10.1007/s00706-007-0649-7
The research focuses on the synthesis of novel heterocyclic compounds, specifically 1,2,4-triazol-3-ylmethyl-, 1,3,4-oxa-, and -thiadiazol-2-ylmethyl-1H-[1,2,3]-triazolo[4,5-d]pyrimidinediones, which are potentially useful as antiviral agents against hepatitis B virus. The experiments involved the synthesis of 1-carbethoxymethyl-4,6-dimethyl-1H-[1,2,3]triazolo[4,5-d]pyrimidine-5,7(4H,6H)-dione and its subsequent reactions with hydrazine hydrate to yield a hydrazide. This hydrazide was further reacted with phenylisothiocyanate or carbon disulfide and KOH to produce thiosemicarbazide and oxadiazole derivatives. Various alkylation and cyclization reactions were performed to form the desired heterocyclic structures, including the formation of 1,3,4-thiadiazole, 5-mercapto-1,2,4-triazole, and 1,3,4-oxadiazole rings. The synthesized compounds were analyzed using techniques such as infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry (MS) to confirm their structures. The reactants used in these syntheses included phenylisothiocyanate, carbon disulfide, alcoholic potassium hydroxide, dimethyl sulfate, ethyl chloroacetate, and various monosaccharide aldoses. The synthesized compounds were tested for their antiviral activity, with some showing moderate activities against hepatitis B virus.
10.1016/S0040-4020(01)00801-8
The study focuses on the synthesis of functionalized tetradentate ligands for use in Ru-sensitized solar cells, aiming to improve light absorption and prevent cis-isomerization. Key chemicals used include 6,6'-bis(1-H-benzimidazol-2-yl)-4,4'-bis(methoxycarbonyl)-2,2'-bipyridine and a series of new quaterpyridines as tetradentate ligands, along with various reagents such as peracetic acid, dimethyl sulfate, potassium cyanide, and o-phenylenediamine dihydrochloride. These chemicals serve to construct and modify the ligands through a series of reactions, with the goal of creating stable trans-complexes that enhance the efficiency of solar cells by shifting the lowest energy MLCT band and improving light absorption.
10.1016/0223-5234(92)90148-T
The research focuses on the synthesis and antihepatotoxicity evaluation of Wuweizisu analogues. The purpose of the study is to develop new liver-protective agents by synthesizing and testing the efficacy of certain chemical compounds derived from Schisandra sinensis (Wuweizi), a traditional Chinese medicine known for its various pharmacological properties, especially its antihepatotoxic effects. The researchers synthesized a series of compounds, including dimethyl 4,4’-dimethoxy-5,6,5’,6’-dimethylenedioxybiphenyl-2,2’-dicarboxylate (VII) and 6-phenyl-3,9-dimethoxy-1,2-methylenedioxy-10,11-methylenedioxy-6,7-dihydro-5H-dibenz(c,e)azepin (X), using key chemicals such as gallic acid, dimethyl sulfate, bromine, aniline, and lithium aluminum hydride. The synthesized compounds were tested for their ability to protect against carbon tetrachloride-induced liver damage in primary cultured rat hepatocytes. The results showed that compound X exhibited superior antihepatotoxic activity compared to the known protective agents DDB and silymarin. This suggests that the synthesized compounds, particularly those with a dibenzoazepin structure, could serve as potential new liver-protective agents, offering a novel route for the development of such pharmaceuticals.
10.1016/S0040-4039(00)94183-2
The research investigates the dithiolation mechanism in the reactions of polyhaloarenes as di-aryne equivalents. The purpose is to understand how different substituents on polyhaloarenes influence the reaction pathways when treated with organolithium reagents. The key chemicals used include 1,2,4,5-tetrabromobenzenes, furan, organolithium reagents like n-BuLi, and various electrophiles such as methanol, iodine, and (CH3)2SO4. The study concludes that the reaction mechanism can proceed via either a monolithio intermediate (Path A) or a dilithio intermediate (Path B), depending on the nature of the substituents. Specifically, when the substituent is an electron-withdrawing group like chlorine, the reaction proceeds via Path B, forming a stable dilithio intermediate. This intermediate is stable at low temperatures but eliminates lithium bromide at higher temperatures to form arynes. The findings suggest that the para orientation of lithium atoms in these dilithio compounds is due to the minimization of repulsion between negative charges. The results have implications for the synthesis of complex aromatic compounds like anthracenes and phenanthrenes from readily available precursors.
10.1080/00397919108021779
The study presents a method for the synthesis of substituted N-monoalkylaromatic amines under phase-transfer catalysis (PTC) conditions. The researchers used various aromatic amides and amines as starting materials, which were converted to N-monoalkylated products using dimethyl sulphate as the alkylating agent. The reaction was facilitated by the presence of powdered sodium hydroxide, potassium carbonate, and tetrabutylammonium hydrogen sulphate as the PTC. The study found that compounds with ortho electron-withdrawing substituents exclusively yielded monoalkyl amines, while those with electron-donating substituents or no substituents resulted in alkyl amides. The researchers proposed a mechanism for the alkylation and deacylation processes and verified it experimentally. The study provides a simple, economical one-pot synthesis method for producing ortho substituted aromatic monoalkyl amines with electron-withdrawing substituents.
10.1134/S1070428006080173
This study investigates the synthesis of meta-terphenyl derivatives through the recyclization of nitropyridinium quaternary salts. The researchers employed a two-component Hantzsch synthesis to create unsymmetrical nitropyridines (IVa-IVf) from nitrochalcones and various enamines, which were then converted into nitropyridinium salts (Va-Vf) via alkylation with dimethyl sulfate. The key step involved treating these salts with aqueous-alcoholic alkali, leading to the formation of 5'-methylamino-2'-nitro-m-terphenyl derivatives (Vla-VIf) through a series of reactions including hydroxy anion attacks, isomerization, and intramolecular aldol-crotonic condensation. The study also explored the recyclization of salts with different substituents, resulting in various m-terphenyls with different functional groups such as carboxyl, methyl ester, and ethyl ester groups. The newly synthesized compounds were characterized by elemental analysis, IR, 1H NMR, and mass spectra, confirming their structures and compositions.
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