10.1016/S0022-328X(00)96083-2
The study explores the application of free radicals in the catalytic synthesis of carbon monoxide derivatives, focusing on the reaction of carbon monoxide with organomagnesium compounds in the presence of various carbonyl compounds in tetrahydrofuran. The main product of these reactions was tetrahydrofuranyl-2-ethyl ketone, suggesting a radical mechanism. The reactions were found to be complex, yielding over ten products, including ketones, tertiary alcohols, and hydrocarbons. The study also discusses the potential for other radical sources to facilitate similar reactions, opening new avenues for organic synthesis.
10.1016/S0022-328X(98)01075-4
The study in the Journal of Organometallic Chemistry focuses on the synthesis and characterization of transition metal complexes derived from heterocyclic compounds, specifically 2,3-dihydro-1,3-azaphospholo[5,1-b]thiazole and -oxazole. The researchers reacted these heterocyclic compounds with [(THF)M(CO)5]2 (where M represents chromium, molybdenum, or tungsten) to selectively form (η1-P)-(2,3-dihydro-1,3-azaphospholo[5,1-b]thiazole and -oxazole)M(CO)5 complexes. The complexes were characterized using NMR spectroscopy, and the results were compared with those of the free ligands. The study also discusses the preference for η1-P coordination over other possible coordination modes, attributing this to the influence of d(M)→π* back-bonding. The research provides insights into the chemical properties of these heteroaromatic compounds and their potential applications in organometallic chemistry.
10.1248/cpb.56.1486
The research focuses on the synthesis and evaluation of 1,2-dihydro-2l5-[1,2,4]triazolo[4,3-d][1,3,4,2]thiadiaza-phosphol-2-one derivatives, which are reported to possess a broad spectrum of biological activities, including antioxidant and antibacterial properties. The synthesis involved the condensation of phosphonic dichlorides, substituted phosphorodichloridates, and bis(2-chloroethyl)amine dichloride with 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol in the presence of a base in dry tetrahydrofuran (THF). The synthesized compounds were characterized using IR, 1H-, 13C-, and 31P-NMR spectroscopy, as well as mass spectrometry. The antioxidant activity of these compounds was assessed using three methodologies: 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging, lipid peroxidation, and hydroxyl radical scavenging assays. The antibacterial activity was tested using the agar well bioassay and minimum inhibitory concentration (MIC) determination. The results indicated that some of the synthesized compounds showed significant antioxidant and antimicrobial activities, warranting further in vivo studies for potential therapeutic applications.
10.1007/BF00764628
The study focuses on the synthesis and biological activity of the trimethylsilyl ether of Vitamin D2, a compound of interest due to its potential to increase the stability of antirachitic preparations. The researchers synthesized Vitamin D2 trimethylsilyl ether (I) using a reaction involving hexamethyldisilazane and trimethylsilyl chloride, and then assessed its biological activity through various tests including calcium and phosphorus levels in blood, alkaline phosphatase activity, and the presence of a specific calcium-binding protein in the duodenal mucosa of Leghorn chicks. The results showed that the biological activity of the etherified Vitamin D2 was comparable to the non-etherified form, with some differences attributed to molecular mass and equimolar amounts. The study also examined the stability of the preparation over a six-month storage period, finding that the etherified form demonstrated greater stability, which was hypothesized to be due to the protective effects of the trimethylsilyl group against oxidation and degradation. The findings suggest that the use of silylated derivatives could reduce the loss of Vitamin D2 during storage, thereby increasing its economic value.
10.1016/j.jorganchem.2008.04.006
The study focuses on the synthesis, characterization, and reactivity of rhodium(III) complexes with N-boranyl-1,3,5-triaza-7-phosphaadamantane (N–B–PTA(BH3)) ligands. The reaction of N–B–PTA(BH3) with [CpRhCl(l-Cl)]2 yields complexes [CpRh{N–B–PTA(BH3)}Cl2] (3) or [CpRh{N–B–PTA(BH3)}2Cl]Cl (5), containing one or two P-bonded boronated PTA ligands. The hydride [CpRh{N–B–PTA(BH3)}H2] (8) was also obtained by reaction with NaBH4. These complexes can undergo hydrolysis to produce dihydrogen and H3BO3, along with PTA derivatives. Furthermore, the reaction of complex 8 with electron-poor alkynes results in the formation of alkene complexes [Cp*Rh{N–B–PTA(BH3)}(g2-CH2 = CHR)] without affecting the N–BH3 moiety. The X-ray crystal structures of complexes 3 and 10 were determined and discussed, providing insights into the coordination chemistry and potential applications of these water-soluble rhodium complexes.
10.1016/S0040-4039(01)00868-1
The study focuses on the 1,2-Wittig rearrangement of chiral β-alkoxycarboxamides to synthesize optically active aldol derivatives. The research explores how treating chiral β-benzyloxy- or β-propargyloxycarboxamides with tert-butyllithium leads to the formation of β-hydroxycarboxamides through the 1,2-Wittig rearrangement, while maintaining high optical purity and chirality transfer. The study highlights the significance of this reaction for the synthesis of optically active compounds, which are valuable intermediates in organic synthesis, particularly for creating complex natural products.
10.1039/c3dt51497h
The study focuses on the formation and structural characterization of a five-membered zirconacycloallenoid, a type of metallocene complex, through the reaction of a conjugated enyne with in situ generated zirconocene. The resulting compound was thoroughly analyzed using X-ray diffraction, revealing its unique structure and bonding characteristics. The research also explored the compound's reactivity, demonstrating its distinct behavior in reactions with additional zirconocene and acetonitrile, leading to the formation of different complexes. This work not only provides detailed insights into the structure and properties of metallacycloallenoid complexes but also uncovers new chemical reactions and potential applications in organometallic chemistry.
10.1021/om700746h
The research study on the influence of the anion of salts used on the coordination mode of an N-heterocyclic carbene (NHC) ligand to osmium. The purpose of the study was to understand the factors determining the formation of less favored tautomers and their influence on the behavior of other coligands in transition-metal complexes, which is crucial for understanding mechanisms and products in both biological and catalytic processes. The researchers reacted the hexahydride OsH6(PiPr3)2 with 1.0 equivalent of BPh4-, BF4-, and Br- salts of 1-(2-pyridylmethyl)-3-methylimidazolium in tetrahydrofuran under reflux, resulting in mixtures of abnormal and normal isomers. They observed that the formation rate of the abnormal isomer and the abnormal to normal ratio decreased with increasing coordinating power of the anion. The study concluded that both the rates of organometallic reactions and the stability of the formed products are significantly dependent on the nature of the anions used in the salts, with the anion's coordinating power affecting the isomer ratio and stability. The research provides valuable insights into the role of anions in organometallic chemistry and could have implications for the design of new catalytic systems.
10.1080/00397919608003872
The study investigates a new method for synthesizing diaryldisulfides. The key chemicals involved are arylsulfonyl chlorides and sodium arylsulfinates, which serve as the starting materials. These compounds are reduced to the corresponding diaryldisulfides using a TiCl4/Sm system in tetrahydrofuran (THF) at 60°C. The TiCl4/Sm system acts as a reducing agent, facilitating the conversion of the higher oxidation state sulfur compounds (arylsulfonyl chlorides and sodium arylsulfinates) into the lower oxidation state diaryldisulfides. The study reports moderate to good yields of the desired products, highlighting the method's potential as an attractive alternative for diaryldisulfide synthesis due to its simple procedure, neutral conditions, and the availability of starting materials.
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