Tetrahedron最新文献

In the present scenario, environment-friendly reactions in organic synthesis have a unique and irreplaceable place. In the past, there are significant progress in the development of more nature-friendly and sustainable methods for various organic transformations. The nature-friendly and sustainable methods make a tool named green synthesis which utilizes for the synthesis of various drug candidates. Within perspectives of green synthesis, the magnetic nanoparticles attract considerable attention due to its many characteristics and utilization in the green synthesis. In organic synthesis, magnetic nanoparticles have been used as a green catalyst for the formation of various heterocycles. In the realm of organic compounds, imidazole is considered a preferred and highly valuable motif among aza-heterocycles. It presents a favourable opportunity for discovering lead structures in the quest for new synthetic molecules with potential therapeutic properties and other significant prospects. The synthesis of imidazole due to its exciting profile is very much demanding by using magnetic nanoparticles as a green catalyst. Accordingly, the pure and functionalized magnetic nanoparticles display significant potential in the synthesis of a diverse range of imidazole derivatives. Therefore, this manuscript compiles the current research (from 2004 to present) on the role of environmentally safe pure and functionalized magnetic nanoparticles for generating a wide variety of valuable imidazoles.

Biomercaptan, bisulfite (HSO₃⁻) and hydrogen sulfide (H₂S) are involved in many physiological and pathological processes in the human body. Therefore, it is of great significance to develop a fluorescent probe that can simultaneously detect and distinguish biological mercaptans from HSO₃⁻ and S²⁻. The probe CDI-1 was synthesized by combining coumarin with hemicyanine. The maximum absorption wavelength of the probe is at 609 nm. After adding Cys/Hcy and GSH, the probe shows varying degrees of blue shift, which can be used to distinguish Cys/Hcy and GSH. After it reacts with Cys/Hcy, the fluorescence intensity of the solution increases about twice, while it increases three times after it reacts with GSH. This phenomenon can also be used to distinguish Cys/Hcy from GSH. The probe CDI-1 can react with Cys completely within 30 min, with Hcy or GSH completely within 80 min, and with HSO₃⁻ and S²⁻ quickly within 20 min. The study on the effect of pH on the fluorescence performance of CDI-1 shows that the probe is suitable for detecting biological mercaptan or HSO₃⁻, S²⁻ in weak acid to weak alkali environments. The selectivity study showed that the probe CDI-1 had high specificity for biological mercaptan, HSO₃⁻ and S²⁻. This provides a new and simple method for simultaneous detection of biological mercaptan, HSO₃⁻ and S²⁻ ions.

Because of the important biological properties of β-amino acids in the present work, two new β-amino acid ethyl ester derivatives were synthesized, and their mechanistic occurrence was investigated. The title compounds were synthesized from related tetralone derivatives containing bromine and methoxy groups. Tetralone derivatives were reduced to their benzyl alcohol derivatives with NaBH_4, followed by elimination with p-toluenesulfonic acid (pTSA) to give the desired 1,2-dihydronaphthalene derivatives. The reactions of 1,2-dihydronaphthalenes with chlorosulfonyl isocyanate (CSI) afforded β-lactams. β-Amino acids were obtained from the reaction of β-lactams with EtOH in HCl. Computational studies are concerned with synthesizing four-membered lactams (β-lactam) formed by the reaction between 1,2-dihydronaphthalene derivatives and CSI. The mechanism of the formation of compounds has been elucidated using DFT at M06-2X.

An efficient, scalable and stereoselective synthesis of optically pure (3R,4R)-1-benzyl- and (3R,4R)-1-Boc-3-methyl-4-aminopiperidines has been developed starting from commercially available N-benzyl-3-methyl-4-piperidone. The synthesis employed chiral resolution of N-benzyl-3-methyl-4-piperidone, cis-selective reduction of a keto group, and subsequent Mitsunobu inversion of the resulting hydroxy group to install an amine with the desired trans-stereochemistry as the key steps. The method described herein demonstrated a competent route to the title compounds in a cost-effective, and scalable manner.

An efficient protocol for the synthesis of 2,2-disubstituted indolin-3-ones from both 2-aryl and 2-alkyl indoles via photoredox-catalyzed self-dimerization and cross-addition as well as Zn(OTf)₂-mediated nucleophile coupling is described. The photoredox reactions feature low catalyst loading, mild reaction conditions, and broad functional group tolerance, generating indolin-3-ones in moderate to excellent yields. The Zn(OTf)₂-mediated transformation using indolin-3-one dimer as a newly active species provides a much gentle way to access structurally diverse indolin-3-ones.

An alternative and efficient synthetic route for Relugolix was accomplished by changing the construction order of three main parts A, B and C. After the optimization, its scale-up of the preparation for Relogulix was completed in a seven-step methodology with overall yield of 61 % and 99.62 % HPLC purity.

The present review article offers an overview of the application of coumarin-3-carboxylic acids as a promising synthon in the synthesizing a diverse array of interesting biologically relevant organic molecules. This is accomplished, primarily through cross-coupling reactions, followed by subsequent decarboxylation, resulting in new reactivity patterns. The ability of the carboxylic acid moiety to enhance the electrophilic character of the directly attached olefinic carbon within a coumarin moiety, along with its feasibility for decarboxylation, opens up straightforward synthetic routes for numerous coumarin-derived molecules, including fused and hybrid heterocycles with remarkable regioselectivity (3-addition, 4-addition, or both). These advancements are primarily based on cascade reactions. This review article aims to provide readers with an up-to-date overview, encompassing contributions predominantly made in this challenging domain of organic synthesis during the last decade.

The quest for organic materials with compliant mechanical properties has significantly increased in the past few years in materials science and engineering. Crystalline organic compounds are excellent candidates for exploring and developing those long-lasting properties in the solid state since their fine structural functionalization may provide them with unique flexible behaviors. This study describes the 1,4-bis(phenylethynyl)benzene butyl ester synthesized in four steps and whose crystal can display elastic and elasto-plastic responses upon action with an external stimulus. A detailed characterization by single crystal X-ray diffraction revealed a layered crystal array that results from π-π stacking interactions, C–H⋯O and C-H⋯π bonds. Complementarily, variable temperature solid-state ¹³C and ²H NMR studies were carried out to probe the motion of the different components of the molecule and explore their possible association with the mechanical features. The compiled evidence indicates that the central phenylenes and the butyl groups experience molecular motion at different timescales, which, combined with the crystal array, facilitate the observed elastic and elasto-plastic flexibility. The results presented here not only contribute to advancing our understanding of flexible behavior but also could inspire potential applications such as flexible electronics.

An efficient [3 + 2] cycloaddition reaction involving vinyl acetates with tri/difluoroacetohydrazonoyl bromides has been established. This reaction provides an efficient method for synthesis of highly valuable ring-fused fluoroalkyl pyrazoles in moderate to good yields under mild reaction conditions, exhibiting remarkable regioselectivity and broad substrate scopes. The strategy further demonstrated that tri/difluoroacetohydrazonoyl bromides are effective tri/difluoromethyl building blocks for synthesis of fluoroalkyl heterocycle compounds.

We present a comprehensive review of the photochemical and electrochemical methodologies employed in the α-C–H functionalization of tertiary amines. The discussion starts with an introduction to α-C–H functionalization strategies, emphasizing the generation of radical species. The iminium ion and α-aminoalkyl radical are identified as key intermediates interacting with various organic functional groups. The review is divided into two main sections: photocatalytic and electrocatalytic α-C–H functionalization. In the photocatalytic section, we classify the functionalization into photocatalyst-mediated and photocatalyst-free approaches. Photocatalyst-mediated functionalization is further categorized into four mechanisms: Nucleophilic substitution, Transition-metal complexing, Giese-type reaction, and Radical-radical cross-coupling. Photocatalyst-free functionalization focuses on the direct excitation of the substrate and the EDA complex pathways, with particular emphasis on the latter. The electrocatalytic section explores both direct and indirect electrolysis techniques, highlighting the role of redox mediators in the indirect approach. Each section critically analyzes recent research examples from the past five years. This review aims to elucidate the current state of α-C–H functionalization research and suggest promising directions for future investigations.