Glycine conjugates of aliphatic carboxylic acids of clinical interest, and a series of structurally related compounds, were synthesized. The gas chromatographic elution behavior of trimethylsilyl derivatives of these N-acylglycines was examined on columns of 5% OV-1. A single peak for each compound was observed on the chromatograms after derivatization with a reagent containing N,9-bis-(trimethylsilyl)-acetamide in pyridine (1 : 1, v/v) for 20 min at 60 degrees C. The methylene unit values of the trimethylsilyl derivatives of these N-acylglycines are reported.
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http://dx.doi.org/10.1016/0009-8981(75)90274-0 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Freie Universität Berlin: Freie Universitat Berlin, Institut für Chemie und Biochemie, GERMANY.
Herein, we present the first easy-to-access synthesis of the perfluorotrityl cation (15F+) with commercial GaCl3 and the further functionalization of the para-fluorine atoms of 15F+ via halodefluorination using trimethylsilyl halides TMSX (X = Cl, Br). This gives access to equally reactive perhalogenated trityl derivatives (p-3Cl12F+ and p-3Br12F+), which can be handled at room temperature. The impact of the para-exchange on the electronic structure is determined by NMR and UV-Vis spectroscopy.
View Article and Find Full Text PDFMolecules
December 2024
Grupo Química-Física Molecular y Modelamiento Computacional (QUIMOL), Escuela de Ciencias Químicas, Universidad Pedagógica y Tecnológica de Colombia, Sede Tunja, Avenida Central del Norte, Boyacá 150003, Colombia.
Silylation is a widely used derivatization technique for the gas chromatographic analysis of benzodiazepines, a class of psychoactive drugs commonly encountered in forensic and biological samples. This study investigated the optimal experimental conditions for the silylation of benzodiazepines using ,-bis(trimethylsilyl)trifluoroacetamide containing 1% trimethylchlorosilane (BSTFA + 1% TMCS), a widely employed silylating agent. Ten structurally different benzodiazepines, including variations within the classic 1,4-benzodiazepine core and triazolo ring derivatives, were selected to address the effect of structural diversity on silylation.
View Article and Find Full Text PDFOrg Lett
January 2025
State Key Laboratory of Chemical Resource Engineering, Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
The cascade reaction of 3-diazo-2-sulfonyliminoindolines and -methoxymethyl--[(trimethylsilyl)methyl]benzylamines generates 2-sulfonylimino-1',3',4',6'-tetrahydro-2'-spiro[indoline-3,5'-pyrimidine] and spiro[indoline-3,3'-pyrrolidine] derivatives simultaneously under the catalysis of TFA and blue light irradiation. Their formation mechanisms were proposed on the basis of isotope-labeled experiments and HRMS analysis of the controlled experiment mixture, showing new reaction pathways. The current reaction provides a new strategy for the synthesis of biologically important spiro[indoline-3,3'-pyrrolidine]-2-one derivatives.
View Article and Find Full Text PDFBeilstein J Org Chem
December 2024
Department of Chemical and Geological Sciences, University of Cagliari, S.S. 554, bivio per Sestu, 09042 Monserrato (CA), Italy.
The rising popularity of bioconjugate therapeutics has led to growing interest in late-stage functionalization (LSF) of peptide scaffolds. α,β-Unsaturated amino acids like dehydroalanine (Dha) derivatives have emerged as particularly useful structures, as the electron-deficient olefin moiety can engage in late-stage functionalization reactions, like a Giese-type reaction. Cheap and widely available building blocks like organohalides can be converted into alkyl radicals by means of photoinduced silane-mediated halogen-atom transfer (XAT) to offer a mild and straightforward methodology of alkylation.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
December 2024
Faculty of Pharmacy, Osaka Ohtani University.
We have investigated the base-induced long-range halogen dance reactions of 4,5-dibromo- or 4-bromo-5-iodothiazoles bearing sulfur-containing aromatic heterocycles at the C2-position. We have found that the reaction occurs in bithiazole regioisomers or (thiophenyl)thiazole derivatives, in which the C-5 halo group on the thiazole halogen donor regioselectively migrates to a halogen acceptor ring after treatment with lithium bis(trimethylsilyl)amide. The substrate with a thiophen-2-yl substituent required highly basic P
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