- 2-Aryl benzazole derived new class of anti-tubercular compounds: Endowed to eradicate mycobacterium tuberculosis in replicating and non-replicating forms
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The high mortality rate and the increasing prevalence of Mtb resistance are the major concerns for the Tuberculosis (TB) treatment in this century. To counteract the prevalence of Mtb resistance, we have synthesized 2-aryl benzazole based dual targeted molecules. Compound 9m and 9n were found to be equally active against replicating and non-replicating form of Mtb (MIC(MABA) 1.98 and 1.66 μg/ml; MIC(LORA) 2.06 and 1.59 μg/ml respectively). They arrested the cell division (replicating Mtb) by inhibiting the GTPase activity of FtsZ with IC50 values 45 and 64 μM respectively. They were also capable of kill Mtb in non-replicating form by inhibiting the biosynthesis of menaquinone which was substantiated by the MenG inhibition (IC50 = 11.62 and 7.49 μM respectively) followed by the Vit-K2 rescue study and ATP production assay.
- Datta, Dhrubajyoti,Debnath, Joy,Franzblau, Scott G.,Ghosh, Kalyan Sundar,Hari, Natarajan,Ma, Rui,Rana, Shiwani,Velappan, Anand Babu
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- Synthesis and mesomorphic investigations of liquid crystalline compounds having a benzothiazole ring
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Two homologous series of calamitic liquid crystals containing a benzothiazole ring and two different linkages have been prepared, and their liquid crystalline properties are studied and compared with each other and those of similar structure. The mesogens with only the cinnamate linking group showed better thermal properties than those with an ester. Nematic and smectic phases were observed. All the compounds of both the series were characterized by elemental analysis, FT-IR, mass spectrometry, 1H-NMR, and 13C-NMR. Phase transition temperatures and the thermal parameters were obtained from differential scanning calorimetery (DSC). The textural observations were performed using hot-stage Polarizing Optical Microscopy (POM).
- Thaker,Chothani,Patel,Dhimmar,Solanki,Patel, Neeraj,Patel,Makawana
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- Synthesis, characterization and mesomorphic properties of new rod-like thiophene based liquid crystals
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Two new mesogenic homologous series of Schiff base esters, 2-[4-(4-n-Alkoxy benzoyloxy) benzylidenamino] 3-cyno thiophine (Series-A) and Schiff base cinnamates, 2-[4-(4-n-alkoxy cinnamoyloxy) benzylidenamino] 3-cyano thiophene (Series-B), comprising a thiophene moiety were synthesized. Structural elucidation was carried out using elemental analysis and spectroscopic techniques such as FT-IR, 1H-NMR and 13C-NMR, and mass spectrometry. The mesomorphic properties and thermal stabilities of the title compounds were studied by using differential scanning calorimetry and optical polarizing microscopy. All the derivatives are mesomorphic in nature showing the nematic phase, and the higher members of Series-A show a smectic C phase whereas Series-B exhibits only the nematic mesophase. The mesomorphic properties of the present series are compared with other structurally related compounds. Taylor and Francis Group, LLC.
- Thaker,Patel,Dhimmar,Solnki,Chothani,Patel,Patel,Makavana
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experimental part
p. 98 - 113
(2012/10/07)
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- Synthesis and characterization of liquid crystalline materials incorporating the novel 4-amino-1,2,4-triazole and isonicotinic acid hydrazide moiety
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We report the synthesis and evaluation of thermal behavior of two new mesogenic homologous series of liquid crystalline compound containg 1,2,4-triazole and isonicotinic acid ring at the terminus of the molecule viz. 4-[(4H-1,2,4-triazol-4-ylimino) methyl] phenyl 4-alkoxybenzoate and 4-(2-isonicotinoylcarbonohydrazonoyl) phenyl 4-alkoxybenzoate. Both series have been characterized by elemental analysis, FT-IR, mass spectrometry, 1H-NMR, and 13C-NMR. Phase transition temperatures and the thermal parameters were obtained from differential scanning calorimetry (DSC). The texture observation was performed under polarizing optical microscopy (PMO) attached with Mettler hot stage. All the derivatives are mesomorphic in nature showing nematic phase and the higher member of both series shows smectic phase. The use of isonicotinic acid and triazole as a terminal group has a very dramatic effect on the melting and clearing points. The mesomorphic behavior has been analyzed in terms of structural property relationship.
- Thaker,Patel, Pranay
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- Synthesis and mesomorphic properties of fluorinated Schiff's base esters containing alkyl and alkoxy end groups
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Two series of fluorinated Schiff's base esters have been synthesized and characterized. Their chemical structures were identified by FTIR, 1H NMR, and elemental analysis (EA). Their mesomorphic properties were studied by polarizing optical, microscopy (PO
- Wei, Qiang,Yang, Huai,Wang, Yanbin
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experimental part
p. 31 - 38
(2010/03/03)
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- Synthesis, characterization, and mesomorphic properties of new liquid-crystalline compounds involving ester-azomethine central linkages, lateral substitution, and a thiazole ring
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In continuation with our work on liquid crystals with unconventional molecular structures, two homologous series that have 1,4-disubstitution and 1,3,4-trisubstitution in the central phenyl ring, such as 2[(4-n-alkoxy- benzyloxy) phenyl azomethine]-5-methyl thiazole and 2-[(4-n-alkoxy-benzyloxy)-2- hydroxy salicyladimine]-5-methyl thiazole, have been synthesized. They have been characterized by elemental analysis, FT-IR, 1HNMR, 13CNMR, and mass spectrometry. The liquid-crystalline behavior of these compounds was observed by differential scanning calorimetry (DSC) and polarizing microscopy. All the compounds of the 1,4-disubstituted series show an enantiotropic nematic phase only, whereas the compounds of the 1,3,4-trisubstituted series show smectic and nematic phases. Some mesogens with a lateral hydroxy group were also synthesized to evaluate the effect of this group on melting point, transition temperatures, and mesophase morphology.
- Thaker,Patel, Pranay,Vansadia,Patel
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- Synthesis and mesomorphic characterisation of chiral homologues
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Chiral liquid crystals have attracted considerable interest as they exhibit a good variety of modulated phases. We have synthesised a homologous series viz., 4-(4!-n-alkoxy benzoyloxy) benzylidene-4!!-1-(s)-methyl propoxy anilines, incorporating a terminal chiral centre, inorder to obtain better understanding of the relationship between molecular structure and appearance of SmC*phase in the molecules. It is observed that, in the present series the lower members upto butyl are pure nematogens, while pentyl to hexadecyl derivatives exhibit classical smectic as well as nematic mesophases. An additional smectic C* phase is observed in the middle octyl to dodecyl homologues. The homologues have been characterised by IR, NMR and DSC. Their mesomorphic properties have been compared with structurally related homologous series.
- Dave, Jayrang S.,Menon, Meera R.,Patel, Pratik R.
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p. 575 - 587
(2007/10/03)
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- Synthesis of new mesogenic homologous series with broken alkoxy chain
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A new mesogenic homologous series with broken alkoxy chain at the terminus of long polarizable molecules having following general formula have been synthesized. RO-C6H4-COO-C6H4-CH=N-C 6H4-COOCH2CH2OCH2CH 3 Where, R=-CnH2n+1; n=1 to 8, 10, 12, 14 and 16. All the members exhibit enantiotropic mesomorphism. Methoxy derivative is purely nematogenic. Ethoxy to n-hexyloxy derivatives exhibit enantiotropic smectic-A as well as nematic mesophases. n-Heptyloxy to n-hexadecyloxy derivatives exhibit only enantiotropic smectic A mesophases. The thermal stabilities and the commencement of smectic phase of the present series are compared with those of other structurally related series.
- Prajapati,Sharma,Chudgar
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p. 815 - 823
(2007/10/03)
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- Mesomorphic Behavior of N,N'-Bis-3,3'-diaminodiphenylsulfones
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A new series of sulfur ligated siamese twin mesogens, N,N'-bis-3,3'diaminodiphenylsulfones has been studied for the thermotropic phase transition behavior.A stable or metastable nematic phase is exhibited by the methoxy
- Matsunaga, Y.,Yuri, T.
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p. 145 - 150
(2007/10/02)
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- Liquid-Crystalline Heterocycloalkanes. III. Synthesis and Liquid-Crystalline Properties of Substituted 1,3-Dioxadecalines
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Liquid-crystalline 2-substituted and 2,6-disubstituted 1,3-dioxadecalines (4-6) were synthesized by acid-catalyzed acetalization of trans-2-hydroxymethylcyclohexanol (1) or trans-4-alkyl-trans-2-hydroxymethylcyclohexanoles (2) with aldehydes 3 whereby the desired trans-isomers were formed only.The syntheses of the various aldehydes are also described.Special attention is drawn on the evolution of mesogenic properties of the title compounds 4-6 in comparison with known decalines and 1,3-dioxanes.It was found that the clearing temperatures of the synthesized 1,3-dioxadecalines are always lower than those of the corresponding decaline derivatives, due to the deformation of the decaline-ringsystem by the introduction of two oxygen-atoms.The comparison of 1,3-dioxanes and 1,3-dioxadecalines shows that the dioxadecaline ringsystem tends to suppress smectic mesophases in favour of nematics.A first example of a liquid crystalline cis-fused 1,3-dioxadecaline (8) is described, too.
- Tschierske, C.,Zaschke, H.
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- New Liquid Crystalline Homologous Series Exhibiting the Smectic C Phase
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A liquid cristalline homologous series of N--4-butylanilides and their hydroxyl derivatives at the 2-position were synthesized, and then the liquid-crystalline-phase transitions were determined using a differential scanning calorimeter and a polarizing microscope.All of the members exhibit a nematic phase, and a smectic C phase can be observed for the homologoues with a relatively long alkoxy chain.
- Sakagami, Sakumitshu
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p. 1153 - 1154
(2007/10/02)
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- The Preparation and Thermal Properties of Terminal Disubstituted N-(4-Benzoyloxybenzylidene)anilines
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The homologous series of N--4-(2-methylbutoxy)aniline (1), and N-benzylidene>-4-n-alkoxyaniline (2), and N--4-(2-methylbutoxy)aniline (3) where the 2-methylbutoxyl group has an S-configuration, have been prepared.Series 1 and 2 form a chiral smectic C (S*C) phase in addition to a cholesteric (Ch) and a chiral smectic G (S*G) phases, and series 3 form (S*C) and Ch phases.
- Takenaka, Shunsuke,Ikemoto, Tetsuya,Kusabayashi, Shigekazu
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p. 3965 - 3966
(2007/10/02)
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