02832nas a2200289   4500008004100000022001400041245013800055210006900193260007300262300001000335490000900345520178500354653002402139653002402163653000902187653002302196653001902219100001702238700002102255700002102276700002102297700002302318700001902341700002602360700002702386856012902413       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  uhttps://library.ncl.res.in/content/molecular-structures-and-biological-evaluation-2-chloro-3-n-alkylamino-14-napthoquinone-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<p>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.</p>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-0