Refernces
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.tet.2008.08.092
The research focuses on the control of Twisted Intramolecular Charge Transfer (TICT) and Photoinduced Electron Transfer (PET) processes in N-phenyl-9-anthrylcarboxamide derivatives through chemical modifications. The study investigates how the introduction of methoxy groups and a methylene spacer affects fluorescence properties, which are indicative of TICT and PET processes. Experiments involved synthesizing various derivatives with different substituents and measuring their fluorescence and UV spectra in different solvents to assess solvent dependence. The synthesized compounds included N-(2-methoxy or 4-methoxyphenyl)-9-anthracenecarboxamide (1 or 2), N-(2-methoxy-, 4-methoxy-, or 3,4-dimethoxy-phenyl)-9-anthraceneacetamide (3, 4, or 5), and crown ether derivatives 6 and 7. 9-Anthracenecarboxylic acid (9-anthroic acid)was used as a starting material for the synthesis of compounds 1 and 2. HOBt (1-hydroxybenzotriazole)was used as a coupling agent in the synthesis of compounds 3-7. The analysis showed that the TICT process was dominant in compound 1, whereas PET was more significant in compound 2. The introduction of a methylene unit in compounds 3 and 4 modulated fluorescence emissions, and the presence of two methoxy groups in compound 5 enhanced the PET process. The crown ether derivative 7 showed a high response to Mg2+, with a significant fluorescence enhancement upon complexation, attributed to the disruption of p-conjugation. The research utilized spectroscopic techniques to elucidate the photochemical properties and the influence of molecular motion on CT processes, providing insights into the design of chemosensors and fluorescent materials.
10.1021/jo015703t
The research focuses on the synthesis of the cyclic heptapeptide Trunkamide A, a biologically active compound derived from marine organisms, specifically the colonial ascidian Lissoclinum sp. The study outlines a solid-phase approach for the total synthesis of Trunkamide A, which includes the use of a quasi-orthogonal protecting scheme with tert-butyl and fluorenyl-based groups on a chlorotrityl resin, HOAt-based coupling reagents, and cyclizations in solution. Key reactants in the synthesis process include Fmoc-protected amino acids, DIPCDI, HOBt, and DAST, among others. The synthesis involves several steps such as the preparation of reverse prenyl derivatives of Ser and Thr, introduction of a protected amino thionoacid derivative, and formation of the thiazoline ring with DAST. The synthesized product was analyzed using techniques like HPLC, ES-MS, HRMS, and NMR spectroscopy to confirm its structure and purity. The research also discusses the challenges and optimizations in the synthesis process, making it suitable for large-scale synthesis of Trunkamide A and related peptides.
10.1016/j.bmc.2015.02.055
The research focuses on the design, synthesis, and pharmacological evaluation of a series of 17-cyclopropylmethyl-3,14b-dihydroxy-4,5a-epoxy-6a-(isoquinoline-3-carboxamido)morphinan (NAQ) analogues. These compounds were developed to study their structure-activity relationship at the mu opioid receptor (MOR). The experiments involved competition binding assays, functional assays like the [35S]GTPcS binding assay, and in vivo tests such as the warm-water tail immersion assay for antinociception and opioid withdrawal assays in mice. The reactants used in the synthesis of these analogues included substituted isoquinoline-3-carboxylic acids and naltrexone derivatives, with coupling reactions facilitated by EDCI/HOBt. The analyses included radioligand binding assays for receptor affinity and selectivity, functional assays for agonism/antagonism at MOR, and in vivo assays for antinociceptive effects and opioid withdrawal symptoms. The study also utilized molecular dynamics simulation to understand the binding affinities and selectivity of the compounds at different opioid receptors.
10.3987/COM-04-10206
The research focuses on the development of a new synthetic method for producing 2,3,6-tri- and 2,3,5,6-tetrasubstituted pyridine derivatives, which are key structural components of thiostrepton-type macrocyclic antibiotics. The synthesis is achieved starting from L-α-aspartic acid through the use of an α-dehydroamino acid derivative. The study involves a series of chemical reactions, including esterification, reduction, oxidation, and cyclization, utilizing reagents such as DCC, HOBt, NaBH4, SO3.pyridine, Jones reagent, MnO2, MeI, Ag2CO3, and Pd-C/H2. The analyses used to characterize the synthesized compounds include melting point measurements, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis, which confirm the structure and purity of the products.
10.1055/s-0030-1259988
The research aims to develop a simple and practical protocol for reducing carboxylic acids to alcohols using hydroxybenzotriazole esters as intermediates. The study explores the use of 1-hydroxybenzotriazole (HOBt) and carbodiimide (EDC) to form these reactive intermediates, which are then reduced by sodium borohydride in the presence of water. The researchers found that the reaction proceeds with excellent yields and tolerates various functional groups, including methoxy, phenoxy, and nitro groups. The protocol was successfully applied to a wide range of carboxylic acids, including phenylacetic acids, benzoic acids, and amino acids, yielding the corresponding alcohols in high yields. The study concludes that this method provides a general, rapid, and convenient approach for the reduction of carboxylic acids, making it a useful tool for selective reduction in the synthesis of complex molecules.
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