Conformationally flexible hexakis-urea 1 was synthesized efficiently by condensing hexakis(aminomethyl)benzene with 4-nitrophenyl-(3,5-di-tert-butylphenyl)carbamate. The hexakis-urea 1 is unexpectedly soluble in organic solvents of low polarity due to intramolecular hydrogen bonding. The hexakis-urea 1 recognizes chloride, bromide, and acetate in a 1:2 host-guest ratio and in a positive allosteric manner in CDCl . The ability of 1 to recognize dihydrogen phosphate is a unique outcome, and the structure of the associated complex, which contains four dihydrogen phosphate ions, was clarified by single-crystal X-ray structural analysis. However, in solution, a complex with three dihydrogen phosphate ions was identified. The dihydrogen phosphate association in CDCl proceeds in an amphoteric allosteric manner; in a positive allosteric manner (K
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Sci Rep
January 2025
Pharmaceutical Chemistry Department, Faculty of Pharmacy, Horus University, New Damietta, 34517, Egypt.
RP-HPLC technique was developed and optimized for simultaneous identification and estimation of nirmatrelvir (NIR) and ritonavir (RIT) in their new copackaged tablet. Stability of nirmatrelvir (NIR) was studied after exposure to different five stress conditions; alkali, acid, heat, photo and oxidation degradation. The chromatographic separation was achieved using VDSpher PUR 100 ODS (4.
View Article and Find Full Text PDFLuminescence
January 2025
Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Tanta University, Tanta, Egypt.
Based on nitrogen and phosphorus co-doped carbon dots (NP-CDs), a direct, quick, and selective sensing probe for fluorometric detection of rutin has been developed. Utilizing ethylene diamine tetra acetic acid (EDTA) as a carbon and nitrogen source and diammonium hydrogen phosphate (NH)HPO as a nitrogen and phosphorus source. The NP-CDs were synthesized in less than 3 min with a straightforward one-step microwave pyrolysis process with a high quantum yield (63.
View Article and Find Full Text PDFSci China Life Sci
January 2025
CAS Engineering Laboratory for Nanozyme, Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
Alternative treatment for the highly prevalent Helicobacter pylori infection is imperative due to rising antibiotic resistance. We unexpectedly discovered that the anti-H. pylori component in garlic is hydrogen polysulfide (HS, n⩾2), not organic polysulfides.
View Article and Find Full Text PDFNat Chem Biol
January 2025
Department of Gastroenterology, Hubei Clinical Center and Key Laboratory of Intestinal and Colorectal Disease, TaiKang Center for Life and Medical Sciences, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China.
In prokaryotes, the non-bridging oxygen in the DNA sugar-phosphate backbone can be enzymatically replaced by a sulfur atom, resulting in phosphorothioate (PT) modification. However, the mechanism underlying the oxygen-to-sulfur substitution remains enigmatic. In this study, we discovered a hypercompact DNA phosphorothioation system, TdpABC, in extreme thermophiles.
View Article and Find Full Text PDFJ Prosthet Dent
January 2025
Associate Professor, Department of Prosthodontics, Dental Branch, Islamic Azad University of Medical Sciences, Tehran, Iran.
Statement Of Problem: The optimal zirconia pretreatment, contingent upon the type of cement used, warrants further research.
Purpose: The purpose of this investigation was to evaluate the influence of various surface pretreatments on the bonding efficacy of cement to zirconia.
Material And Methods: A comprehensive search was conducted across the PubMed, Embase, Scopus, and Web of Science databases for in vitro studies related to bonding with zirconia up to April 2024, supplemented by a manual search.
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