10.1021/ol702392x
The research focuses on the direct and versatile synthesis of rare nucleotide furanoses, specifically uridine 5'-diphosphofuranoses, from unprotected thioimidoyl furanosides. The study explores the diastereoselectivity of the reaction, influenced by factors such as reaction time, temperature, and the nature of the furanosyl donor. The experiments involved the use of thioimidates as efficient glycosylation donors and the acidic form of UDP (uridine 5'-diphosphate) as an acceptor, aiming to avoid the need for chemical activation. The reactants included various benzimidazolyl furanosides and UDP disodium salt dihydrate. The analysis was conducted using 31P NMR to monitor the phosphorylation reaction and assess the diastereoselectivity. The study also employed reverse-phase HPLC to separate and characterize the synthesized nucleotide furanoses, including the identification of anomers. The innovative aspect of this research is the one-step synthesis method that does not result in ring expansion to pyranose forms or the formation of UMP-furanoses, suggesting a potential approach closer to chemoenzymatic synthesis.
10.1016/j.tetlet.2008.11.123
The research focuses on the development of a novel three-component reaction for the synthesis of N-cyclohexyl-3-aryl-quinoxaline-2-amines, which are nitrogen-containing heterocyclic compounds with significant biological activity and applications in drug discovery and various chemical industries. The study utilizes a three-component condensation reaction catalyzed by ferric perchlorate, involving o-phenylenediamine, aromatic aldehydes, and cyclohexyl isocyanide, to produce the desired quinoxaline derivatives in good yields. The experiments were conducted by refluxing a mixture of the three reactants in acetonitrile with a catalytic amount of ferric perchlorate for 2 hours. The progress of the reactions was monitored by thin-layer chromatography (TLC), and the products were obtained without further purification after the reaction mixture was diluted, separated, and dried. The synthesized compounds were characterized using melting point determination, infrared spectroscopy (IR), proton and carbon nuclear magnetic resonance (1H NMR and 13C NMR), gas chromatography-mass spectrometry (GC/MS), and elemental analysis, which confirmed their structures and composition.
10.1021/jf902863z
The research focuses on the synthesis and biological evaluation of 4-methyl-1,2,3-thiadiazole derivatives, which are potential candidates for novel pesticides with diverse biological activities. The study employs the Ugi four-component condensation reaction (U-4CR), a green and rapid one-pot process, to synthesize two series of these derivatives, incorporating active substructures of 3-chloro-4-methylphenyl or 3-fluoro-4-methylphenyl. The reactants used in the Ugi reaction include amines, carbonyl compounds (aldehydes or ketones), isocyanides, and carboxylic acids, with specific mention of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid, cyclohexyl isocyanide, and various substituted benzaldehyde derivatives. The synthesized compounds were characterized using proton nuclear magnetic resonance (1H NMR) and high-resolution mass spectrometry (HRMS). The biological activities of the target compounds, including fungicide activity, antivirus activity in vitro and in vivo, and systemic acquired resistance, were systematically evaluated. The experiments involved the use of different fungi strains for fungicide screening and tobacco plants for antivirus and systemic acquired resistance assessments. The results indicated that certain derivatives showed potential broad-spectrum fungicidal activity and direct antivirus activities against tobacco mosaic virus (TMV), with the structure-activity relationship suggesting that the presence of specific substituents on the phenyl rings influenced the biological activities.