10199-89-0Relevant academic research and scientific papers
Kinetic and equilibrium studies of the reactions of 4-nitrobenzo-furazan and some derivatives with sulfite ions in water. Evidence for the Boulton-Katritzky rearrangement in a σ-adduct
Crampton, Michael R.,Pearce, Lyndsey M.,Rabbitt, Lynsey C.
, p. 257 - 261 (2002)
The reactions with sulfite ions in water of 4-nitrobenzofurazan, 1, 4-nitrobenzofuroxan, 2, and three 4-nitro-7-substituted benzofurazans have been examined by 1H NMR spectroscopy and stopped-flow spectrophotometry. For each substrate the initial reaction occurs at the 5-position to give σ-adducts which have considerably higher thermodynamic stability than the corresponding adduct of 1,3,5-trinitrobenzene. In the cases of 1 and 2 isomerisation of the 5-adducts occurs slowly to yield adducts carrying sulfite at the 7-position. 1H NMR measurements on 2 labelled with 15N provide evidence that here the rearrangement involves an intramolecular Boulton-Katritzky mechanism.
Energy down converting organic fluorophore functionalized mesoporous silica hybrids for monolith-coated light emitting diodes
B?rgardts, Markus,Müller, Thomas J. J.
, p. 768 - 778 (2017)
The covalent attachment of organic fluorophores in mesoporous silica matrices for usage as energy down converting phosphors without employing inorganic transition or rare earth metals is reported in this article. Triethoxysilylpropyl-substituted derivatives of the blue emitting perylene, green emitting benzofurazane, and red emitting Nile red were synthesized and applied in the synthesis of mesoporous hybrid materials by postsynthetic grafting to commercially available MCM-41. These individually dye-functionalized hybrid materials are mixed in variable ratios to furnish a powder capable of emitting white light with CIE chromaticity coordinates of x = 0.33, y = 0.33 and an external quantum yield of 4.6% upon irradiation at 410 nm. Furthermore, as a proof of concept two different device setups of commercially available UV light emitting diodes, are coated with silica monoliths containing the three triethoxysilylpropyl-substituted fluorophore derivatives. These coatings are able to convert the emitted UV light into light with correlated color temperatures of very cold white (41100 K, 10700 K) as well as a greenish white emission with correlated color temperatures of about 5500 K.
Reactions of substituted phenylnitromethane carbanions with aromatic nitro compounds in methanol: Carbanion reactivity, kinetic, and equilibrium studies
Asghar, Basim H.
, p. 477 - 488 (2014/07/08)
The feasibility of carrying out nucleophilic addition from electron-deficient heteroaromatics has been addressed through a detailed investigation of the interaction of a two 7-substituted-nitrobenzofurazan (R = OMe 2a; R = Cl 2b) with a series of substituted-nitroaryl anions (X = 4-NO 2 1a; X = 3-NO2 1b; X = 4-CN 1c; X = 4-Br 1d), all reactions first lead to the quantitative formation of the σ-adducts 3a-d and 4a-d arising from covalent addition of the nucleophile to the C-5 carbon. The rate and equilibrium constants for the formation of σ-adducts 3a-d and 4a-d (k5, K5) together with the rate constants for their decomposition (k-5) have been determined in methanol at 25C, allowing a determination of intrinsic rate constants, k0 = 0.03, the lower k0 value reflects the very strong salvation by methanol of the negative charge on the nitro group. The discovery of a linear correlation between the E and pKaMeOH parameters allows a calibration of the electrophilicity power of 2a and 2b, E = -11.67 and -10.29, respectively. Applying the general approach to nucleophilicity/electrophilicity recently developed by Mayr et al. through the relationship log k = s(E + N), a successful ranking of our nitroaryl anions 1a-d on the general nucleophilicity scale (N) has been carried out. The N values of 1a-d are found to cover a range from 15.78 to 16.69. The results are compared with previously reported data in water and DMSO.
Improved synthesis of 4-amino-7-nitrobenz-2,1,3-oxadiazoles using NBD fluoride (NBD-F)
Jung, Michael E.,Dong, Timothy A.,Cai, Xiaolu
, p. 2533 - 2535 (2011/06/21)
The 7-nitrobenz-2,1,3-oxadiazole (NBD) unit is a highly useful fluorescent tag with wide application in biology. Installation of the NBD group typically proceeds via the SNAr reaction between an amine and an NBD halide. Herein, we demonstrate that NBD-F 1 results in significantly higher yields than NBD-Cl 2, and that triethylamine in dimethylformamide at 23 °C overnight is a broadly applicable set of conditions for this reaction. In particular, the highly useful fluorescent carbohydrate 2-NBD-glucosamine (2-NBDG, 3) can now be prepared in 75% yield with NBD-F as compared to 12% with NBD-Cl.
Agent and method for dyeing keratin fibers
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, (2008/06/13)
The present invention relates to a fiber-dyeing agent (A) prepared by mixing two components (A1) and (A2), said agent being characterized in that component (A1) contains at least one compound of formula (I) 1wherein X denotes a halogen atom, a methoxy group or an ethoxy group; Y denotes an oxygen atom, a sulfur atom or a selenium atom; R1 and R2 are equal or different and independently of each other denote hydrogen, a halogen atom, a (C1-C4)-alkyl group, a halogen-substituted (C1-C4)-alkyl group, a (C1-C4)-alkoxy group, a nitro group, an acetamido group or an NRaRb group, wherein the Ra and Rb groups are equal or different and independently of each other denote hydrogen, a (C1-C4)-alkyl group, an optionally substituted aromatic carbon ring or a (C1-C4)-alkanecarbonyl group, or Ra and Rb together with the nitrogen atom form a heterocyclic (C3-C6) group, and component (A2) contains at least one compound from the group consisting of amines, aminonitrobenzenes and phenols; to a method for dyeing hair by use of said agent, and to a multicomponent kit.
Compositions and methods for treatment of neoplastic disease
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, (2008/06/13)
The present invention comprises compositions and methods for treating a tumor or neoplastic disease in a host, The methods employ conjugates comprising superantigen polypeptides, nucleic acids with other structures that preferentially bind to tumor cells and are capable of inducing apoptosis. Also provided are superantigen-glycolipid conjugates and vesicles that are loaded onto antigen presenting cells to activate both T cells and NKT cells. Cell-based vaccines comprise tumor cells engineered to express a superantigen along with glycolipids products which, when expressed, render the cells capable of eliciting an effective anti-tumor immune response in a mammal into which these cells are introduced. Included among these compositions are tumor cells, hybrid cells of tumor cells and accessory cells, preferably dendritic cells. Also provided are tumoricidal T cells and NKT cells devoid of inhitory receptors or inhibitory signaling motifs which are hyperresponsive to the the above compositions and lipid-based tumor associated antigens that can be administered for adoptive immunotherapy of cancer and infectious diseases.
