10.1007/s10593-010-0647-2
The study focuses on the intramolecular cyclization of 1-[1-alkylsulfanyl-2-phenyl-2-(phenylhydrazono)ethylidene]pyrrolidinium salts, which are synthesized by the alkylation of thioamide with benzyl, allyl, and propargylsulfanyl groups in the presence of cesium carbonate in DMF at room temperature. These pyrrolidinium salts can be efficiently converted into 1,3-diphenyl-6,7,8,8a-tetrahydro-1H-pyrrolo[2,1-c]-1,2,4-triazine-4-thione derivatives in good yields. The research demonstrates that this cyclization method is general for alkyl derivatives of arylhydrazonothioacetamides, expanding the scope of this reaction type. The synthesized pyrrolotriazines are of practical interest due to their potential high antitumor activity, making them promising candidates for biological investigation. The study was financially supported by the Russian Basic Research Fund and includes detailed experimental procedures, characterization data, and comparison of the reaction outcomes with different bases and solvents.
10.1016/j.tet.2008.05.040
The study focuses on the synthesis and characterization of branched supramolecular polymers derived from bifunctional cyclodextrin (CD) derivatives. The researchers prepared these polymers by mixing 3-cinnamamide-α-CD (1) with 3-Na-cinnamamidehexancarbonyl-N3-cinnamamide-lysinamide-α-CD (3) and 3-cinnamamidehexanamide-α-CD (2) with 3. The study revealed that compounds 1 and 2 formed linear supramolecular polymers, while compound 3, featuring two guest moieties, resulted in hyperbranched supramolecular polymers. The physical properties of these polymers were examined through viscosity measurements in aqueous solutions, showing that the introduction of compound 3 as a branching unit significantly increased the viscosity. The supramolecular polymers did not exhibit a viscosity increase on their own, but their mixtures formed highly viscous solutions and fibers, attributed to branching of linear supramolecular polymers by compound 3 and interactions such as hydrophobic and hydrogen bonding between the polymers. The research provides insights into the formation and properties of supramolecular polymers with potential applications in material science.
10.1016/j.tetlet.2012.07.093
The study describes a new and efficient method for synthesizing indolo[3,2,1-jk]carbazoles through palladium-catalyzed intramolecular cyclization of N-(2-bromoaryl)carbazoles. The reaction involves forming carbon-carbon bonds via intramolecular arylation, which proceeds with the cleavage of C–X and C–H bonds on the carbazole ring. Various substituted N-aryl carbazole substrates, containing both electron-donating and electron-withdrawing groups, were explored under optimized conditions. The study successfully yielded indolo[3,2,1-jk]carbazoles with high thermostability, good fluorescence properties, and electron-donor potential, making them promising candidates for applications in organic electronics and material chemistry.
10.1071/CH16710
The study reports on the successful synthesis and characterization of two 28-membered, 2,2'-bipyridine-containing macrocycles in high yield. The first macrocycle was formed through a Williamson ether synthesis, and upon reduction with sodium borohydride, the second macrocycle was produced quantitatively. These macrocycles, which contain a 2,2'-bipyridine unit, are potentially useful components for creating a variety of interlocked architectures, including catenanes, rotaxanes, and molecular machines. The research builds upon previous work by Sauvage, Stoddart, and Feringa, who were awarded the 2016 Nobel Prize in Chemistry for their contributions to the design and synthesis of molecular machines, and it aims to improve upon the yield-limiting macrocyclisation reactions that have historically been a challenge in the field. The study also discusses the use of high-yielding synthetic strategies and the potential for future investigations into the metal-complexation properties of these ligands and their application in forming interlocked structures.
10.1002/ejoc.200400213
The research focuses on the synthesis of a small library of highly electron-rich 2-aryl and 2-heteroaryl phenethylamines (PEAs) using the Suzuki-Miyaura cross-coupling reaction, which is enhanced by microwave irradiation for improved reaction yield and speed. The study commenced with the synthesis of benzyl [2-(2-bromo-4,5-dimethoxyphenyl)ethyl]carbamate from 2-(3,4-dimethoxyphenyl)ethylamine, followed by its coupling with various boronic acids to generate the PEAs. The reactions were optimized using sodium hydrogencarbonate as the base and tetrakis(triphenylphosphane)palladium(0) as the catalyst, with the mixture of N,N-dimethylformamide and water as the solvent. The synthesized compounds were characterized by 1H and 13C NMR spectroscopy, and low-resolution mass spectrometry (LR-MS) to confirm their structures and purities. The research also successfully extended this methodology to synthesize an apogalanthamine analogue, a complex natural product with significant biological activities, showcasing the versatility and efficacy of the developed synthetic strategy.
10.1021/ol026383i
The research focuses on the synthesis of dimethylaminomethylene vinamidinium salts, which are significant synthetic intermediates, through a [2 + 2] cycloaddition route starting from γ-fluoroalkanoic acids. The primary reactants include trifluoropropanoic acid, phosphorus oxychloride (POCl3), and N,N-dimethylformamide (DMF). The reaction pathway involves the formation of an intermediate trifluoromethyl enamine, which can either react with additional POCl3 to form a vinamidinium salt or undergo a thermally driven loss of fluoride to generate an iminium ion, leading to the target product. Spectroscopic studies, including in situ IR and Raman spectroscopy, as well as 31P and 19F NMR spectroscopy, were employed to define the reaction pathway and to construct a mechanistic framework involving two cycloaddition processes. These analyses helped in understanding the reaction mechanism and the factors responsible for the formal loss of the trifluoromethyl group, ultimately providing direct access to these important vinamidiniums and identifying an unusual reactivity mode for γ-fluoroenamines.
10.1080/00397919308011121
The study presents a practical and convenient two-step synthesis of the title compound, 4,6-dichloro-5-benzylthiopyrimidine (3), starting from 4,6-dihydroxypyrimidine (1). The initial three-step approach involved converting 4,6-dihydroxypyrimidine (1) to 4,6-dihydroxy-5-bromopyrimidine (4) with an 80% yield. Then, compound (4) was reacted with benzylmercaptan and anhydrous potassium carbonate in N,N-dimethylformamide, yielding 4,6-dihydroxy-5-benzylthiopyrimidine (2) with a variable yield, the best being 50%. Finally, compound (2) was converted to the title compound (3) by heating in phosphorus oxychloride, resulting in a 75% yield. An improved method was developed using sulfenyl chloride chemistry, where benzyl sulfenyl chloride was prepared from dibenzyl disulfide and sulfuryl chloride, and reacted with 4,6-dihydroxypyrimidine (1) in N,N-dimethylformamide to obtain compound (2) in quantitative yield. The title compound (3) was then synthesized from compound (2) using phosphorus oxychloride, achieving an overall yield of approximately 72%. The study provides a more efficient and reliable synthesis route for 4,6-dichloro-5-benzylthiopyrimidine, which is a key precursor in the synthesis of various types of 4,6-di-substituted pyrimidine-5-sulfonamides with interesting biological activities.
10.1021/ol100387h
The study explores a one-pot procedure for transforming arynes into ortho-disubstituted arenes using formamides and dialkylzincs. Arynes, being highly strained and unstable intermediates, are utilized as electrophiles in this organic synthesis. Formamides, specifically N,N-dimethylformamide (DMF), serve as the carbonyl compounds that react with arynes, facilitating the insertion into the carbonyl group. Dialkylzincs, such as Et2Zn, Me2Zn, and Ph2Zn, act as organometallic reagents to trap the intermediates generated from the insertion process, leading to the formation of ortho-disubstituted arenes. The study investigates various conditions, including different fluoride ion sources and solvents, to optimize the reaction yield and regioselectivity. The results show that the sequential reaction proceeds smoothly via the trapping of quinone methide intermediates derived from the formal [2 + 2] cycloaddition adducts, with high chemical efficiency and regioselectivity under optimized conditions.
10.1021/jo01347a030
The study explores the conversion of L-p-chloroalanine peptides to L-cysteine peptides using thio reagents such as thioacetate, thiobenzoate, and benzyl mercaptide in solvents like N,N-dimethylformamide or ethyl acetate. The researchers synthesized several di-, tri-, and penta-1-cysteine peptides through this method. The study also investigates the reaction of thio reagents with L-p-chloroalanine peptides, resulting in the formation of optically active L-cysteine peptides. The displacement of p-chloro groups by thioacetic acid was extended to peptides with the chloroalanine moiety between other amino acid residues in tripeptides and pentapeptides. The study provides detailed experimental procedures and analytical data for the synthesized compounds.
10.1039/d1gc02002a
The research focuses on developing hypercrosslinked polymers (HCPs) containing dimethylformamide (DMF) moieties as alternatives to DMF solvent for azide-based synthesis. The study synthesized HCP-DMF and HCP-DMF-SO3H, which have flexible DMF-like moieties that provide a polar microenvironment for catalysis. The research aimed to replace hazardous DMF solvent with ethanol (EtOH) in the synthesis of benzylic azides and 1,2,3-triazoles, common structures in bioactive molecules. The experiments involved the conversion of NaN3 to benzylic azides and the synthesis of 1,2,3-triazoles using these HCP catalysts in EtOH, avoiding the use of DMF. Analyses included Fourier-transform infrared spectroscopy (FT-IR), fluorescence spectroscopy using Nile red as a probe, thermogravimetric analysis (TGA), solid-state 13C NMR, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) to characterize the HCP materials. The catalytic performance of the materials was evaluated by monitoring the reaction yields and recyclability of the catalysts.
10.1016/j.molstruc.2007.01.064
The research focuses on the synthesis, structure, and luminescent properties of a novel 3D porous metal-organic framework (MOF) with rutile topology, denoted as Cd(CTC)(HPDA)·(H2O) (1). The MOF was synthesized using 1,3-propanediamine (PDA) as a template, with cadmium chloride dihydrate and cis,cis-1,3,5-cyclohexanetricarboxylate (CTC) as reactants. The synthesis involved mixing these compounds in N,N-dimethylformamide, ethylene glycol, and water, followed by the slow diffusion of PDA at 65°C for five days, yielding colorless block-shaped crystals. The product was characterized using X-ray crystallography, which revealed a 3D network with quadrangular channels. The structure was further analyzed using thermogravimetric analysis (TGA), differential thermal analysis (DTA), powder X-ray diffraction (XRD), inductively coupled plasma (ICP) analysis, and infrared (IR) spectroscopy. The compound exhibited intense fluorescence at 364 nm upon excitation at 240 nm at room temperature, indicating potential as a photoactive material. The research was supported by several funding agencies and the crystallographic data was deposited with the Cambridge Crystallographic Data Centre.
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