10.1016/j.tet.2007.11.036
The study presents a two-step synthesis method for benzo-fused 2,8-dioxabicyclo[3.3.1]nonane derivatives, utilizing a domino Knoevenagel condensation/intramolecular hetero-Diels-Alder reaction sequence. The process involves an initial intermolecular Knoevenagel condensation of a compound with active methylene compounds to form a heterodiene, which then undergoes intramolecular hetero-Diels-Alder cycloaddition. The research successfully optimized the reaction conditions, including the choice of catalyst and solvent, to achieve high yields of the desired products. The method demonstrates a novel route for constructing complex heterocycles with potential applications in medicinal chemistry.
10.1021/acs.jnatprod.0c00250
The research focuses on the isolation and characterization of three new linear peptides, iheyamides A, B, and C, derived from a marine Dapis sp. cyanobacterium collected off Noho Island in Okinawa, Japan. The study utilized spectroscopic analyses and degradation reactions to elucidate their structures, which were confirmed by NMR data, HRESIMS, and 2D NMR techniques. The research also assessed the antitrypanosomal activities of these peptides against Trypanosoma brucei rhodesiense and Trypanosoma brucei brucei, as well as their cytotoxicity against normal human WI-38 cells. The experiments involved extraction with EtOH, partitioning between EtOAc and H2O, followed by further purification using reversed-phase column chromatography and HPLC. The absolute configurations of the amino acids were determined through acid hydrolysis, chiral-phase HPLC analyses, and ozonolysis. The results showed that iheyamide A exhibited moderate antitrypanosomal activity with an IC50 of 1.5 μM and significantly lower cytotoxicity against normal human cells (IC50 = 18 μM), highlighting its potential as a lead compound for developing new antitrypanosomal drugs.
10.1039/jr9510002064
The study investigates methods for synthesizing and analyzing the reactions of branched-chain hydrocarbons with a regular pattern of quaternary carbon atoms. Key chemicals involved include 1-chloro-3:5:5-trimethylhexane, which is used to prepare Grignard compounds essential for further reactions. The study describes the synthesis of complex hydrocarbons such as 2:2:4:7:10:12:12-heptamethyltridecan-7-ol and 2:2:4:10:12:12-hexamethyl-7-(3:5:5-trimethylhexyl)tridecan-7-ol through reactions involving esters like ethyl acetate. These alcohols are then dehydrated to form olefins, whose structures are confirmed via ozonolysis. Other chemicals like silver bromide are used to produce 2:2:4:9:11:11-hexamethyldodecane. The study aims to explore the potential and limitations of using alkylmagnesium halides in synthesizing these hydrocarbons, providing detailed experimental procedures and characterizations of the synthesized compounds.
10.3390/molecules21111443
The study focuses on the characterization of the O-methyltransferase enzyme JerF, which is involved in the late stages of jerangolid biosynthesis. JerF is unique for its ability to catalyze the formation of a non-aromatic, cyclic methylenolether, a reaction not previously characterized in other O-methyltransferases. The researchers successfully overexpressed JerF in E. coli and utilized cell-free extracts to conduct bioconversion experiments. They also chemically synthesized a range of substrate surrogates to evaluate JerF's catalytic activity and substrate tolerance. The results revealed that JerF has a broad substrate tolerance and high regioselectivity, making it a promising candidate for chemoenzymatic synthesis, particularly for the modification of natural products containing a 4-methoxy-5,6-dihydro-2H-pyran-2-one moiety. The study also highlighted the potential of JerF in introducing specific methylation patterns and its use in biorthogonal coupling reactions, such as click chemistry, for site-specific labeling of biomolecules like DNA, RNA, or proteins.
10.1016/j.bmc.2015.05.026
The study focuses on the synthesis, molecular docking, and biological evaluation of 3-Arylfuran-2(5H)-ones as potential anti-gastric ulcer agents. The researchers synthesized twenty derivatives of 3-Arylfuran-2(5H)-ones and assessed their anti-Helicobacter pylori (anti-H. pylori), antioxidant, and urease inhibitory activities, which are crucial for combating H. pylori infections linked to gastritis and peptic ulcers. The results indicated that several compounds showed notable antioxidant and anti-H. pylori activities, with compound b9, 3-(3-methylphenyl)furan-2(5H)-one, demonstrating the most potent antioxidant activity and good anti-H. pylori activity, suggesting its potential as a novel anti-gastric ulcer agent. Additionally, the study explored the compounds' interactions with tyrosyl-tRNA synthetase (TyrRS) through molecular docking, providing insights into their mechanism of action.
10.1007/s10593-007-0106-x
The research article from "Chemistry of Heterocyclic Compounds" discusses an unexpected outcome from the interaction of 1,8-diaminonaphthalene with aromatic nitriles in polyphosphoric acid (PPA). The researchers initially expected the formation of 2-Ar-perimidines or their acylated products but instead discovered the formation of previously unknown 2,6,8-triaryl-1,3,7-triazapyrenes. The reaction mechanism is proposed to involve the formation of a 2-Ar-perimidine, followed by electrophilic attack by the nitrile cation, cyclization, and aromatization via ammonia elimination. The general method involved mixing 1,8-diaminonaphthalene, an aromatic nitrile, and PPA, stirring at 180°C, then cooling, adding water, basifying with ammonia, and extracting with ethyl acetate. The products were characterized using 1H NMR spectroscopy, and their yields and melting points were reported. The study also included elemental analysis to confirm the composition of the synthesized compounds.
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