- Structural Dependence of the Ising-type Magnetic Anisotropy and of the Relaxation Time in Mononuclear Trigonal Bipyramidal Co(II) Single Molecule Magnets
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This paper describes the correlation between Ising-type magnetic anisotropy and structure in trigonal bipyramidal Co(II) complexes. Three sulfur-containing trigonal bipyramidal Co(II) complexes were synthesized and characterized. It was shown that we can engineer the magnitude of the Ising anisotropy using ligand field theory arguments in conjunction with structural parameters. To prepare this series of compounds, we used, on the one hand, a tetradentate ligand containing three sulfur atoms and one amine (NS3tBu) and on the other hand three different axial ligands, namely, Cl-, Br-, and NCS-. The organic ligand imposes a trigonal bipyramidal arrangement with the three sulfur atoms lying in the trigonal plane with long Co-S bond distances. The magnetic properties of the compounds were measured, and ab initio calculations were used to analyze the anisotropy parameters and perform magneto-structural correlations. We demonstrate that a smaller axial zero-field splitting parameter leads to slower relaxation time when the symmetry is strictly axial, while the presence of very weak rhombicity decreases the energy barrier and speeds the relaxation of the magnetization.
- Shao, Feng,Cahier, Benjamin,Rivière, Eric,Guillot, Régis,Guihéry, Nathalie,Campbell, Victoria E.,Mallah, Talal
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Read Online
- Mass spectral studies of silyl derivatives of partially hydrolyzed products of nitrogen mustards: Important markers of nitrogen mustard exposure
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Rationale: Nitrogen mustards (NMs) are vesicant class of chemical warfare agents. From the viewpoint of the Chemical Weapons Convention partially hydrolyzed products of nitrogen mustards (pHpNMs) are considered as important markers of nitrogen mustard exposure. The detection of pHpNMs from biological or environmental samples is highly useful for obtaining forensic evidence of exposure to NMs. Methods: Gas chromatography interfaced with tandem mass spectrometry (GC/MS/MS) is a widely used tool for the identification and sensitive detection of metabolites of NMs in complex matrices. The pHpNMs were derivatized using silylating agents as they are highly polar and non-amenable to GC. The mass spectral studies of these silyl derivatives of pHpNMs were performed using GC/MS/MS in both electron ionization (EI) and chemical ionization (CI) mode. Results: Various approaches have been proposed to assess the fragmentation pathways of the trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBDMS) derivatives of pHpNMs. All the proposed fragmentation pathways were based on the product and/or precursor ion scanning of corresponding ions in both EI and CI mode. In the case of EI, most of the fragmentation pathways involved either α-cleavage or inductive cleavage. Conclusions: This is the first report on the MS study of the silyl derivatives of pHpNMs. The study of the two different derivatives of pHpNMs using both EI- and CI-MS provides a reliable, unambiguous identification of pHpNMs in complex environmental and biomedical matrices (such as plasma and urine) during any verification activities.
- Chandra, Buddhadeb,Sinha Roy, Kanchan,Shaik, Mahabul,Waghmare, Chandrakant,Palit, Meehir
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- A new method for synthesizing flibanserin (by machine translation)
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The invention relates to a new method for synthesizing of flibanserin, which belongs to the technical field of organic synthesis. The invention respectively in order to triethanolamine and between amino benzotrifluoride as the starting material, to prepare the piperazine intermediate; then to the O-phenylene diamine and the original four carbonate as raw material, the preparation of the ethoxy and imidazole intermediate; the obtained piperazine intermediate and benzimidazole intermediate undergo the substitution reaction, and hydrochloric acid deprotection to obtain the target product of flibanserin. The invention has few synthetic steps, few by-products, intermediate products and the target product yield is relatively high, intermediate product 2 - ethoxy and imidazole yield up 94.2%, the target product yield can reach 56.2%, it can be seen, the invention overcomes the substance in the prior art synthesis step is tedious, and more byproducts, target low yield of product defect. In addition, the present invention has a simple structure, high purity of product, the economic and environmental protection industrial line, has a very wide range of use and potential economic benefits. (by machine translation)
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Paragraph 0052; 0058; 0059; 0070; 0074; 0075; 0081; 0085
(2019/02/04)
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- Tris(2-aminoethyl)amine synthesis process
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The invention discloses a tris(2-aminoethyl)amine synthesis process, and belongs to the technical field of compound preparation. The tris(2-aminoethyl)amine synthesis process includes the steps of taking triethanolamine as a starting material, putting the triethanolamine, thionyl chloride and a catalyst DMF in a reactor, heating the three to generate tris(2-chloroethyl)amine hydrochloride, dissolving separated tris(2-chloroethyl)amine hydrochloride concentrate and ammonia water in an organic solvent in a reactor, putting the solution in the reactor, carrying out a reaction while heating to obtain tris(2-aminoethyl)amine hydrochloride, and reacting the tris(2-aminoethyl)amine hydrochloride with sodium hydroxide to obtain the tris(2-aminoethyl)amine. The tris(2-aminoethyl)amine synthesis process has the advantages of short reaction route and high controllability.
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Paragraph 0020; 0024-0032
(2019/03/31)
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- Preparation method of tris(2-aminoethyl)amine
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The invention discloses a preparation method of tris(2-aminoethyl)amine, and belongs to the technical field of compound preparation. According to the method, trolamine is used as starting materials; firstly, the trolamine, thionyl chloride and catalysts DMF are put into a reactor; under the heating conditions, tris(2-chloroethyl)amine hydrochloride is generated; then, the purified tris(2-chloroethyl)amine hydrochloride and ammonium hydroxide are dissolved into an organic solvent and put into the reactor; reaction is performed under the heating condition to obtain the tris(2-aminoethyl)amine hydrochloride; finally, the tris(2-aminoethyl)amine hydrochloride reacts with sodium hydroxide to obtain tris(2-aminoethyl)amine. The reaction route is short; the controllability is high.
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Paragraph 0025; 0026; 0028; 0029; 0031; 0032
(2019/04/13)
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- Preparation method of tris(2-chloroethyl)amine hydrochloride
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The invention discloses a preparation method of tris(2-chloroethyl)amine hydrochloride; in particular, in the method, triethanolamine is used as a raw material, Lewis acid is used as a catalyst, hydrogen chloride is used as a chlorination reagent, and tris(2-chloroethyl)amine hydrochloride is prepared through a substitution reaction. The method has a company by-product of hydrogen chloride, the raw materials are easy to obtain, the reaction is fast, the yield and purity of the product are high, and the by-product hydrogen chloride is used as a chlorination agent instead of sulfoxide chloride,so as to avoid the formation of polluted gas sulfur dioxide and the like and greatly reduce the environmental pollution.
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Paragraph 0017; 0018; 0019; 0020; 0021; 0022; 0023
(2018/07/06)
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- Cyclic process for the production of taurine from alkali isethionate and alkali vinyl sulfonate
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The present invention discloses a cyclic process for the production of taurine from alkali isethionate and alkali vinyl sulfonate in a high overall yield of greater than 95% by continuously converting the byproducts of the ammonolysis reaction, sodium ditaurinate and sodium tritaurinate, to sodium taurinate. Pure sodium ditaurinate and sodium tritaurinate are prepared from diethanolamine and triethanolamine as starting materials, respectively, and are subjected to the ammonolysis reaction to yield a mixture of sodium taurinate, sodium ditaurinate, and sodium tritaurinate.
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Paragraph 0050
(2015/11/23)
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- MULTIVALENT SIALIC ACID DERIVATES
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Disclosed is tri- or tetravalent sialic acid derivatives comprising a core moiety to which 3 or 4 sialic acid residues are connected via a linker. Such derivatives inhibit the binding of adenovirus to human cells, whereby infections, such as epidemic keratoconjunctivitis, may be treated or prevented by administration of the tri- or tetravalent sialic acid derivatives.
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Page/Page column 33
(2015/03/16)
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- Triazole linker-based trivalent sialic acid inhibitors of adenovirus type 37 infection of human corneal epithelial cells
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Adenovirus type 37 (Ad37) is one of the principal agents responsible for epidemic keratoconjunctivitis (EKC), a severe ocular infection that remains without any available treatment. Recently, a trivalent sialic acid derivative (ME0322, Angew. Chem. Int. Ed., 2011, 50, 6519) was shown to function as a highly potent inhibitor of Ad37, efficiently preventing the attachment of the virion to the host cells and subsequent infection. Here, new trivalent sialic acid derivatives were designed, synthesized and their inhibitory properties against Ad37 infection of the human corneal epithelial cells were investigated. In comparison to ME0322, the best compound (17a) was found to be over three orders of magnitude more potent in a cell-attachment assay (IC50 = 1.4 nM) and about 140 times more potent in a cell-infection assay (IC50 = 2.9 nM). X-ray crystallographic analysis demonstrated a trivalent binding mode of all compounds to the Ad37 fiber knob. For the most potent compound ophthalmic toxicity in rabbits was investigated and it was concluded that repeated eye administration did not cause any adverse effects.
- Caraballo, Rémi,Saleeb, Michael,Bauer, Johannes,Liaci, A. Manuel,Chandra, Naresh,Storm, Rickard J.,Fr?ngsmyr, Lars,Qian, Weixing,Stehle, Thilo,Arnberg, Niklas,Elofsson, Mikael
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p. 9194 - 9205
(2015/09/07)
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- Tuning the Ising-type anisotropy in trigonal bipyramidal Co(II) complexes
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This paper demonstrates the engineering and tuning of Ising-type magnetic anisotropy in trigonal bipyramidal Co(ii) complexes. Here, we predict that employing a ligand that forces a trigonal bipyramidal arrangement and has weak equatorial σ-donating atoms, increases (in absolute value) the negative zero field splitting parameter D. With these considerations in mind, we used a sulfur containing ligand (NS3iPr), which imposes a trigonal bipyramidal geometry to the central Co(ii) ion with long equatorial Co-S bonds. The resulting complex exhibits a larger anisotropy barrier and a longer relaxation time in comparison to the complex prepared with a nitrogen containing ligand (Me6tren).
- Shao, Feng,Cahier, Benjamin,Guihéry, Nathalie,Rivière, Eric,Guillot, Régis,Barra, Anne-Laure,Lan, Yanhua,Wernsdorfer, Wolfgang,Campbell, Victoria E.,Mallah, Talal
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supporting information
p. 16475 - 16478
(2015/11/18)
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- Anion complexation with cyanobenzoyl substituted first and second generation tripodal amide receptors: Crystal structure and solution studies
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Anion complexation properties of two new tripodal amide receptors have been extensively studied here. Two tripodal receptors have been synthesized from the reaction of cyanobenzoyl acid chloride with two tri-amine building blocks such as (i) tris(2-aminoethyl)amine and (ii) tris(2-(4-aminophenoxy)ethyl)amine, which resulted in the first (L1) and second (L2) generation tripodal amides respectively. A detailed comparison of their coordination behavior with anions is also described by crystallographic and solution state experiments. The crystal structure demonstrates various types of spatial orientations of tripodal arms in two receptors and concomitantly interacts with anions distinctively. Intramolecular H-bonding between amide N-H and C=O prevents opening of the receptor cavity in the crystal, which leads to a locked conformation of L1 having C3v symmetry and makes amide hydrogen unavailable for the anion which results in side cleft anion binding. However, in L2 we conveniently shift the anion binding sites to a distant position which increases cavity size as well as rules out any intramolecular H-bonding between amide N-H and C=O. The crystal structure shows a different orientation of the arms in L2; it adopts a quasi-planar arrangement with C2v symmetry. In the crystal structure two arms are pointed in the same direction and while extending the contact the third arm is H-bonded with the apical N-atom through a -CN group, making a pseudo capsular cavity where the anion interacts. Most importantly spatial reorientation of the receptor L2 from a C2v symmetry to a folded conformation with a C3v symmetry was observed only in the presence of an octahedral SiF62- anion and forms a sandwich type complex. Receptors L1 and L2 are explored for their solution state anion binding abilities. The substantial changes in chemical shifts were observed for the amide (-NH) and aromatic hydrogen (-CH) (especially for F-), indicating the role of these hydrogens in anion binding. The anion interacts with receptor L2 more strongly than L1 as confirmed by 1H NMR titration upon monitoring the -NH signal.
- Hoque, Md. Najbul,Gogoi, Abhijit,Das, Gopal
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supporting information
p. 15220 - 15231
(2015/09/01)
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- Synthesis of triazole cages containing C3-symmetric α-cyclic tripeptide scaffold
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Two water-soluble C3-symmetric 1,2,3-triazole cages containing α-cyclic tripeptide were efficiently synthesized. The key steps include a click reaction to incorporate l-glutamic or l-aspartic acids to a tripodal linker and a unique one-pot cyclotrimerization.
- Chakraborty, Subrata,Tai, Dar-Fu
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supporting information
p. 2274 - 2276
(2014/04/17)
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- A C 3v-symmetric tripodal urea receptor for anions and ion pairs: Formation of dimeric capsular assemblies of the receptor during anion and ion pair coordination
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A new C3v-symmetric urea-based heteroditopic tripodal receptor capable of recognizing both anions and ion pairs was designed, synthesized, and characterized. The protonated receptor forms a sulfate complex which encapsulates a single DMF in the tripodal cavity of the receptor. However, the SO42- anion is located outside the tripodal cavity and is stabilized by N-H···O hydrogen bonds from the urea functions of four receptor cations. With TBAHSO4 the receptor forms a contact ion pair complex, where both the TBA+ and SO 42- groups are pseudoencapsulated in the tripodal cavity of the protonated receptor. Significantly, the receptor forms a charge-separated polymeric ion pair complex with K+ and HPO42- via formation of a dimeric capsular assembly of the receptor, in which three K+ encapsulated dimeric capsular assemblies interdigitate to form a precise cavity that further encapsulates HPO42-. The receptor also forms an anion complex with CO32- via formation of dimeric capsular self-assembly of the receptor. Solution-state binding studies of the receptor with oxyanions have also been carried out by 1H NMR titration experiments, which show the oxyanion binding trend HCO3- > H2PO4- > HSO4-, whereas no binding with NO3- and ClO4- anions is observed.
- Basu, Arghya,Das, Gopal
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p. 2647 - 2656
(2014/04/17)
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- Recyclable nitrate-templated photochemical [2+2] cycloaddition reaction promoted by a tripodal receptor
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A nitrate-templated stereoselective photochemical [2+2] solid-state synthesis that is promoted by a supramolecular encapsulation/release of the anion template is reported. The complete reaction process with the same nitrate template can be recycled in a repetitive manner. The Royal Society of Chemistry 2013.
- Singh, Ashutosh S.,Sun, Shih-Sheng
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supporting information
p. 10070 - 10072
(2013/10/22)
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- Encapsulation of a discrete cyclic halide water tetramer [X 2(H2O)2]2-, X = Cl -/Br- within a dimeric capsular assembly of a tripodal amide receptor
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A conformationally flexible C3v symmetric N-bridged tripodal amide receptor encapsulates a tetrameric halide water cluster [X 2(H2O)2]2- (X = Cl -/Br-) within its dimeric capsular assembly and forms a non-capsular 1D polymeric assembly with higher homologous iodide anions upon protonation.
- Basu, Arghya,Das, Gopal
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supporting information
p. 3997 - 3999
(2013/07/25)
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- Tris(azidoethyl)amine hydrochloride; A versatile reagent for synthesis of functionalized dumbbell oligodeoxynucleotides
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Triazole-cross-linked oligodeoxynucleotides were synthesized using the Cu(I) catalyzed alkyne-azide cycloaddition with tris(azidoethyl)amine hydrochloride and oligodeoxynucleotides possessing N-3-(propargyl)thymidine at both the 3′- and 5′-termini. Further installation of a functional molecule to the dumbbell oligodeoxynucleotides was achieved by utilizing the remaining azide group.
- Ichikawa, Satoshi,Ueno, Hideaki,Sunadome, Takuya,Sato, Kousuke,Matsuda, Akira
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supporting information
p. 694 - 697
(2013/04/11)
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- Recognition, encapsulation, and selective fluorescence sensing of nitrate anion by neutral C 3-symmetric tripodal podands bearing amide functionality
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A series of neutral C3-symmetric acyclic artificial receptors incorporating amide functionality has been designed, synthesized, and fully characterized. Upon protonation, these conformationally flexible N-bridged tripodal podands 1-5 form in situ cone shape conformation through hydrogen bonding and C-H???π interactions. The protonation-induced interior preorganized cavity is capable of entrapping nitrate anions through the amide N-H bonds to form discrete nitrate complexes (1a-5a), which were fully characterized by NMR, HRESI mass spectra, and single crystal structures. By incorporating suitable fluorophores at each branch of the tripod receptor, the resulting fluorescent receptor 5 selectively recognized nitrate anions by fluorescent quenching in a DMSO solution and displayed one of the highest binding affinities for nitrate anions reported so far in polar media. Receptor 5 represents a unique example of a neutral receptor for the recognition of nitrate anions in polar solvent media by its zwitterionic form. The possible mechanism of proton-induced preorganization of these flexible, acyclic receptors in a convergent cone conformation followed by nitrate complexation has been proposed to rationalize the effective nitrate recognition.
- Singh, Ashutosh S.,Sun, Shih-Sheng
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scheme or table
p. 1880 - 1890
(2012/04/23)
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- A unique aliphatic tertiary amine chromophore: Fluorescence, polymer structure, and application in cell imaging
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Although photoluminescence of tertiary aliphatic amines has been extensively studied, the usage of this fundamental chromophore as a fluorescent probe for various applications has unfortunately not been realized because their uncommon fluorescence is easily quenched, and strong fluorescence has been observed only in vapor phase. The objective of this study is how to retain the strong fluorescence of tertiary amines in polymers. Tertiary amines as branching units of the hyperbranched poly(amine-ester) (HypET) display relatively strong fluorescence (Φ = 0.11-0.43). The linear polymers with tertiary amines in the backbone or as the side group are only very weakly fluorescent. The tertiary amine of HypET is easily oxidized under ambient conditions, and red-shifting of fluorescence for the oxidized products has been observed. The galactopyranose-modified HypET exhibits low cytotoxicity and bright cell imaging. Thus, this study opens a new route of synthesizing fluorescent materials for cell imaging, biosensing, and drug delivery.
- Sun, Miao,Hong, Chun-Yan,Pan, Cai-Yuan
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supporting information
p. 20581 - 20584
(2013/02/22)
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- Narcissistic self-sorting of hydrogen-bonded dimeric capsules formed through self-assembly of flexible tripodal receptors in polar solvents
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Purely hydrogen-bonded dimeric capsule formation through self-sorting of three different tripodal receptors, having similar size and bearing the same functionality, through dynamic self-assembly in polar solvents is reported.
- Singh, Ashutosh S.,Sun, Shih-Sheng
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supporting information; scheme or table
p. 7392 - 7394
(2012/09/25)
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- Synthesis, alkylation activity and physico-chemical evaluation of benzodiazepine linked nitrogen mustard agent to penetrate the blood-brain barrier
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The design of drugs for the chemotherapy of tumours of the central nervous system contains numerous challenges. Most of clinical alkylating anticancer agent, such as nitrogen mustard (mustine) is too polar to cross blood-brain barrier. So it is aimed to link nitrogen mustard to CNS active 1,4-benzodiazepine carrier to obtain CNS active benzodiazepine derivative of nitrogen mustard. The benzodiazepinemustard agent was oily at room temperature and stable when stored at less than 0 °C. Structures of all the synthesized compounds were confirmed by UV, IR and 1H NMR spectroscopy. The in vitro chemical alkylation activity studies (NBP) of benzodiazepine-mustard was comparable to that of N,N-bis-(2-chloroethyl)amino moiety as standard alkylating agent. The log P value of benzo-mustard determined experimentally is significantly higher than nordiazepam. Value of polar surface area for the benzo-mustard agent (35.9 A2) predicts that > 90 % of any amount present in the intestinal tract will be absorbed. The study of some physico-chemical properties calculated by online software such as lipophilicity, log BB (0.295), no. of violation of Lipinski's rule of five (0), number of NH or OH hydrogen bond donors (0) and nON value (4) also indicates that it can be a potential candidate for targeted delivery of nitrogen mustard to the brain for the treatment of brain tumour.
- Singh, Rajesh K.,Prasad, D. N.,Bhardwaj, T. R.
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p. 5605 - 5608,4
(2020/09/15)
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- Synthesis and study of chemical delivery system for targeting nitrogen mustard to the brain
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The aim of the present study is to develop the redox delivery of bis-(2-chloroethyl) amine using nicotinic acid as carrier for the site specific and site enhanced sustained delivery of alkylating anticancer moiety to the brain. Structures of all the synthesized compounds were characterized by UV, IR and 1H NMR techniques. An in vitro chemical oxidation study with silver nitrate of target compound (4) indicates that it can be readily converted into its corresponding salt (3). In vitro kinetic studies of final compound (4) in biological media showed its rate of oxidation followed pseudo-first-order kinetics with very short half-lives in rat plasma, human blood and tissue homogenate. The study of some other physicochemical parameter calculated by online software such as lipophilicity, polar surface area, rule of five, number of NH or OH hydrogen bond donors and nON value indicates that it can be permeable to blood-brain barrier.
- Singh, Rajesh K.,Sumit,Malik, Sapna,Sharma, Deep,Prasad, D. N.,Bhardwaj, T. R.
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p. 5635 - 5638,4
(2020/09/15)
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- Dynamic self-assembly of molecular capsules via solvent polarity controlled reversible binding of nitrate anions with C3 symmetric tripodal receptors
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A series of N-bridgehead tripodal receptors bearing amide functionality is reported which displays reversible binding of nitrate anions via solvent polarity controlled molecular capsule formation through a dynamic self-assembly process. The Royal Society of Chemistry 2011.
- Singh, Ashutosh S.,Sun, Shih-Sheng
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supporting information; scheme or table
p. 8563 - 8565
(2011/09/15)
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- Halide functionality dependent formation of molecular receptors and their ion recognition properties
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The halide functionality on W-bridged tripodal receptors has shown a distinct behavior on their self-assembly structures and binding ability toward HgCl2 and ClO4- anions. The receptors containing fluoro, chloro, and iodo groups crystallized to form hemicarcerands in the solid state, whereas the receptor with a bromo group forms a molecular capsule via C-H-Br and C-H-πinteractions. The cavity of the molecular capsule is tunable and is capable of reversible encapsulating-releasing the guest molecules by pH modulation.
- Singh, Ashutosh S.,Chen, Bo-Yu,Wen, Yuh-Sheng,Tsai, Chiitang,Sun, Shih-Sheng
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body text
p. 1867 - 1870
(2009/09/08)
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- Study of electronic and vibronic contributions to cooperative enhancement of two-photon absorption in multibranched structures
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A series of multibranched benzylidene cyclopentanone dyes with non-conjugated central moiety were synthesized. Their one- and two-photon photophysical properties were systematically studied in comparison with corresponding triphenylamine derivatives. Electronic coupling and vibronic coupling contributions to cooperative enhancement of two-photon absorption in multibranched structure were revealed. The results showed that the crucial contribution for this enhancement was from electronic coupling effect among branches. In addition, no contribution of vibronic coupling was observed. Furthermore, multibranched effect on photosensitizing efficiency of these compounds was investigated by one-photon polymerization and the result indicated the electronic coupling effect was also beneficial to their photosensitizing efficiency. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2009.
- Xue, Jianqiang,Zhao, Yuxia,Wu, Jie,Wu, Feipeng,Fang, Xiangyun
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experimental part
p. 634 - 640
(2009/05/30)
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- Binding of HgCl2 by tripodal ligands controlled by AgPF 6: Receptors for the PF6- anion
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Mercuric chloride can readily enter into the biological cycle where it gets converted into other forms of mercury and causes severe neurotoxic, genotoxic and immunotoxic effects; a number of tripodal ligands have been synthesized that selectively bind mercuric chloride and in the presence of AgPF6, mercury can be removed and supramolecular complexes of the PF6 - anion are formed. The Royal Society of Chemistry.
- Singh, Ashutosh S.,Bharadwaj, Parimal K.
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p. 738 - 741
(2008/09/20)
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- Improved selectivity to orthophosphate, pyrophosphate and triphosphate by adding metal ions to a tripodal ligand
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The strong and selective binding of phosphate (PO), pyrophosphate (PP) and triphosphate (tP) by tripodal ligand N, N, N-tri((2-aminoethyl)thioethyl)-amine (L) has been studied ill aqueous solution at I = 0.1mol dm-3 KNO3 and 25 °C. The interactions between L and the inorganic substrates are described and equilibrium constants for each species formed have been determined. The stability constants of 1:1:1 M (M = Cu2+ or Zn2+):L:S (S = PO, PP, tP) are determined by potentiometric pH titrations. The interactions of Zn(II)/L/phosphate systems and Cu (II)/L/phosphate systems are investigated by 31P NMR and EPR spectra respectively. The results show that metal ion acts as messenger or bridge between the receptor and the substrate, and the existence of metal ion in the ternary systems leads to competition between the mixed ligands. The metal ion improves the selectivity and recognition of the substrates by protonated tripodal ligand.
- Guo, Yan-He,Ge, Qing-Chun,Lin, Hai,Lin, Hua-Kuan,Zhu, Shou-Rong,Zhou, Chang-Yue
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p. 116 - 120
(2007/10/03)
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- Nickel(II) Complexes with Tripodal Ligands: Synthesis, X-Ray Structural and Spectroscopic Studies
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The synthesis, X-ray crystal structures and electronic spectra of two nickel complexes with tripodal ligands are reported.The nickel(II) complex, 1(ClO4)>ClO4, with the ligand, trisethyl>amine L1 crystallizes as purple rectangular parallelopipeds in the monoclinic space group P21/a with a = 9.542(7), b = 28.231(13), c = 11.136(7) Angstroem, β = 91.50(6) deg, Z = 4, R = 0.058 and R'= 0.067 for 2782 reflections.The Ni atom is bound equatorially to two S and two N atoms from arms of the tripod while the two axial positions are occupied by the bridgehead nitrogen and an oxygen from a perchlorate.The complex 2>2 with the ligand trisethyl>amine L2 crystallizes as blue prisms in the monoclinic space group P21/n with a = 11.7923(9), b = 16.813(2), c = 12.716(1) Angstroem, β = 109.567(7) deg, Z = 4, R = 0.039 and R'= 0.060 for 3354 reflections.All the three arms of the ligand are bound to the Ni(II) providing a distorted-octahedral S3N3 donor set.Solution elctronic spectra (in acetonitrile, dimethylformamide or dimethyl sulfoxide) of 2>2 indicate retention of the solid-state structure, whereas for 1(ClO4)>ClO4 bound perchlorate is released in acetonitrile and replaced by solvent.
- Ragunathan, Kaliappa G.,Bharadwaj, Parimal K.
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p. 2417 - 2422
(2007/10/02)
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