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51.
Bharathi Avula Babu L. Tekwani Narayan D. Chaurasiya NP Dhammika Nanayakkara Yan‐Hong Wang Shabana I. Khan Vijender R. Adelli Rajnish Sahu Mahmoud A. Elsohly James D. McChesney Ikhlas A. Khan Larry A. Walker 《Journal of mass spectrometry : JMS》2013,48(2):276-285
Therapeutic efficiency and hemolytic toxicity of primaquine (PQ), the only drug available for radical cure of relapsing vivax malaria are believed to be mediated by its metabolites. However, identification of these metabolites has remained a major challenge apparently due to low quantities and their reactive nature. Drug candidates labeled with stable isotopes afford convenient tools for tracking drug‐derived metabolites in complex matrices by liquid chromatography‐tandem mass spectrometry (LC‐MS‐MS) and filtering for masses with twin peaks attributable to the label. This study was undertaken to identify metabolites of PQ from an in vitro incubation of a 1:1 w/w mixture of 13C6‐PQ/PQ with primary human hepatocytes. Acquity ultra‐performance LC (UHPLC) was integrated with QTOF‐MS to combine the efficiency of separation with high sensitivity, selectivity of detection and accurate mass determination. UHPLC retention time, twin mass peaks with difference of 6 (originating from 13C6‐PQ/PQ), and MS‐MS fragmentation pattern were used for phenotyping. Besides carboxy‐PQ (cPQ), formed by oxidative deamination of PQ to an aldehyde and subsequent oxidation, several other metabolites were identified: including PQ alcohol, predictably generated by oxidative deamination of PQ to an aldehyde and subsequent reduction, its acetate and the alcohol's glucuronide conjugate. Trace amounts of quinone‐imine metabolites of PQ and cPQ were also detected which may be generated by hydroxylation of the PQ/cPQ quinoline ring at the 5‐position and subsequent oxidation. These findings shed additional light on the human hepatic metabolism of PQ, and the method can be applied for identification of reactive PQ metabolites generated in vivo in preclinical and clinical studies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
52.
Afshan Banu D.E. Vasundhara Ravi S. Lamani I.A.M. Khazi Noor Shahina Begum 《Journal of Saudi Chemical Society》2013,17(2):211-217
The preparation of 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)-5-morpholin-1-ylmethyl imidazo[2,1-b][1,3,4]thiadiazole via the intermediate 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)Imidazo[2,1-b][1,3,4] thiadiazole is described. Elemental analysis, IR spectrum, 1H NMR and X-ray crystal structure analyses were carried out to determine the compositions and molecular structures of the two compounds. The crystal packing exhibits intermolecular C–H?O, C–H?N, C–H?F and π–π stacking interactions leading to the formation of the supramolecular network. 相似文献
53.
Molecular orbital calculations at the DFT-B3LYP/aug-cc-pVDZ level were performed for the possible tautomers of 1-amino-3-nitro-1,2,4-triazol-5-one-2-oxide. We have examined the substitution effects of amino and nitro groups by comparing calculated geometries, relative energies, and electrostatic potentials of model molecules. The optimized structures, vibrational frequencies, and thermodynamic values for triazol-5-one-N-oxides were obtained in their ground state. The results show 1H, 4H tautomers to be most stable. Detonation velocity and detonation pressure were evaluated by the Kamlet and Jacob equations based on the predicted density and the calculated heat of explosion. Explosive properties appear to be promising compared with those of 1,3,5-trinitro-1,3,5-triazine (D = 8.75 km/s, P = 34.7 Gpa) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (D = 8.96 km/s, P = 35.96 Gpa), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (D = 9.20 km/s, P = 42.0 Gpa) and octanitrocubane (D = 9.90 km/s, P = 48.45 GPa). The designed triazol-5-one-N-oxides satisfy the criteria of high energy density materials. 相似文献
54.
Ranjith?Munigunti Symon?Gathiaka Orlando?Acevedo Rajnish?Sahu Babu?Tekwani Angela?I?CalderónEmail author 《Chemistry Central journal》2013,7(1):175
Background
The compounds 1,4-napthoquinone (1,4-NQ), bis-(2,4-dinitrophenyl)sulfide (2,4-DNPS), 4-nitrobenzothiadiazole (4-NBT), 3-dimethylaminopropiophenone (3-DAP) and menadione (MD) were tested for antimalarial activity against both chloroquine (CQ)-sensitive (D6) and chloroquine (CQ)-resistant (W2) strains of Plasmodium falciparum through an in vitro assay and also for analysis of non-covalent interactions with P. falciparum thioredoxin reductase (PfTrxR) through in silico docking studies.Results
The inhibitors of PfTrxR namely, 1,4-NQ, 4-NBT and MD displayed significant antimalarial activity with IC50 values of?<?20 μM and toxicity against 3T3 cell line. 2,4-DNPS was only moderately active. In silico docking analysis of these compounds with PfTrxR revealed that 2,4-DNPS, 4-NBT and MD interact non-covalently with the intersubunit region of the enzyme.Conclusions
In this study, tools for the identification of PfTrxR inhibitors using phenotyphic screening and docking studies have been validated for their potential use for antimalarial drug discovery project.55.
One-pot three component synthesis of novel pyrido[1,4]-oxazepine fused spiropyrrolidines has been accomplished in good yields by 1,3-dipolar cycloaddition reaction of azomethine ylide, derived from paraformaldehyde and sarcosine with (E)-4-benzylidene-hexahydro-1H-pyrido[2,1-c][1,4]-oxazepine-3(7H)-one as dipolarophiles derived from Baylis-Hillman adducts. The effect of solvent on the [3 + 2]-cycloaddition reaction is also studied. 相似文献
56.
S. Balasubramonian Ravi Kant Srivastav Shekhar Kumar D. Sivakumar Pranay Kumar Sinha M. Sampath U. Kamachi Mudali 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(3):1703-1707
Several solutions of 30 % TBP/n-dodecane were equilibrated with different concentrations of aqueous nitric acid solutions at 298.15 K at a phase ratio of unity. The resultant equilibrated aqueous and organic solutions were analyzed for acidity. A three-solvate model with molecular HNO3 based mechanism was assumed for nitric acid extraction by TBP. With nonlinear chemometric methods, the coefficients were evaluated. With the set of optimized coefficients, derived on the basis of experiments reported in this work, the estimated solvate species and free-TBP species in the TBP containing organic phase were found to be in good agreement with the reported concentrations in the literature. 相似文献
57.
The first stereoselective total synthesis of natural product, dendrodolide A (1) is described from readily available (R)-propylene oxide and 3-buten-1-ol as starting materials. The synthesis was achieved in 10 steps with an overall yield of 19.1%. The key steps involved in the synthesis are Jacobsen hydrolytic kinetic resolution, epoxide ring opening with 2-allyl-1, 3-dithiane, Yamaguchi esterification, and ring-closing metathesis (RCM). 相似文献
58.
Satyanarayana Reddy Jaggavarapu Anand Solomon Kamalakaran Jagadeesh Babu Nanubolu Venkata Prasad Jalli Sravan Kumar Gangisetty Gopikrishna Gaddamanugu 《Tetrahedron letters》2014
Efficient and facile synthesis of 7H-benzopyrano[3,2-c]coumarins has been achieved by mild base promoted reaction of 4-chloro-3-formylcoumarin with diversely functionalized resorcinols. All the products were obtained as pure precipitates from the reaction mixture and the structure of the product was confirmed by X-ray analysis. 相似文献
59.
A simple, green, and efficient protocol is reported for the preparation of aryl-7,8-dihydro[1,2,4]triazolo[4,3-a]-pyrimidine-6-carbonitriles through one-pot multi component reaction using substituted aromatic aldehydes, malononitrile, and 3-amino[1,2,4]triazole. The reaction is catalyzed by boric acid in aqueous micellar condition. Present protocol incorporates environmentally non-hazardous reaction condition, easy work-up, and use of recyclable catalytic system with associated benefits like excellent yield (84–96%) and shorter reaction time (20 min). Proposed methodology offers rapid access to substituted aryl-7,8-dihydro[1,2,4]triazolo[4,3-a]pyrimidine-6-carbonitriles with high atom-economy and catalytic efficiency. 相似文献
60.
Triflic acid-mediated stereoselective direct lactonization of a variety of α-amino γ,δ-unsaturated carboxylic acid esters and the construction of new γ-butyrolactone structural motifs are reported. Several α-amino γ,δ-unsaturated carboxylic acid esters underwent stereo- and regioselective 1,5-cyclization and afforded a variety of highly substituted homoserine lactone scaffolds having contiguous stereocenters. The direct lactonization of the chiral α-amino γ,δ-unsaturated carboxylic acid esters with triflic acid led to the enantioselective synthesis of the novel homoserine lactones. A plausible mechanism for the direct lactonization of α-amino γ,δ-unsaturated carboxylic acid esters is presented. The stereochemistry of major isomers 3f, 7a, 7b, and 7d was unambiguously established from the X-ray structure analysis. 相似文献