When an electrochemical method is tentatively applied for N-alkylation of proteins, some Maillard reactions occur on the counter electrode. A low level of reductive N-alkylation of casein was obtained on a cathodic electrode, but the method unfortunately remains poorly efficacious in comparison with those using a hydride donor such as sodium cyanoborohydride. Electroassisted reductive N-alkylation is suitable only for basic proteins such as histones or lysozyme. For other proteins, an alternative consists of either methylating carboxylic residues to increase the value of their isoelectric pH or coating them with a cationic detergent.
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http://dx.doi.org/10.1021/jf980861f | DOI Listing |
J Org Chem
December 2024
College of Chemistry and Chemical Engineering, Green Catalysis & Synthesis Key Laboratory of Xinyang City, Xinyang Normal University, Xinyang, Henan 464000, China.
An unprecedented, transition metal-free -alkylation of disulfides with alkyl halides is developed for the first time, providing an efficient and green synthesis of thioethers and even thioesters. Notably, this new method allows the full utilization of both sulfur atoms of disulfides under chemical reductant-free conditions and can be easily scaled up in gram scale, showing good practical value. Control experiments suggested that water, unprecedentedly, serves as the terminal reductant of the whole reaction.
View Article and Find Full Text PDFChem Sci
August 2024
Yusuf Hamied Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
The development of methods for the assembly of secondary α-alkyl amines remains a central challenge to chemical synthesis because of their critical importance in modulating the physical properties of biologically active molecules. Despite decades of intensive research, chemists still rely on selective N-alkylation and carbonyl reductive amination to make most amine products. Here we report the further evolution of a carbonyl alkylative amination process that, for the first time, brings together primary amines, aldehydes and alkyl iodides in a visible-light-mediated multicomponent coupling reaction for the synthesis of a wide range of α-branched secondary alkylamines.
View Article and Find Full Text PDFJ Am Chem Soc
August 2024
Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, Aachen 52056, Germany.
Amide alkylation is a fundamental process in organic chemistry. However, the low nucleophilicity of amides means that divergent coupling with alkyl electrophiles is often not achievable. To circumvent this reactivity challenge, individual amine synthesis followed by amidation with standard coupling agents is generally required.
View Article and Find Full Text PDFJ Org Chem
August 2024
Department of Chemistry, Indian Institute of Technology, Guwahati, Assam 781039, India.
A sustainable catalytic synthesis of selective monoalkylated amines from nitroarenes and alcohols by new palladium(II)-NNO pincer-type complexes has been described. Herein, a series of Pd(II) complexes [Pd(NNO)PPh] (-) are synthesized and characterized by analytical and spectroscopic (IR, NMR, and HR-MS) methods. The solid-state molecular structures of two complexes are established by X-ray single-crystal diffraction.
View Article and Find Full Text PDFNucleic Acids Res
August 2024
Department of Chemistry, University of Illinois Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA.
DNA and RNA nucleobase modifications are biologically relevant and valuable in fundamental biochemical and biophysical investigations of nucleic acids. However, directly introducing site-specific nucleobase modifications into long unprotected oligonucleotides is a substantial challenge. In this study, we used in vitro selection to identify DNAzymes that site-specifically N-alkylate the exocyclic nucleobase amines of particular cytidine, guanosine, and adenosine (C, G and A) nucleotides in DNA substrates, by reductive amination using a 5'-benzaldehyde oligonucleotide as the reaction partner.
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