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172 results on '"Harjani, Jitendra R."'

3. Development of 1,2,4-oxadiazole antimicrobial agents to treat enteric pathogens within the gastrointestinal tract

Author

Pitcher, Noel P., Harjani, Jitendra R., Zhao, Yichao, Jin, Jianwen, Knight, Daniel, Li, Lucy, Putsathit, Papanin, Riley, Thomas V., Carter, Glen P., Baell, Jonathan B., Pitcher, Noel P., Harjani, Jitendra R., Zhao, Yichao, Jin, Jianwen, Knight, Daniel, Li, Lucy, Putsathit, Papanin, Riley, Thomas V., Carter, Glen P., and Baell, Jonathan B.

Abstract

Colonization of the gastrointestinal (GI) tract with pathogenic bacteria is an important risk factor for the development of certain potentially severe and life-threatening healthcare-associated infections, yet efforts to develop effective decolonization agents have been largely unsuccessful thus far. Herein, we report modification of the 1,2,4-oxadiazole class of antimicrobial compounds with poorly permeable functional groups in order to target bacterial pathogens within the GI tract. We have identified that the quaternary ammonium functionality of analogue 26a results in complete impermeability in Caco-2 cell monolayers while retaining activity against GI pathogens Clostridioides difficile and multidrug-resistant (MDR) Enterococcus faecium. Low compound recovery levels after oral administration in rats were observed, which suggests that the analogues may be susceptible to degradation or metabolism within the gut, highlighting a key area for optimization in future efforts. This study demonstrates that modified analogues of the 1,2,4-oxadiazole class may be potential leads for further development of colon-targeted antimicrobial agents.

Published
2022

5. Discovery of Potent and Fast-Acting Antimalarial Bis-1,2,4-triazines

Author

Priebbenow, Daniel L., primary, Mathiew, Mitch, additional, Shi, Da-Hua, additional, Harjani, Jitendra R., additional, Beveridge, Julia G., additional, Chavchich, Marina, additional, Edstein, Michael D., additional, Duffy, Sandra, additional, Avery, Vicky M., additional, Jacobs, Robert T., additional, Brand, Stephen, additional, Shackleford, David M., additional, Wang, Wen, additional, Zhong, Longjin, additional, Lee, Given, additional, Tay, Erin, additional, Barker, Helena, additional, Crighton, Elly, additional, White, Karen L., additional, Charman, Susan A., additional, De Paoli, Amanda, additional, Creek, Darren J., additional, and Baell, Jonathan B., additional

Published
2021
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6. An ionic liquid mediated Friedel-Crafts addition of arenes to isothiocyanates

Author

Naik, Prashant U., Nara, Susheel J., Harjani, Jitendra R., and Salunkhe, Manikrao M.

Subjects
Solvents -- Composition, Catalysts -- Composition, Thiols, Amides, Ionic solutions, Chemical compounds -- Composition, Chemical research -- Analysis
Abstract

A new protocol is developed for the synthesis of N-substituted thioamides, employing arenes and isothiocyanates in 1-butyl-3-methylimidazolium chloroaluminate ionic liquid, [bmim]Cl*2Al[Cl.sup.3], as a homogenous Lewis acid catalyst and solvent. The effect of Lewis acidity and the stoichiometry of the ionic liquid on the extent of product formation is studied. Studies reveal that a progressive increase in yields was observed with increasing Lewis acidity, and two equivalents of [bmim]Cl*2Al[Cl.sup.3] was the optimal amount for the reaction. A distinct para selectivity for the incoming thioamido group on activated arenes was observed under ambient conditions. Key words: arenes, isothiocyanates, Friedel-Crafts, ionic liquids, thioamides.

Published
2003

7. Friedel-Crafts sulfonylation in 1-butyl-3-methylimidazolium chloroaluminate ionic liquids

Author

Nara, Susheel J., Harjani, Jitendra R., and Salunkhe, Manikrao M.

Subjects
Chemistry, Organic -- Research, Ionic solutions -- Physiological aspects, Chlorides -- Physiological aspects, Aluminum -- Physiological aspects, Acids -- Physiological aspects, Catalysts -- Physiological aspects, Benzene -- Physiological aspects, Biological sciences, Chemistry
Abstract

Research has been conducted on the Friedel-Crafts sulfonylation reaction of benzene and substituted benzenes with the 4-methyl benzenesulfonyl chloride. The use of the 1-butyl-3-methylimidazolium chloroaluminate ionic liquids as a reaction media and as Lewis acid catalyst for the Friedel-Crafts sulfonylation reaction is described and the details are reported.

Published
2001

11. 3,3′-Disubstituted 5,5′-Bi(1,2,4-triazine) Derivatives with Potent in Vitro and in Vivo Antimalarial Activity

Author

Xue, Lian, primary, Shi, Da-Hua, additional, Harjani, Jitendra R., additional, Huang, Fei, additional, Beveridge, Julia G., additional, Dingjan, Tamir, additional, Ban, Kung, additional, Diab, Sarah, additional, Duffy, Sandra, additional, Lucantoni, Leonardo, additional, Fletcher, Sabine, additional, Chiu, Francis C. K., additional, Blundell, Scott, additional, Ellis, Katherine, additional, Ralph, Stuart A., additional, Wirjanata, Grennady, additional, Teguh, Silvia, additional, Noviyanti, Rintis, additional, Chavchich, Marina, additional, Creek, Darren, additional, Price, Ric N., additional, Marfurt, Jutta, additional, Charman, Susan A., additional, Cuellar, Matthew E., additional, Strasser, Jessica M., additional, Dahlin, Jayme L., additional, Walters, Michael A., additional, Edstein, Michael D., additional, Avery, Vicky M., additional, and Baell, Jonathan B., additional

Published
2019
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12. Metal chelate formation using a task-specific ionic liquid

Author

Harjani, Jitendra R., Friscic, Tomislav, Macgillivray, Leonard R., and Singer, Robert D.

Subjects
Ionic solutions -- Chemical properties, Imidazole -- Chemical properties, Chelates -- Chemical properties, Chemistry
Abstract

The design, synthesis and X-ray crystal structural analysis of a metal chelate complex prepared from an imidazolium-based task-specific ionic liquid (TSIL) that contains an ethylaminediacetic acid (EDA) as a chelating moiety is described. The methodology could be extended to derive TSILs from tetraalkylammonium, pyridinium, pyrollidinium and phosphonium salts, since majority of ionic liquids are prepared via quarternization of N- or P-containing compounds,

Published
2006

14. 8-Mercaptoguanine Derivatives as Inhibitors of Dihydropteroate Synthase

Author

Dennis, Matthew L., primary, Lee, Michael D., additional, Harjani, Jitendra R., additional, Ahmed, Mohamed, additional, DeBono, Aaron J., additional, Pitcher, Noel P., additional, Wang, Zhong-Chang, additional, Chhabra, Sandeep, additional, Barlow, Nicholas, additional, Rahmani, Raphaël, additional, Cleary, Ben, additional, Dolezal, Olan, additional, Hattarki, Meghan, additional, Aurelio, Luigi, additional, Shonberg, Jeremy, additional, Graham, Bim, additional, Peat, Thomas S., additional, Baell, Jonathan B., additional, and Swarbrick, James D., additional

Published
2018
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17. Design, Synthesis, and Characterization of Cyclic Peptidomimetics of the Inducible Nitric Oxide Synthase Binding Epitope That Disrupt the Protein–Protein Interaction Involving SPRY Domain-Containing Suppressor of Cytokine Signaling Box Protein (SPSB) 2 and Inducible Nitric Oxide Synthase

Author

Harjani, Jitendra R., primary, Yap, Beow Keat, additional, Leung, Eleanor W. W., additional, Lucke, Andrew, additional, Nicholson, Sandra E., additional, Scanlon, Martin J., additional, Chalmers, David K., additional, Thompson, Philip E., additional, Norton, Raymond S., additional, and Baell, Jonathan B., additional

Published
2016
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19. Structural Basis for the Selective Binding of Inhibitors to 6-Hydroxymethyl-7,8-dihydropterin Pyrophosphokinase from Staphylococcus aureus and Escherichia coli

Author

Dennis, Matthew L., primary, Pitcher, Noel P., additional, Lee, Michael D., additional, DeBono, Aaron J., additional, Wang, Zhong-Chang, additional, Harjani, Jitendra R., additional, Rahmani, Raphaël, additional, Cleary, Ben, additional, Peat, Thomas S., additional, Baell, Jonathan B., additional, and Swarbrick, James D., additional

Published
2016
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26. Further investigation of the biodegradability of imidazolium ionic liquids

Author

Harjani, Jitendra R., Farrell, Jeff, García Ramón, María Teresa, Singer, Robert D., Scammells, Peter J., Harjani, Jitendra R., Farrell, Jeff, García Ramón, María Teresa, Singer, Robert D., and Scammells, Peter J.

Abstract

In continuation of our earlier investigations, this report presents a rationale behind the design of a series of imidazolium based ionic liquids and their biodegradation using the CO2 headspace test (ISO 14593 method, OECD 310). The effect on biodegradability of these salts through variation of the N-substituted side chains of imidazolium ions was examined further through incorporation of various functional groups and increased alkyl chain lengths. A series of anions containing moieties known to be biodegradable were also incorporated into a number of imidazolium based salts and examined in a similar fashion.

Published
2009

27. The design and synthesis of biodegradable pyridinium ionic liquids

Author

Harjani, Jitendra R., Singer, Robert D., García Ramón, María Teresa, Scammells, Peter J., Harjani, Jitendra R., Singer, Robert D., García Ramón, María Teresa, and Scammells, Peter J.

Abstract

Ionic liquids with a pyridinium cation bearing an ester side chain moiety were prepared from either pyridine or nicotinic acid and their biodegradability was evaluated using the CO2 Headspace test (ISO 14593). ILs of this type showed exceptionally high levels of biodegradation under aerobic conditions and can be classified as ‘readily biodegradable’.

Published
2008

29. Contrasting Reactivity of CS2 with Cyclic vs. Acyclic Amidines.

Author

Ang, M. Trisha C., Phan, Lam, Alshamrani, Aliyah K., Harjani, Jitendra R., Wang, Ruiyao, Schatte, Gabriele, Mosey, Nicholas J., and Jessop, Philip G.

Subjects
CARBON-hydrogen bonds, AMIDINES, ISOTHIOCYANATES, SULFUR, CARBON disulfide
Abstract

The interaction between carbon dioxide (CO2) and amidines such as 1,8-diazabicyclo[5.4.0]undecane (DBU) has been extensively studied, but the reaction of isovalent CS2 with such bases has been largely ignored, apart from a single crystallography report. Acyclic acetamidines are cleaved by CS2 at room temperature to give an isothiocyanate and a thioacetamide. Because the pathway to that cleavage involves a rotation that is difficult for cyclic amidines, the reaction of CS2 with cyclic amidines produces an entirely different product: a cyclic carbamic carboxylic trithioanhydride structure. The path to that product involves sp3 C-H activation leading to the formation of a new C-C bond at a carbon α to the central carbon of the amidine group. Alkylation and ring-opening of the cyclic carbamic carboxylic trithioanhydride has also been demonstrated under ambient conditions. [ABSTRACT FROM AUTHOR]

Published
2015
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48. 19F NMR as a Probe of Ligand Interactions with the iNOS Binding site of SPRY Domain-Containing SOCS Box Protein 2.

Author

Leung, Eleanor W. W., Yagi, Hiromasa, Harjani, Jitendra R., Mulcair, Mark D., Scanlon, Martin J., Baell, Jonathan B., and Norton, Raymond S.

Subjects
NITRIC-oxide synthases, LIGAND binding (Biochemistry), NUCLEAR magnetic resonance, FLUORINE, BINDING sites, ANTI-infective agents, SURFACE plasmon resonance
Abstract

SPRY domain-containing SOCS box protein 2 (SPSB2) regulates inducible nitric oxide synthase ( iNOS) by targeting it for proteasomal degradation. Inhibiting this interaction prolongs the intracellular lifetime of iNOS, leading in turn to enhanced killing of infectious pathogens such as bacteria and parasites. SPSB2 recognizes a linear motif (DINNN) in the disordered N-terminus of iNOS, and ligands that target the DINNN binding site on SPSB2 are potentially novel anti-infective agents. We have explored 19F NMR as a means of probing ligand binding to SPSB2. All six Trp residues in SPSB2 were replaced with 5-fluorotryptophan (5-F-Trp) by utilizing a Trp auxotroph strain of Escherichia coli. The labeled protein was well folded and bound a DINNN-containing peptide with similar affinity to native SPSB2. Six well-resolved 5-F-Trp resonances were observed in the 19F NMR spectrum and were assigned using site-directed mutagenesis. The 19F resonance of W207 was significantly perturbed upon binding to DINNN-containing peptides. Other resonances were perturbed to a lesser extent although in a way that was sensitive to the composition of the peptide. Analogues of compounds identified in a fragment screen also perturbed the W207 resonance, confirming their binding to the iNOS peptide-binding site on SPSB2. 19F NMR promises to be a valuable approach in developing inhibitors that bind to the DINNN binding site. [ABSTRACT FROM AUTHOR]

Published
2014
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