- Some contribution to W(VI)-peroxo-chemistry: Synthesis, spectroscopic characterization, reactivity and DFT studies
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Synthesis of white microcrystalline oxodiperoxotungstate(VI) complexes, K[WO(O2)2(L)(H2O)]·H2O, (L ?= ?salicylate, 5-chlorosalicylate, 4-hydroxybenzoate) have been achieved from reaction of Na2WO4·2H2O with 30% H2O2 and the respective hetero-ligands at pH Ca. 7–7.5 in aqueous medium. The newly synthesized compounds were comprehensively characterized by elemental analyses, spectral studies, room temperature magnetic moment measurements and mass spectrometric studies. Infrared spectra suggest that, peroxo groups are bonded to the WO+4 center in a triangular bidentate (C2v) fashion and the hetero-ligands benzene-core hydroxycarboxylic acids viz. salicylic acid, 5-chlorosalicylic acid, 4-hydroxybenzoic acid in anoinic form are coordinated in monodentate manner. Compounds are fairly stable in aqueous solution for sufficient period of time. The results of mass spectrometric analysis lend support to the molecular composition of the complexes ascertained on the basis of elemental analyses and spectroscopic studies. Compound potassium(aquo)(5-chlorosalicylato)oxodiperoxotungstate(VI)monohydrate, K[WO(O2)2(5-chlorosalicylate)(H2O)]·H2O, act as an oxidant of bromide ion in aqueous phase bromination of chosen organic substrates to their corresponding bromo organics. Density Functional Theory (TD-DFT) calculations were performed on the synthesized complexes substantiated the experimentally obtained results. The TD-DFT optimized structures are in excellent agreement with the results of elemental analyses, spectral as well as mass spectrometric data.
- Bhattacharjee, M.,Boruah, S. R.,Chowdhury, S.,Das, N.,Dutta Purkayastha, R. N.
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- Synthesis, anti-HIV-1 and antiproliferative evaluation of novel 4-nitroimidazole derivatives combined with 5-hydroxy-4-pyridinone moiety
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In an effort to synthesize more effective non-nucleoside reverse transcriptase inhibitors (NNRTIs) against the HIV-1 infection, a new series of novel 4-nitroimidazole derivatives combined with 5-hydroxy-4-pyridinone moiety were designed by molecular docking studies, prepared and characterized by spectroscopic techniques. All the synthesized compounds were in vitro evaluated for their inhibitory effect against the HIV-1 replication in the MT-4 cells. Results showed that none of these synthesized compounds displayed any specific anti HIV-1 activity. Surprisingly, these compounds showed high cytotoxicity against MT-4 cells with low selectivity index (50 = 1.3 μM and EC50 = 1.8 μM respectively).
- Shirvani, Pouria,Fassihi, Afshin,Saghaie, Lotfollah,Van Belle, Siska,Debyser, Zeger,Christ, Frauke
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- Green synthesis of bromo organic molecules and investigations on their antibacterial properties: An experimental and computational approach
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A simple, environmentally benign methodology has been developed to synthesize some bromoorganic compounds which have potential as antimicrobial agents. The required compounds were obtained through microwave (MW) irradiation, on-water reactions and using cetyltrimethylammonium tribromide (CTMATB) as the bromine source. The high yield of the product could be achieved within short reaction times, thus representing the main attribute of the present synthetic approach. The compounds were evaluated for in vitro antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Bacillus subtilis. Further, in silico studies were carried out to elucidate the interactions of the compounds with the bacterial proteins.
- Longkumer, Naruti,Richa, Kikoleho,Karmaker, Rituparna,Kuotsu, Visekhonuo,Supong, Aola,Jamir, Latonglila,Bharali, Pranjal,Sinha, Upasana Bora
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p. 276 - 283
(2019/07/12)
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- Syntheses, Structural Characterization, Reactivity, and Theoretical Studies on Some Heteroligand Oxoperoxotungstate(VI)
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White microcrystalline diamagnetic oxoperoxotungstate(VI) complexes K[WO(O2)2F]·H2O, K2[WO(O2)2(CO3)]·H2O, [WO(O2)(SO4)(H2O)2] have been synthesized from reaction of Na2WO4·2H2O with aqueous HF, solid KHCO3, aqueous H2SO4 (W:F? 1:3; W: CO3 2 ? 1:1; and W: SO4 2 ? 1:3), and an excess of 30% H2O2 at pH 7.5–8. Precipitation was completed by the addition of precooled acetone. The occurrence of terminal W?O and triangular bidentate O2 2 ?(C 2 v) in the synthesized compounds was ascertained from IR spectra. The IR spectra also suggested that the F? and SO4 2 ? ions in K[WO(O2)2F]·H2O and [WO(O2)(SO4)(H2O)2] were bonded to the WO +4 center in monodentate manner, while CO3 2 ? ion in K2[WO(O2)2(CO3)]·H2O binds the metal center in bidentate chelating fashion. The complex [WO(O2)(SO4)(H2O)2] is stable upto 110°C. The water molecule in [WO(O2)(SO4)(H2O)2] is coordinated to the WO +4 center, whereas it occurs as water of crystallization in the corresponding peroxo(fluoro) and peroxo(carbonato) compounds. Mass spectra of the compounds are in good agreement with the molecular formulae of the complexes. K2[WO(O2)2(CO3)]·H2O acts as an oxidant for bromide in the aqueous-phase bromination of organic substrates to the corresponding bromo-organics, and the complex also oxidizes Hantzsch-1,4-dihydropyridine to the corresponding pyridine derivative in excellent yield at room temperature. Density functional theory computation was carried out to compute the frequencies of relevant vibrational modes and electronic properties, and the results are in agreement with the experimentally obtained data.
- Das, Nandita,Chowdhury, Shubhamoy,Dutta Purkayastha, Ranendra N.
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- A deuterated of the IDO inhibitor and its preparation and use (by machine translation)
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The invention provides a deuterated of the IDO inhibitor and its preparation and use, as shown in formula I provide compound or its crystalline form, a pharmaceutically acceptable salt, hydrate or solvate. The preparation of the compound or its crystalline form, a pharmaceutically acceptable salt, hydrate or solvate, can be regarded as the IDO inhibitor, can be used for the treatment of IDO related diseases, in particular cancer, viral infection, depression, neurodegenerative disease, trauma, age-related cataract, organ transplant rejection and autoimmune diseases. (by machine translation)
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Paragraph 0044; 0049; 0050; 0051
(2017/04/22)
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- Highly regioselective C-5 alkynylation of imidazoles by one-pot sequential bromination and Sonogashira cross coupling
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A variety of 2-substituted 5-alkynyl-1H-imidazoles were easily prepared by a one-pot sequential procedure involving a highly regioselective electrophilic C-5 bromination of 1,2-dimethyl-1H-imidazole, 2-chloro-1-methyl-1H-imidazole, and 2-aryl-1-methyl-1H-imidazoles, followed by an efficient palladium/copper co-catalyzed Sonogashira-type alkynylation.
- Bellina, Fabio,Lessi, Marco,Marianetti, Giulia,Panattoni, Alessandro
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supporting information
p. 3855 - 3857
(2015/06/08)
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- Hexamethonium bis(tribromide) (HMBTB) a recyclable and high bromine containing reagent
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A recyclable and high bromine containing di-(tribromide) reagent, hexamethonium bis(tribromide) (HMBTB) has been synthesized and utilized for the bromination of various organic substrates. The spent reagent hexamethonium bromide (HMB) can be effectively recycled by regenerating and reusing it without significant loss of activity. The crystalline and stable bis(tribromide) is an effective storehouse of very high percentage of active bromine requiring just half an equivalent of it for complete bromination. Both the Br3- moieties in HMBTB are nearly linear with Br-Br-Br angle of 179.55°.
- Paul, Bappi,Bhuyan, Bishal,Purkayastha, Debraj D.,Dhar, Siddhartha S.,Patel, Bhisma K.
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p. 5646 - 5650
(2015/09/21)
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- Fast halogenation of some N-heterocycles by means of N,N'-dihalo-5,5- dimethylhydantoin
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An instantaneous, selective and high-yielding halogenation process is reported. The method operates with imidazoles, pyrazoles, and indoles under benign reaction conditions. The developed process involves the use of N,N'-dihalo-5,5-dimethylhydantoins (halo=chlorine, bromine, iodine) as halogenation reagents that are activated by catalytic quantities of a strong Bronsted acid. Moreover, the halogenation process is switchable to produce either the mono- or di-halogenated products. Issues related to the reaction mechanism are investigated and a proposal for a reaction mechanism is disclosed.
- Sandtorv, Alexander H.,Bjorsvik, Hans-Rene
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p. 499 - 507
(2013/05/08)
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- HETEROARYL COMPOUNDS AND METHODS OF USE THEREOF
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Provided herein are heteroaryl compounds, methods of their synthesis, pharmaceutical compositions comprising the compounds, and methods of their use. In one embodiment, the compounds provided herein are useful for the treatment, prevention, and/or management of various disorders, such as CNS disorders and metabolic disorders, including, but not limited to, e.g., neurological disorders, psychosis, schizophrenia, obesity, and diabetes
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Page/Page column 103
(2011/12/14)
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- Regioselective, photochemical bromination of aromatic compounds using N-bromosuccinimide
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Regioselective nuclear bromination of aromatic compounds is investigated with N-bromosuccinimide as the brominating agent under UV irradiation to afford the corresponding brominated compounds. The reaction proceeds at ambient temperature (30 ± 2 °C) without any catalyst. In most of the reactions, regioselectively mono-brominated products are obtained in good to high yields. The conversion and selectivity for bromination depend on the nature of the substituent on the aromatic ring.
- Chhattise, Prakash K.,Ramaswamy,Waghmode, Suresh B.
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p. 189 - 194
(2008/03/30)
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- Green synthesis of tetraalkylammonium tribromide using cerium(IV) ammonium nitrate (CAN) as oxidant
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Cerium(IV) ammonium nitrate (CAN) mediates oxidation of tetraalkylammonium bromide to tetraalkylammonium tribromide in greener reaction conditions using water as solvent. The procedure is simple, convenient, and environmentally benign for the synthesis of tetraalkylammonium tribromide with great yields. Copyright Taylor & Francis Group, LLC.
- Borah, Ruli,Thakur, Ashim Jyoti
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p. 933 - 939
(2007/10/03)
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- Convenient multi-gram scale synthesis of polybrominated imidazoles building blocks
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The multi-gram scale polybromination of variously substituted imidazoles has been realized using a stoichiometric amount of the Br2-DMF complex. Good yields have been obtained compared to other methods using large amounts of acetic acid-sodium acetate buffer.
- Bahnous, Mebarek,Mouats, Chabane,Fort, Yves,Gros, Philippe C.
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p. 1949 - 1951
(2007/10/03)
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- Synthesis of didemnolines A-D, N9-substituted β-carboline alkaloids from the marine ascidian Didemnum sp.
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Didemnolines A-D (1-4) were synthesized and their structures were confirmed through comparisons of data for the synthetic material with those obtained for natural 1-4. The synthesis of didemnolines A (1) and C (3) involved the coupling of 1-[(benzyloxy)methyl]-4-chloromethyl-5- (thiomethyl)imidazole (6) with 7-bromo-β-carboline (5), while didemnolines B (2) and D (4) were formed through the analogous coupling of 6 with norharmon (7). Intermediate 6 was efficiently prepared from 1-[(benzyloxy)methyl]- 2,4,5-tribromoimidazole using a sequential one-pot halogen-metal exchange reaction and 7-Br-β-carboline was synthesized using a new approach.
- Schumacher, Robert W.,Davidson, Bradley S.
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p. 935 - 942
(2007/10/03)
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- An environmentally benign synthesis of organic ammonium tribromides (OATB) and bromination of selected organic substrates by tetrabutylammonium tribromide (TBATB)
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Stable crystalline organic ammonium tribromides (OATB), like Me4NBr3, Et4NBr3, Bu4NBr3, cetyltrimethylammonium tribromide, PyHBr3, can be readily synthesised from the reaction of the corresponding bromides with V2O5 and aqueous H2O2. Typically, TBATB, Bu4NBr3, brominates a variety of organic substrates rather easily under mild conditions. An activated aromatic ring is selectively brominated in the presence of an olefinic double bond.
- Chaudhuri, Mihir K.,Khan, Abu T.,Patel, Bhisma K.,Dey, Deepa,Kharmawophlang, Wancydora,Lakshmiprabha,Mandal, Gagan C.
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p. 8163 - 8166
(2007/10/03)
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- Use of the vinyl group as an efficient protecting group for azole N- atoms: Synthesis of polyfunctionalized imidazoles and thieno[2,3-d] ? [3,2-d]imidazole
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2,4,5-Tribromo-1-vinylimidazole was prepared from 2,4,5-tribromoimidazole and 1,2-dibromoethane and its Br-atoms were replaced regioselectively in the order 2 → 5 → 4 via Br → MgBr and other exchange reactions. Efficient removal of die vinyl groups from die resulting polyfunctionalized imidazoles was achieved with ozone or potassium permanganate. An extension of this methodology has allowed the first synthesis of thieno[2,3-d] ? [3,2-d]-imidazole.
- Hartley, David J.,Iddon, Brian
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p. 4647 - 4650
(2007/10/03)
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- Synthesis and Reactions of Brominated 2-Nitroimidazoles
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Various approaches to the synthesis of the hitherto-unknown 4(5)-bromo-2-nitroimidazole (5) are reported.Direct bromination of 2-nitroimidazole with N-bromosuccinimide gave the unreported 4,5-dibromo-2-nitroimidazole (10) in quantitative yield, but this could be selectively debrominated to give compound (5).While 1-methyl-2-nitroimidazole readily gave 4-bromo-1-methyl-2-nitroimidazole (15) on bromination, this could not be demethylated to give (5), and bromination of various other N-protected 2-nitroimidazoles was also unsuccessful.Lithiation of 4-bromo-1-tritylimidazole (21) followed by quenching with propyl nitrate gave (after detritylation and methylation) a mixture of a dimer (28) and compound (15), indicating that the desired product (5) is produced in this reaction although it can only be isolated in derivatized form.The proposed route for formation of the dimer suggests a general reaction between 1-alkyl-4-bromo-2-nitroimidazoles and strong C- and N-nucleophiles, resulting in substitution at the 5-position.
- Palmer, Brian D.,Denny, William A.
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- Azoles. Part 4. Nucleophilic Substitution Reactions of Halogenoimidazoles
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A number of N-protected derivatives of 2,4,5-tribromoimidazole, 4(5)-bromo-5(4)-nitroimidazole, and 2,4(5)-dibromo-5(4)-nitroimidazole have been prepared by standard procedures and treated with various nucleophiles.Whereas 2,4,5-tribromo (and tri-iodo)imidazole reacted with sodium benzenethiolate to give the corresponding 4,5-dihalogenoimidazole and diphenyl disulphide, 1-protected derivatives of 2,4,5-tribromoimidazole reacted with various sodium alkane (or arene)thiolates and with sodium isopropoxide, in isoprpopyl alcohol, by displacement of the 2-bromine atom. 1-Benzyl-5-bromo-4-nitroimidazole (14), 2-(5-bromo-4-nitroimidazol-1-yl)acetate (25), and 5-bromo-4-nitro-1-phenacylimidazole (26) reacted by displacement of the 5-bromine atom.The product arising from reaction of the last compound with ethyl 2-mercaptoacetate in ethanol in the presence of base, cyclised to give ethyl 3-hydroxy-7-nitro-3-phenylimidazolothiazine-2-carboxylate (35).
- Iddon, Brian,Khan, Nazir,Lim, Bee Lan
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p. 1437 - 1444
(2007/10/02)
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- Conversion of hydroxyl groups into bromo groups in carbohydrates with inversion of configuration
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A novel reagent system is described for the efficient, one-step transformation of hydroxyl groups in carbohydrates to bromodeoxy groups.The reaction proceeds with inversion of configuration.The reagent system consists of triphenylphosphine, tribromoimidazole, and imidazole in toluene at elevated temperature.The carbohydrate need not be soluble in toluene.The examples given include substitution of isolated primary and secondary hydroxyl groups in otherwise protected carbohydrates as well as disubstitution involving one primary and one secondary position in hexopyranosides.High yields are obtained in the replacement of hydroxyl by brommine in the 2-position of 3,4,6-protected methyl α-D-gluco- and -mannopyranosides.
- Classon, Bjoern,Garegg, Per J.,Samuelsson, Bertil
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p. 339 - 343
(2007/10/02)
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