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Reagent

About: Reagent is a research topic. Over the lifetime, 60091 publications have been published within this topic receiving 1234928 citations. The topic is also known as: reagens.


Papers
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Journal ArticleDOI
TL;DR: In this article, the triisopropylsilyl (TIPS) enol ethers were treated with PhIO/TMSN3/at −18 to −15 °C rapidly (5 min) with only traces of the α-azido adduct.
Abstract: Treatment of triisopropylsilyl (TIPS) enol ethers with PhIO/TMSN3/at −18 to −15 °C rapidly (5 min) gave β-azido TIPS enol ethers in high yields, with only traces of the α-azido adduct. The reaction...

133 citations

Journal ArticleDOI
TL;DR: Some organoaluminum compounds, especially methylaluminoxane, are capable of AlkDF with more reactive substrates, but catalysis by alumenium offers an advantage over the uncatalyzed C-F activation in terms of both increased rate and, in some cases, a dramatically increased selectivity.
Abstract: Dialkylalumenium cation equivalents coupled with the hexabromocarborane anion function as efficient and long-lived catalysts for alkylation of aliphatic C-F bonds (alkylative defluorination or AlkDF) by alkylaluminum compounds. Only C(sp(3))-F bonds undergo AlkDF; C(sp(2))-F bonds are unaffected. Examples of compounds undergoing AlkDF include monofluoroalkanes, gem-difluorocyclopentane, and compounds containing a CF(3) group attached to either an aryl or an alkyl substituent. Conversion of C-F bonds to C-Me bonds is accomplished with high fidelity using Me(3)Al as the stoichiometric reagent. In reactions with Et(3)Al, hydrodefluorination of the C-F bonds is competitive with alkylation, indicative presumably of competitive hydride vs alkyl transfer from Et(3)Al. In a trialkylaluminum reagent, 1.1-1.4 alkyl groups per Al can be used to replace C-F bonds. Organoaluminum compounds efficiently remove water from the reaction mixture, obviating the need for rigorously dry solvents. Some organoaluminum compounds, especially methylaluminoxane, are capable of AlkDF with more reactive substrates, but catalysis by alumenium offers an advantage over the uncatalyzed C-F activation in terms of both increased rate and, in some cases, a dramatically increased selectivity.

133 citations

Journal ArticleDOI
TL;DR: In this article, a rapid method, of improved accuracy, for the determination of nitrate and nitrite in meat products is described, which is based on reduction to nitrite with cadmium, and subsequent development of the dye Orange I obtained with I-naphthol/sulphanilic acid reagent.
Abstract: A rapid method, of improved accuracy, for the determination of nitrate and nitrite in meat products is described. Nitrate is determined by reduction to nitrite with cadmium, and subsequent development of the dye Orange I obtained with I-naphthol/sulphanilic acid reagent. Nitrite present does not interfere and is separately determined with the same colorimetric reagent. In meat, a range of concentrations of nitrate and nitrite up to the equivalent of 2000 p.p.m. sodium nitrite may be determined.

133 citations

Journal ArticleDOI
TL;DR: Both aliphatic and aromatic nitriles are conveniently and selectively converted in a single step, via an indirect acid-catalyzed hydration, into the corresponding amides in 1-8 h using a TFA-H2SO4 mixture as a reagent system.
Abstract: Both aliphatic and aromatic nitriles are conveniently and selectively converted in a single step, via an indirect acid-catalyzed hydration, into the corresponding amides in 1-8 h using a TFA-H 2 SO 4 mixture as a reagent system. Although the same reagent did not work for the sterically hindered nitriles such as mesitonitrile, the transformation could be accomplished by changing TFA to AcOH at higher temperatures (>90 °C).

133 citations

Patent
18 Jun 2004
TL;DR: The inventive test strip as discussed by the authors includes a reagent layer that extends across the width of the test strip and also extends to the sample-receiving end, such that the edges of the Reagent layer are aligned with the side and dose receiving edges of a test strip.
Abstract: A test strip having a small sample-receiving chamber on the order of less than 1 microliter. The inventive test strip includes a reagent layer that extends across the width of the test strip and also extends to the sample-receiving end, such that the edges of the reagent layer are aligned with the side and dose receiving edges of the test strip. The hydrophilic reagent extending to the dosing edge of the strip promotes wicking of the sample into the test strip. The end and side edges of the reagent layer are preferably formed as part of a cutting process that forms individual test strips from a larger web, which results in a smooth and thin reagent layer with a uniform thickness, substantially covering the entire floor of the sample-receiving chamber. The inventive mass production process helps improve the reproducibility of the quantity, location, thickness and other properties of the reagent layer, which in turn improves the accuracy of the test result.

133 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20232,117
20224,093
2021785
20201,317
20191,860
20182,158