10aNMR10aphenylaminoacetic acid benzylidene hydrazine10aPlasmodium falciparum10aPlasmodium falciparum enoyl-ACP reductase10aQSAR10arecursive partitioning10aX-ray diffraction1 aSamal, Ramanuj, P.1 aKhedkar, Vijay, M.1 aPissurlenkar, Raghuvir, R. S.1 aBwalya, Angela, Gono1 aTasdemir, Deniz1 aJoshi, Ramesh, A.1 aRajamohanan, P., R.1 aPuranik, Vedavati, G.1 aCoutinho, Evans, C. uhttps://library.ncl.res.in/content/design-synthesis-structural-characterization-ir-1h-13c-15n-2d-nmr-x-ray-diffraction-and-002297nas a2200289 4500008004100000022001400041245009400055210006900149260007300218300001200291490000900303520131100312653002101623653001901644653001401663653002301677653001601700653001701716100002101733700002201754700001701776700001901793700002301812700002601835700002701861856011901888 2013 eng d a0022-286000aSynthesis and molecular structure of a zinc complex of the vitamin K-3 analogue phthiocol0 aSynthesis and molecular structure of a zinc complex of the vitam aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP a223-2290 v10483 a

The complex [Zn(phthiocol)(2)(H2O)(2)]; 1, where phthiocol is 2-hydroxy-3-methyl-1,4-naphthoquinone, has been synthesized and characterized by elemental analysis, FT-IR, H-1 NMR, UV-vis spectroscopy, thermogravimetric (TG) analysis, electrochemical and single crystal X-ray diffraction studies. The v(C=O) stretch shifts to lower frequencies upon complexation of phthiocol to Zn2+. H-1 NMR spectra show an upfield shift of the benzenoid ring protons in 1. There is a bathochromic shift of the LMCT band in the UV-vis spectra of 1. Single crystal X-ray structure of 1 show distorted octahedral geometry around Zn2+. Two phthiocol ligands are in plane with the metal, while water molecules are trans to this plane. Coordination of deprotonated phthiocol ligands is `trans, trans' to Zn2+. Intra as well as intermolecular interactions are observed in 1. Molecules of 1 show three dimensional network through C-H center dot center dot center dot O and O-H center dot center dot center dot O interactions. Additional anodic peaks are observed in cyclic voltammogram of phthiocol ligand due to oxidation of reduced species formed during reduction. One-electron reduction of 1 is shown to be reversible and DFT studies define this redox event as ligand-centered. (c) 2013 Elsevier B.V. All rights reserved.

10ahydrogen bonding10aNaphthoquinone10aPhthiocol10aTrans coordination10aVitamin K-310aZinc complex1 aKathawate, Laxmi1 aSproules, Stephen1 aPawar, Omkar1 aMarkad, Ganesh1 aHaram, Santosh, K.1 aPuranik, Vedavati, G.1 aSalunke-Gawali, Sunita uhttps://library.ncl.res.in/content/synthesis-and-molecular-structure-zinc-complex-vitamin-k-3-analogue-phthiocol-002519nas a2200301 4500008004100000022001400041245012600055210006900181260007300250300001100323490000900334520145600343653000601799653001601805653002101821653002401842653002101866653002101887653001901908100002701927700001701954700002001971700002101991700002602012700002602038700002802064856012502092 2014 eng d a0022-286000aSynthesis, characterization and molecular structures of homologated analogs of 2-bromo-3-(n-alkylamino)-1,4-napthoquinone0 aSynthesis characterization and molecular structures of homologat aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN a97-1030 v10563 a

Four analogues of 2-bromo-3-(n-alkylamino)-1,4-napthoquinone (where n-alkyl is methyl in L-1Br, ethyl in L-2Br, propyl in L-3Br and butyl in L-4Br) are synthesized and characterized. A reaction mechanism is proposed for the formation of L-1 Br to L-4Br from the starting material 2,3-dibromo-1,4-naphthoquinone. The v(N-H) frequency in the FT-IR spectra is affected by the intramolecular hydrogen bonding in L-1Br to L-4Br and is observed similar to 3267 cm(-1) in L-2Br. A shift of similar to 25 cm(-1) is observed in the v(C-Br) frequency in all the compounds as compared to 2,3-dibromo-1,4-naphthoquinone (627 cm(-1)). A broad charge transfer band is observed between 400 and 600 nm in the UV-Vis spectra, which imparts red colour to all the compounds. Molecular structures of L-2Br and L-3Br were studied by single crystal X-ray diffraction studies. Molecules of L-2Br crystallize in Pca2(1), whereas the molecule L-3Br crystallizes in the P-1 space group. Molecules of L-2Br forms a polymeric chain through N-H...O interaction and forms beautiful butterfly like arrangement of molecules when viewed down the `a' axis. Ladder like polymeric chain of molecules is observed in L-3Br via C-H...O and N-H...O interactions. Every alternating neighbouring chains of L-3Br, show pi-pi stacking interactions between the quinonoid rings of the molecules, however this interaction is not observed in L-2Br. (C) 2013 Elsevier B.V. All rights reserved.

10a210a3-Dibromo-110a4-naphthoquinone10aAminonaphthoquinone10ahydrogen bonding10aMichael addition10api-pi stacking1 aSalunke-Gawali, Sunita1 aPawar, Omkar1 aNikalje, Milind1 aPatil, Rishikesh1 aWeyhermueller, Thomas1 aPuranik, Vedavati, G.1 aKonkimalla, Badireenath uhttps://library.ncl.res.in/content/synthesis-characterization-and-molecular-structures-homologated-analogs-2-bromo-3-n-002215nas a2200277 4500008004100000022001400041245010800055210006900163260007300232300001000305490000900315520124800324653001301572653000801585653002101593653002301614653001401637653001501651100002101666700002401687700002201711700002301733700002601756700002701782856012801809 2015 eng d a0022-286000aFirst naphthosemiquinone complex of K+ with vitamin K3 analog: experiment and density functional theory0 aFirst naphthosemiquinone complex of K with vitamin K3 analog exp aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY a56-630 v10883 a

Synthesis and characterization of potassium complex of 2-hydroxy-3-methyl-1,4-naphthoquinone (phthiocol), the vitamin K3 analog, has been carried out using FT-IR, UV-Vis, H-1 and C-13 NMR, EPR, cyclic voltammetry and single crystal X-ray diffraction experiments combined with the density functional theory. It has been observed that naphthosemiquinone binds to two K+ ions extending the polymeric chain through bridging oxygens O(2) and O(3). The crystal network possesses hydrogen bonding interactions from coordinated water molecules showing water channels along the c-axis. C-13 NMR spectra revealed that the complexation of phthiocol with potassium ion engenders deshielding of C(2) signals, which appear at delta = similar to 14.6 ppm whereas those of C(3) exhibit up-field signals near delta similar to 6.9 ppm. These inferences are supported by the M06-2x based density functional theory. Electrochemical experiments further suggest that reduction of naphthosemiquinone results in only a cathodic peak from catechol. A triplet state arising from interactions between neighboring phthiocol anion lead to a half field signal at g = 4.1 in the polycrystalline X-band EPR spectra at 133 K. (C) 2015 Elsevier B.V. All rights reserved.

10aC-13 NMR10aDFT10ahydrogen bonding10aNaphthosemiquinone10aPhthiocol10aVitamin K31 aKathawate, Laxmi1 aGejji, Shridhar, P.1 aYeole, Sachin, D.1 aVerma, Prakash, L.1 aPuranik, Vedavati, G.1 aSalunke-Gawali, Sunita uhttps://library.ncl.res.in/content/first-naphthosemiquinone-complex-k-vitamin-k3-analog-experiment-and-density-functional-0