A study of the structural parameters which govern the supramolecular organization of an organogelator built from the Disperse Red moiety is proposed. In particular, the key balance between intermolecular H-bonding and/or π-π interactions is addressed by comparing the effect of a secondary amide vs. an ester linker within the molecular structure. Solution H-NMR studies show the superiority of the former interaction in promoting the nanostructuring process, allowing it to reach a gel state in toluene. The nanostructures obtained from both the amide and the ester derivatives were also studied in the solid state. In particular, the use of second-harmonic generation microscopy demonstrates that an anisotropic organization of the material can even be observed in the case of the ester derivative, which demonstrates the efficiency of the tris(alkoxy)benzene unit in directing the self-assembly process, independently of additional H-bond interactions.
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http://dx.doi.org/10.1039/c6sm01836j | DOI Listing |
Nat Commun
January 2025
School of Materials Science and Chemical Engineering, Institute of Drug Discovery Technology, Institute of Mass Spectrometry, Zhejiang Engineering Research Center of Advanced Mass Spectrometry and Clinical Application, Ningbo University, Ningbo, PR China.
C-C bond cleavage and recombination provide an efficient strategy for the modification and reconstruction of molecule structures. Herein, we present a method for achieving amidation of aryl C(sp)-H bond through the cleavage and recombination of C-C triple bond with the involvement of nitrous acid esters. This method marks the instance of precise and controlled stepwise cleavage of C-C triple bond, offering a fresh perspective for the cleavage of such bonds.
View Article and Find Full Text PDFJ Org Chem
January 2025
State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, PR China.
An efficient hydrogen bond-mediated alcoholysis of primary amides was disclosed using diethyl phosphonate (DEP) as a catalyst. In this process, a wide range of primary amides and alcohols were tested and smoothly transformed to corresponding esters in moderate to good yields. This novel strategy features transition metal-free, broad substrate scope and a hydrogen bond-mediated one-pot pathway.
View Article and Find Full Text PDFBiochemistry
January 2025
Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, United States.
Branch-point syntheses in nonribosomal peptide assembly are rare but useful strategies to generate tripodal peptides with advantageous hexadentate iron-chelating capabilities, as seen in siderophores. However, the chemical logic underlying the peptide branching by nonribosomal peptide synthetase (NRPS) often remains complex and elusive. Here, we review the common strategies for the biosynthesis of branched nonribosomal peptides (NRPs) and present our biochemical investigation on the NRPS-catalyzed assembly of fimsbactin A, a branched mixed-ligand siderophore produced by the human pathogenic strain .
View Article and Find Full Text PDFJ Org Chem
January 2025
College of Chemistry, Zhengzhou University, Zhengzhou 450001, China.
We report the rapid synthesis of primary amides by directly using commercially available ammonia borane (NH·BH), sodium hexamethyldisilazide (NaHMDS), and esters. The success of this protocol relies on NH·BH as the nitrogen source being considerably more convenient and NaHMDS being an excellent proton abstractor but not participating in the nucleophilic addition reaction. The reaction had a wide substrate scope containing bioactive molecules, and most of the substrates were efficiently amidated over 90% yields.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Organic Chemistry, University of Debrecen Egyetem Square 1 Debrecen 4032 Hungary
Domino Knoevenagel-cyclization reactions of styrene substrates, containing an -(-formyl)aryl subunit, were carried out with -substituted 2-cyanoacetamides to prepare tetrahydro-4-pyrano[3,4-]quinolone and hexahydrobenzo[]phenanthridine derivatives by competing IMHDA and IMSDA cyclization, respectively. The diastereoselective IMHDA step with α,β-unsaturated amide, thioamide, ester and ketone subunits as a heterodiene produced condensed chiral tetrahydropyran or thiopyran derivatives, which in the case of Meldrum's acid were reacted further with amine nucleophiles in a multistep domino sequence. In order to simplify the benzene-condensed tricyclic core of the targets and get access to hexahydro-1-pyrano[3,4-]pyridine derivatives, a truncated substrate was reacted with cyclic and acyclic active methylene reagents in diastereoselective Knoevenagel-IMHDA reactions to prepare novel condensed heterocyclic scaffolds.
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