- Development of Decarboxylative Cyanation Reactions for C-13/C-14 Carboxylic Acid Labeling Using an Electrophilic Cyanating Reagent
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Degradation-reconstruction approaches for isotope labeling synthesis have been known for their remarkable efficiency, but applications are scarce due to some fundamental limitations of the chemistries developed to date. The decarboxylative cyanation reaction, as a degradation-reconstruction approach, is especially useful in rapid carboxylic acid carbon isotope labeling, however development toward its application as a widespread technique has stalled at the early stages due to numerous limitations which include somewhat narrow applicability. Employing the electrophilic cyanating reagent N-cyano-N-phenyl-p-toluenesulfonamide (NCTS) as the cyano source, efficient decarboxylative cyanation chemistry has been developed for aryl and alkyl carboxylic acids respectively with two rationally designed reaction pathways. The reactions provided good yields of nitrile products from carboxylic acids, with complete retention of isotopic purity from the [13CN]-NCTS used. The reaction conditions are relatively mild requiring no oxidant and no excess toxic heavy metal and the reagent [13/14CN]-NCTS is a stable, easy-to-handle crystalline solid that can be prepared quickly and effectively from the readily available [13/14C]-KCN. The following work describes this novel and efficient method for alkyl and aryl carboxylic acid isotopic labeling using a single reagent.
- Song, Fengbin,Salter, Rhys,Chen, Lu
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p. 3530 - 3537
(2017/04/11)
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- Synthesis of α-aryl esters and nitriles: Deaminative coupling of α-aminoesters and α-aminoacetonitriles with arylboronic acids
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Transition-metal-free synthesis of α-aryl esters and nitriles using arylboronic acids with α-aminoesters and α-aminoacetonitriles, respectively, as the starting materials has been developed. The reaction represents a rare case of converting C(sp3)-N bonds into C(sp3)-C(sp2) bonds. The reaction conditions are mild, demonstrate good functional-group tolerance, and can be scaled up. Touch base: A transition-metal-free protocol for the synthesis of α-aryl esters and nitriles by deaminative coupling is presented. Strong bases and transition-metal catalysts are not needed. The new synthetic method uses readily available starting materials and demonstrates wide substrate scope.
- Wu, Guojiao,Deng, Yifan,Wu, Chaoqiang,Zhang, Yan,Wang, Jianbo
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supporting information
p. 10510 - 10514
(2016/02/18)
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- Synthesis, selective aldose reductase inhibitory profile and antihyperglycaemic potential of certain parabanic acid derivatives
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Synthesis and aldose reductase inhibitory profile of certain parabanic acid derivatives 1a-p is described. Also, the antihyperglycaemic potential of these compounds was studied. The most active inhibitors in this series were compounds 1 g, 1p, and 1o which showed inhibitory activity, 36.6, 90 and 91% respectively, at concentration 1 × 10-4. Their IC50 were 2 × 10-6, 7.5 × 10-8 and 5 × 10-8, respectively. Compound 1o exhibited pronounced antihyperglycaemic effect.
- Nabil Aboul-Enein,El-Azzounya,Maklad,Attia,Wiese
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p. 329 - 350
(2007/10/03)
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- Towards the synthesis of aminodibenzo[b,e][1,4]dioxin derivatives via cationic ruthenium complexes
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Double nucleophilic aromatic substitution reactions between N-substituted (η6-1,2-dichlorobenzene)RuCp+ salts and substituted 1,2-benzenediols have been carried out under mild conditions to prepare N-substituted (η6-dibenzo[b,e][1,4]dioxin)ruthenium(II) complexes. The dibenzodioxin ligands were subsequently liberated by photolysis, with radiation from a sunlamp or from a medium pressure Hg lamp (300 nm).
- Cambie, Richard C.,Clark, George R.,Coombe, Sheryl L.,Coulson, Sally A.,Rutledge, Peter S.,Woodgate, Paul D.
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- METABOLISM OF CHLOROPHENYLALANINES IN CROP AND WEED PLANTS IN RELATION TO THE FORMATION OF POTENTIAL HERBICIDAL END PRODUCTS
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Metabolism of 12 synthetic D,L-chlorophenylalanines has been examined in several crop and weed plants.Twenty-five gram samples of excised shoots or leaves of bushbean, soybean, corn, pigweed, lambsquarters, and giant foxtail were allowed to metabolize 10-4 M solutions of the D,L-chlorophenylalanines for 24 hr in continuous light.The plant samples were then extracted in 80percent methanol and the soluble acidic metabolites fractionated into ether.Each ether concentrate was partially purified by fractional elution from a PrepSep C18 coloumn and then analysed by HPLC.Collected fractions were esterified with pentafluorobenzylbromide and examined by GC-MS to demonstrate the presence of PFB-esters of chlorophenylacetic, chlorobenzoic and/or chlorocinnamic acids.Since certain of these metabolites are known to be potent plant growth-regulators and herbicides, the results are discussed in relation to the potantial herbicidal action of certain chlorophenylalanines by the mechanism of 'lethal synthesis'.Key Word Index - Phaseolus vulgaris; Glycine max.; Leguminosae; Zea mays; Amaranthus retroflexus; Chenopodium album; Setaria faberii; metabolism; D,L-chlorophenylalanines; chlorophenylacetic acids; chlorobenzoic acids; chlorocinnamic acids; growth regulators.
- Taylor, David C.,Wightman, Frank,Kazakoff, Clem W.
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