7663-91-4Relevant academic research and scientific papers
Homochiral and heterochiral associations observed in crystals of ArSO2-(Aib)5-OMe
Azumaya, Isao,Hikawa, Hidemasa,Kikkawa, Shoko,Okayasu, Misaki,Sato, Naruka,Suzuki, Ayaka,Takahashi, Ayaka,Takahashi, Yoshiki
, p. 8353 - 8361 (2020/12/31)
The molecular conformations, packing structures and intermolecular interactions of homopentapeptides from achiral α-aminoisobutyric acid (Aib), ArSO2-(Aib)5-OMe (Ar = p-tolyl, p-bromophenyl and p-methoxyphenyl), have been investigated by single-crystal X-
Iodine-Catalyzed Synthesis of Chiral 4-Imidazolidinones Using α-Amino Acid Derivatives via Dehydrogenative N-H/C(sp3)-H Coupling
Kanyiva, Kyalo Stephen,Tane, Marina,Shibata, Takanori
, p. 12773 - 12783 (2019/09/09)
An efficient method for the asymmetric synthesis of 4-imidazolidinones via an iodine-catalyzed intramolecular N-H/C(sp3)-H activation of readily available and abundant feedstocks, amino acids, and amines is described. The reaction proceeded under visible light irradiation to afford a variety of 4-imidazolidinone derivatives under mild conditions in moderate to excellent yields. Secondary and tertiary C(sp3)-H bonds were aminated, and various functional groups were tolerated.
Metal-Free N–H/C–H Coupling for Efficient Asymmetric Synthesis of Chiral Dihydroquinoxalinones from Readily Available α-Amino Acids
Kanyiva, Kyalo Stephen,Horiuchi, Masashi,Shibata, Takanori
supporting information, p. 1067 - 1070 (2018/03/06)
We have developed a method for the synthesis of dihydroquinoxalinones via intramolecular N–H/C–H coupling using hypervalent iodine. The starting materials were prepared from inexpensive and readily available aniline and amino acid derivatives. Various functional groups were tolerated to give multisubstituted dihydroquinoxalinones in moderate to excellent yields. The chirality of the amino acid was transferred to the desired target compound without a loss of enantiomeric excess. Preliminary mechanistic studies indicated that the reaction proceeds via an ionic mechanism.
Palladium-catalyzed site-selective hydrogen isotope exchange (HIE) reaction of arylsulfonamides using amino acid auxiliary
Liu, Wei,Xu, Xingyu,Zhao, Hongyan,Yan, Xiaoyu
, p. 4111 - 4118 (2018/06/19)
Hydrogen isotope exchange (HIE) is a versatile method for the introduction of deuterium to organic compounds. Herein, regioselective deuteration of sulfonamides is achieved by palladium-Catalyzed HIE reaction. By using amino acid as weakly coordination-di
α-Amino Acid Sulfonamides as Versatile Sulfonylation Reagents: Silver-Catalyzed Synthesis of Coumarins and Oxindoles by Radical Cyclization
Kanyiva, Kyalo Stephen,Hamada, Daisuke,Makino, Sohei,Takano, Hideaki,Shibata, Takanori
supporting information, p. 5905 - 5909 (2018/09/14)
We developed a silver-catalyzed strategy for the generation of sulfonyl radicals from sulfonamides derived from α-amino acids. The reaction proceeded via a decarboxylation, N–S bond cleavage and radical cyclization sequence and allows the difunctionalization of alkynes and the synthesis of 3-sulfonylated coumarins. The reaction tolerated a broad scope of substrates and functional groups and could be extended to the synthesis of oxindoles and an isoquinolinedione by the capturing of the sulfonyl radical with an alkene moiety. Moreover, the proposed mechanism was supported experimentally and by DFT calculations.
Palladium-Catalyzed Mono-Selective ortho C H Arylation of Aryl Sulfonamides in Water: A Concise Access to Biaryl Sulfoamide Derivatives
Liu, Wei,Wang, Dongyin,Zhao, Yongli,Yi, Fei,Chen, Junmin
supporting information, p. 1968 - 1974 (2016/07/06)
A green atom-economical method for the synthesis of biaryl sulfonamide derivatives via palladium(II)-catalyzed C H bond activation by employing an amino acid moiety as the bidentate directing group has been developed. The protocol proceeded efficiently in water; high yields and broad substrate scope were achieved. The reaction shows good functional group compatibility and proceeds in a highly selective manner at the ortho position of arenes connected to sulfonamide sulfur atoms. This auxiliary can be easily removed either by acidic hydrolysis, or converted into primary biaryl sulfomamides with a 30 mol % amount of CuO as catalyst. Mechanistic studies show that the present bidentate directing group is essential for promoting ortho C H bond activation of arenes connected to sulfonamide sulfur atoms. (Figure presented.) .
Cu(II)-catalyzed decarboxylation/elimination of N-arylsulfonyl amino acids to primary aryl sulfonamides
Zhou, Liandi,Li, Xiaokang,Liu, Wei,Zhao, Yongli,Chen, Junmin
supporting information, p. 1299 - 1306 (2016/08/16)
A novel protocol for CuO-catalyzed decarboxylation/elimination of N-arylsulfonyl amino acids was developed. It is the first example of using an accessible amino acid as an ammonia synthetic equivalent for the synthesis of primary aryl sulfonamides via oxidative decarboxylation/elimination reactions. The present protocol shows excellent functional group tolerance and provides an efficient method for the synthesis of primary aryl sulfonamides in excellent yields.
SYNTHESE VON 2-METHYLALANIN-PEPTIDEN, DIE pH-ABHAENGIGKEIT IHRER 13C-NMR-SPECTREN UND EINE NEUE METHODE ZUR AUSWERTUNG UEBER CS-DIAGRAMME
Leibfritz, Dieter,Haupt, Erhard,Dubischar, Norbert,Lachmann, Heinrich,Oekonomopulos, Raymond,Jung, Guenther
, p. 2165 - 2182 (2007/10/02)
The uncommon amino-acid 2-methylalanine (α-aminoisobutiryc acid, Aib) was investigated by 13C-NMR.The chemical shifts of amino- or carboxy-protected derivates of Aib and of protected oligopeptides are discussed with respect to neighbouring groups and amino acids.The pH-dependence of the 13C-NMR spectra of Aib, Aib-Ala, Ala-Aib, Aib-Ala-Aib and Aib-Ala-Aib-Ala-Aib was studied.Using these examples, a new and advantageous method is demonstrated for the first time for the evaluation of NMR titration curves, which uses so-called chemical shift diagrams (CS diagrams).
