A general procedure for the synthesis of amides via the direct condensation of carboxylic acids and amines in the presence of TiCl is reported. The amidation reaction was performed in pyridine at 85 °C with a wide range of substrates providing the corresponding amide products in moderate to excellent yields and high purity. The reaction proceeds with low yields when both the carboxylic acid and the amine are sterically hindered. The process takes place with nearly complete preservation of the stereochemical integrity of chiral substrates.
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http://dx.doi.org/10.1186/s13065-017-0318-9 | DOI Listing |
bioRxiv
December 2024
Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire, UK.
Conjugation, the major driver of the spread of antimicrobial resistance genes, relies on a conjugation pilus for DNA transfer. Conjugative pili, such as the F-pilus, are dynamic tubular structures, composed of a polymerized pilin, that mediate the initial donor-recipient interactions, a process known as mating pair formation (MPF). IncH are low-copy-number plasmids, traditionally considered broad host range, which are found in bacteria infecting both humans and animals.
View Article and Find Full Text PDFChem Sci
December 2024
College of Science, Engineering and Environment, University of Newcastle Callaghan NSW 2308 Australia.
The inductive effect is a central concept in chemistry and is often exemplified by the p values of acetic acid derivatives. The reduction in p is canonically attributed to the reduction in the electron density of the carboxylate group through the inductive effect. However, wave functional theory calculations presented herein reveal that the charge density of the carboxylate group is not explained by the inductive effect.
View Article and Find Full Text PDFMolecules
December 2024
Centro per la Conservazione ed il Restauro dei Beni Culturali "La Venaria Reale", Via XX Settembre 18, 10078 Venaria Reale, Turin, Italy.
The formation of metal soaps or carboxylates in oil paintings is a widely studied topic. Expanding upon the extant research on the subject, this work investigates the formation of metal soaps as pertaining to alkyd-based media. Especially popular in modern and contemporary art, alkyd paints are complex commercial formulations mainly containing a polyester backbone obtained by the condensation of glycerol and phthalic acids, where the third free alcoholic function is esterified with a blend of saturated and unsaturated fatty acids.
View Article and Find Full Text PDFChemistryOpen
January 2025
Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Department of Chemistry, Ciudad Autónoma de Buenos Aires, 1113, Argentina.
Gem-diols are defined as organic molecules carrying two hydroxyl groups at the same carbon atom, which is the result of the nucleophilic addition of water to a carbonyl group. In this work, the generation of the hydrated or hemiacetal forms using pyridine- and imidazole-carboxaldehyde isomers in different chemical environments was studied by Nuclear Magnetic Resonance (NMR) recorded in different media and combined with theoretical calculations. The change in the position of aldehyde group in either the pyridine or the imidazole ring had a clear effect in the course of the hydration/hemiacetal generation reaction, which was favored in protic solvents mainly in the presence of methanol.
View Article and Find Full Text PDFJ Biomol Struct Dyn
January 2025
Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
Four organotin(IV) carboxylate complexes; (CH)SnL (), CHSnL (), (CH)SnL () and (CH)SnL () are synthesized by the condensation reaction of organotin(IV) chlorides with sodium-4-chloro-2-methylphenoxyacetate (). The FT-IR spectra suggested bridging/chelating bidentate coordination of the ligand to the tin atom. Single-crystal XRD analysis authenticated the FT-IR findings for and .
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