02831nas a2200289   4500008004100000022001400041245013800055210006900193260007300262300001000335490000900345520178500354653002402139653002402163653000902187653002302196653001902219100001702238700002102255700002102276700002102297700002302318700001902341700002602360700002702386856012802413       2014                        eng d  a0022-286000aMolecular structures and biological evaluation of 2-chloro-3-(n-alkylamino)-1,4-napthoquinone derivatives as potent antifungal agents0 aMolecular structures and biological evaluation of 2chloro3nalkyl  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB  a68-740 v10593 a<p>Derivatives of 2-chloro-3-(n-alkylamino)-1,4-naphthoquinone (1-alkyl: methyl; L-1, ethyl; L-2, propyl; L-3 and butyl; L-4) have been synthesized and characterized by elemental analysis, FT-IR, H-1 NMR, UV-visible spectroscopy, LC-MS and single crystal X-ray diffraction studies. Antifungal activity of L-1 to L-4 has been evaluated against Candida tropicalis, Candida albicans and Cladosporium herbarum. The intramolecular hydrogen bonding affects the N-H vibrational frequency in L-2 (3273 cm(-1)). The single crystal X-ray structure reveal that L-1 and L-3 crystallizes in triclinic P-1, whereas L-2 crystallizes in orthorhombic Pca2(1), space group. An extensive intra and intermolecular hydrogen bonding interactions were observed in L-1 to L-3 which leads to molecular association. Intramolecular N-H center dot center dot center dot O hydrogen bonding were observed in L-1 to L-3. Moreover pi-pi stacking interactions were observed between the quinonoid rings of L-1 and L-3, however no such interactions were observed in L-2. An electrochemical study showed molecular association of L-1 to L-4 in DMSO solution. Compounds L-1 to L-4 were found to be potent antifungal agents against all the three strains, especially against C. tropicalis. Amongst these promising antifungal candidates, L-1 showed better activity compared to the clinically administered antifungal drug Amphotericin B and Nitrofurantoin with MIC = 1.25 mu g ml(-1) and MIC = 0.025 mu g ml(-1) respectively against C. albicans. Structure and activity relationship (SAR) study suggest a LogP value of similar to 2.0 and the cyclic voltammetry studies reveals additional chemical processes for L-1, which exhibits maximum activity against all fungal strains. (C) 2013 Elsevier B.V. All rights reserved.</p>10aAminonaphthoquinone10aAntifungal activity10aLogP10aNaphthosemiquinone10api-pi stacking1 aPawar, Omkar1 aPatekar, Ashwini1 aKhan, Ayesha, A.1 aKathawate, Laxmi1 aHaram, Santosh, K.1 aMarkad, Ganesh1 aPuranik, Vedavati, G.1 aSalunke-Gawali, Sunita  uhttp://library.ncl.res.in/content/molecular-structures-and-biological-evaluation-2-chloro-3-n-alkylamino-14-napthoquinone-002214nas a2200277   4500008004100000022001400041245010800055210006900163260007300232300001000305490000900315520124800324653001301572653000801585653002101593653002301614653001401637653001501651100002101666700002401687700002201711700002301733700002601756700002701782856012701809       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<p>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.</p>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  uhttp://library.ncl.res.in/content/first-naphthosemiquinone-complex-k-vitamin-k3-analog-experiment-and-density-functional-0