- Single Electron Transfer-Induced Selective α-Oxygenation of Glycine Derivatives
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Modification of amino acids is an important strategy in organic and bioorganic chemistry. In contrast to common side-chain functionalization, backbone modification is much less explored. Especially glycine units seem to be attractive and versatile since a wide range of functionality can be potentially introduced. We report here oxidative modification of glycinates that are stable and enable further functionalization. Selective glycinate enolate oxidation by TEMPO or a FeCp2PF6/TEMPO reagent combination provides stable alkoxyamines in good to excellent yields. The methodology is expanded to glycine-containing dipeptides demonstrating selective oxygenation at the glycine unit. The orthogonal reactivity potential of oxygenated glycines for transformation to other amino acid derivatives is explored.
- Venugopal, Navyasree,Moser, Johannes,Vojtí?ková, Margaréta,Císa?ová, Ivana,K?nig, Burkhard,Jahn, Ullrich
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supporting information
p. 405 - 412
(2021/11/03)
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- Synthesis and antimicrobial activities of novel sorbic and benzoic acid amide derivatives
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A series of sorbic and benzoic acid amide derivatives were synthesized by conjugating sorbic acid (SAAD, a1–a7) or benzoic acid (BAAD b1–b6) with amino acid esters and their antimicrobial activities were investigated against Escherichia coli, Bacillus subtilis and Staphylococcus aureus, mixed bacteria from rancid milk, Saccharomyces cerevisiae, and Aspergillus niger. The antimicrobial activity of sorbic acid amides was better than that of benzoic acid amides. The minimum inhibitory concentrations (MIC) of compound isopropyl N-[1-oxo-2, 4-hexadien-1-yl]-L-phenylalaninate (a7) were 0.17 mM against B. subtilis, and 0.50 mM against S. aureus, while the MIC values of sorbic acid were more than 2 mM respectively. Also, compound a7 displayed pH-independent antimicrobial activity in the range of pH 5.0–9.0 and was effective at pH 9.0. These results demonstrated that the conjugation of sorbic acid with amino acid esters led to significant improvement of in vitro antimicrobial attributes, but little effect was observed for benzoic acid amide derivatives.
- Wei, Qingyi,Wang, Xiaomei,Cheng, Jun-Hu,Zeng, Guangxiang,Sun, Da-Wen
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p. 220 - 232
(2018/06/26)
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- Esterification in dry media using ferric perchlorate adsorbed on silica gel
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Adsorption of Fe(ClO4)3(H2O)6 onto chromatographic grade silica gel in the presence of alcohol ( to be used for esterification ) produces a supported reagent, Fe(ClO4)3(ROH)6/SiO2. This reagent, has been found effective for the rapid and high yield of esters, on grinding in the presence of carboxylic acids using pestle and mortar in the solid state.
- Parmar, Anupama,Kaur, Jatinder,Goyal, Rita,Kumar, Baldev,Kumar, Harish
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p. 2821 - 2826
(2007/10/03)
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