Simple and scalable electrochemical synthesis of 2,1-benzisoxazoles and quinoline N-oxides.
Cathodic reduction of the nitro moiety and subsequent intramolecular cyclization affords different substituted 2,1-benzisoxazoles and quinoline N-oxides. This methodology allows the synthesis of two different types of heterocycles from common simple starting materials, using electrons as a sole reagent for this transformation. The electrolysis can be conducted in a very simple undivided electrolysis cell under constant current conditions. This permits working on a larger scale compared to other electrochemical methodologies and represents a significant advantage.
Preparative-Scale Synthesis of Vedejs Chiral DMAP Catalysts
A scalable synthesis of chiral Vedejs-type DMAP catalysts is reported. The key step of the synthesis is amination of the enantiomerically pure 4-chloropyridine derivative using well-defined ZnCl2(amine)2 complexes. A series of Zn(II)–amine complexes have been synthesized to explore the scope of the ZnCl2-mediated amination of 4-halopyridines. Mechanistic studies support a Zn(II)-facilitated nucleophilic aromatic substitution as a plausible mechanism for the chlorine-to-amine exchange.
Development of a Chiral DMAP Catalyst for the Dynamic Kinetic Resolution of Azole Hemiaminals
A new catalyst for the dynamic kinetic resolution of azole hemiaminals has been developed using late-stage structural modifications of the tert-leucinol-derived chiral subunit of DMAP species.
Acylative Dynamic Kinetic Resolution of Secondary Alcohols: Tandem Catalysis by HyperBTM and Bäckvall's Ruthenium Complex.
Non-enzymatic dynamic kinetic resolution (DKR) of secondary alcohols by enantioselective acylation using an isothiourea-derived HyperBTM catalyst and racemization of slowly reacting alcohol by Backvall's ruthenium complex is reported. The DKR approach features high enantioselectivities (up to 99:1), employs easy-to-handle crystalline 4-nitrophenyl isobutyrate as the acylating reagent, and proceeds at room temperature and under an ambient atmosphere. The stereoinduction model featuring cation-π system interactions between the acylated HyperBTM catalyst and π electrons of an alcohol aryl subunit has been elaborated by DFT calculations.
N‐Terminal Modification of Gly‐His‐Tagged Proteins with Azidogluconolactone
Site-specific protein modifications are vital for biopharmaceutical drug development. Gluconoylation is a non-enzymatic, post-translational modification of N-terminal HisTags. We report high-yield, site-selective inâ vitro α-aminoacylation of peptides, glycoproteins, antibodies, and virus-like particles (VLPs) with azidogluconolactone at pHâ 7.5 in 1â h. Conjugates slowly hydrolyse, but diol-masking with borate esters inhibits reversibility. In an example, we multimerise azidogluconoylated SARS-CoV-2 receptor-binding domain (RBD) onto VLPs via click-chemistry, to give a COVID-19 vaccine. Compared to yeast antigen, HEK-derived RBD was immunologically superior, likely due to observed diffe…
CCDC 1875521: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687
CCDC 1875522: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687
CCDC 1528810: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Marcis Sejejs, Adam S. Kamlet, David W. Piotrowski, Edwin Vedejs, Edgars Suna|2017|J.Org.Chem.|82|869|doi:10.1021/acs.joc.6b02955
CCDC 1528809: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Marcis Sejejs, Adam S. Kamlet, David W. Piotrowski, Edwin Vedejs, Edgars Suna|2017|J.Org.Chem.|82|869|doi:10.1021/acs.joc.6b02955
CCDC 1875523: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687
CCDC 1875525: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687
CCDC 1875524: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687