Current organic synthesis最新文献

The current review aimed to provide an understanding of the preparation, reactions, and biological action of thiazoles. The purpose of this review was to focus on the progress made in the synthesis of physiologically effective thiazole products with their interactions. A combinatorial approach was proposed, and extensive attempts were made in the search for thiazoles by chemists in many domains due to the information of multiple artificial pathways and variable physics-chemical factors of thiazoles. In this regard, the biological activities linked to thiazole and the processes used in its production were thoroughly discussed in this study. The research period covered in this review was from 1905 to 2024, providing a useful and convenient strategy for the synthesis of numerous thiazole derivatives. Moreover, research on such reactions is still ongoing and undoubtedly will provide new fused functionalized compounds of both industrial and biological interests. A literature survey revealed that a great deal of interest has been focused on the synthesis and reaction of thiazoles due to their wide range of biological activities. Remarkable insights into different synthetic paths and modified physical-chemical features of such thiazoles would be helpful for chemists worldwide.

Natural products, with their various sources from plants, marine organisms, and microorganisms, are considered a key source and inspiration for medicines and continue to be so. Indole alkaloids are a class of alkaloids and represent a large subunit of natural products. Indole alkaloids of biological importance are numerous and cover a wide range of pharmaceutical applications, including anticancer, antiviral, antimicrobial, anti-inflammatory, and antioxidant. Obtaining natural, biologically active indole compounds involves isolating them from their natural sources or preparing them synthetically. 3-Substituted indoles represent an emerging structural class of marine alkaloids based on their high degree of biological activity. 3-Acetyl indole is an important core used as a starting material for synthesizing many bioactive indole alkaloids. (5-Indole)oxazole alkaloids, β-carboline alkaloids, bis-indole alkaloids, chuangxinmycin, meridianine, and (±) indolemycin are the most important indole alkaloids that are prepared starting from 3-acety indole. The present review provides comprehensive information on the structures and the synthesis of bioactive indole alkaloids utilizing 3-acetyl indole and its derivatives as starting compounds. Additionally, it also spotlights the diverse biological activities of these compounds.

Introduction: 1,4-oxazepine is a significant structural motif found in several bioactive molecules used in the treatment of diseases such as psychotic disorders.

Methods: Therefore, developing novel methodologies for its preparation is of great interest to medicinal chemists.

Results: These seven-membered heterocycles are generated through the intramolecular cyclization of Betti bases, which are propargylated using propargyl bromide as the source of the triple bond in the presence of a base.

Conclusion: This efficient and straightforward protocol proceeds under mild, metal-free conditions and has been shown to be applicable to a broad range of aldehydes and 2- aminopyridines.

Indolizidine alkaloids represent a diverse group of naturally occurring compounds which are derived from various sources and possess a wide range of pharmacological activities. Fused indolizidine alkaloids represent a distinct subset of these compounds, where additional rings are fused with the indolizidine core. When combined with the specific stereochemistry typically required for their biological activity, the fused ring structure complicates the synthesis of this important class of compounds. Among the well-studied fused indolizidine alkaloids are securinine, gephyrotoxin, and lepadiformine, which have all exhibited potential in important therapeutic areas. Due to their complex structures, over the years numerous approaches have been proposed to synthesize these compounds. In this article, we review the progress made in synthetic routes for these key fused indolizidine alkaloids throughout history, providing a broad overview and the distinct advantages of the various strategies that could be employed in their synthesis.

Introduction: This research introduces an eco-friendly, one-pot multicomponent synthesis of pyrimidopyrimidines (4a-4i) and amino-1,3-dimethylpyrimidines (5a-5d) in an aqueous medium, utilizing citric acid as a catalyst.

Aims: The study aimed to establish a sustainable method for synthesizing these heterocyclic compounds while evaluating their biological activities.

Methods: Structural characterization of the synthesized compounds was conducted through elemental analysis, IR, and NMR spectroscopy. The DPPH, TAC, and ABTS methods assessed the antioxidant properties, revealing their significant potential as bioactive agents. Compound 4i demonstrated the highest antioxidant activity with a DPPH inhibition of 99.13%, while compound 5b exhibited the highest ABTS activity of 100%. Advanced computational analysis using Density Functional Theory (DFT) at the B3LYP/6-311+G(d,p) level provided insights into the compounds' molecular structures, reactivity, and electronic properties.

Results: Key findings include the energy band gap analysis, which revealed compound 4c as the most stable (energy gap 5.102 eV) and compound 4i as the most reactive (energy gap 3.51 eV). These theoretical calculations, aligned with experimental NMR data, validated the molecular structures and confirmed the accuracy of theoretical predictions. Additionally, antibacterial and antifungal assays identified compound 4i as the most effective against Grampositive and Gram-negative bacteria and Candida albicans.

Conclusion: This work highlights the potential of these derivatives as promising candidates for therapeutic applications and contributes to advancing environmentally benign synthetic methodologies.

Background: o-Aminophenol derivatives are of particular interest for their diverse biological activities and potential therapeutic applications. Such as, antioxidant, antibacterial, and cytotoxic activities.

Objectives: This study aimed to design and synthesize a series of novel o-aminophenol derivatives through an efficient multi-step process, characterize them using modern spectroscopic techniques, and evaluate their antimicrobial, antioxidant, and cytotoxic activities.

Methods: A series of novel derivatives of o-aminophenol have been successfully synthesized with very high efficiency through a simple six-step process using readily available chemicals and straightforward reactions. The structures of all products were accurately determined using modern spectroscopic methods such as 1D and 2D NMR, as well as IR, MS spectroscopy, and X-ray methods. The antimicrobial activities of eight o-nitrophenol derivatives were assessed against Gram (-) and Gram (+) bacteria as well as fungi. In comparison, antioxidant activities were tested for two o-nitrophenol and 11 o-aminophenol derivatives using SC₅₀ and EC₅₀ assays. Cytotoxicity was evaluated on KB, HepG2, A549, and MCF7 cancer cell lines.

Results: Six synthesized compounds 5b, 5c, 5g, 6b, 6c, 6g exhibited unusual doublet signals in the H8 region of the ¹H NMR spectrum, attributed to atropisomer formation. Eight o-nitrophenol derivatives demonstrated weak antimicrobial activity, with MIC values ranging from 100 to 200 μg/mL. Compound 5g showed activity against all tested bacterial and fungal strains. In antioxidant testing, eight o-aminophenol derivatives 6a, 6b, 6c, 6e, 6f, 6h, 6i, and 12b displayed excellent activity, with SC₅₀ values between 18.95 and 34.26 μg/mL, approaching ascorbic acid's SC₅₀ value of 12.60 μg/mL. Three derivatives 6d, 6g, and 12a showed superior antioxidant activity with EC₅₀ values between 4.00 and 11.25 μg/mL, surpassing quercetin's standard of 9.8 μg/mL. Cytotoxicity assays revealed that oaminophenol derivatives 6b, 6c, 6f, 6i, and 12b exhibited moderate inhibitory effects on KB cell lines with IC₅₀ values from 32 to 74.94 μg/mL. Compound 6i demonstrated moderate cytotoxic activity against HepG2, A549, and MCF7 cell lines, with IC₅₀ values of 29.46, 71.29, and 80.02 μg/mL, respectively.

Conclusion: Design, synthesis, antimicrobial activity, DPPH Radical Scavenging, Cytotoxic activity, Evaluation of H8 signal anomalies in certain compounds, and Single crystal X-ray diffraction analysis.

Background and objectives: Despite the well-known antibacterial activity of cephalosporins, their analogous spirocyclic derivatives have not been adequately evaluated. Thus, this work aimed to prepare a series of novel 3-spirocephalosporins and evaluate their antibacterial activity.

Materials and methods: Novel 3-spirocephalosporins were prepared through a one-pot thioalkylation of chloromethyl cephalosporin GCLE with a range of 1,2,4-triazolidine-3- thiones, followed by intramolecular Michael addition to the generated dihydrothiazine ring. The reaction was performed at room temperature under basic conditions (K2CO3, acetone, H2O). The antibacterial activities of the synthesized compounds were evaluated against a panel of Gram-positive and Gram-negative bacteria.

Results: Most targets were obtained in moderate yield, and their structures were confirmed by ¹H and ¹³C NMR spectral techniques. All the tested compounds exhibited antibacterial activity against methicillin-resistant S. aureus.

Conclusion: Seven novel thiazolidine-bearing 3-spirocephalosporins were prepared, and most of them were potent against Gram-positive bacteria. Likely, the replacement of 1,2,4- triazolidine-3-thiones with other heterocycles containing bidentate nucleophiles in advantageous positions could lead to different biologically active spirocephalosporins.

Introduction: Quinazoline holds significant importance in pharmaceutical chemistry, which is included in a range of drugs, clinical contenders, and bioactive compounds. N-containing heterocyclic compounds of quinazoline have a wide and distinct range of biopharmaceutical activities.

Methods: A series of newly synthesized heterocyclic compounds, namely, N-(4-substituted benzylidene)- 2-(2-aminothiazol-4-yl)-6-methylquinazolin-3(4H)-amines (3a'-3e') and N-(4-substituted benzylidene)-2-(2-aminooxazol-4-yl)-6-methylquinazolin-3(4H)-amines (3a-3e), were synthesized starting from 6-methylquinazolin-3(4H)-amine and 4-substituted benzaldehyde and their antibacterial and antifungal properties were evaluated. Moreover, they were compared with the well-known drugs Imipenem (as an antibacterial agent) and Miconazole (as an antifungal).

Results: Compound 3c' exhibited higher potential activity compared to newly synthesized other compounds and standard drugs when tested against the microorganism.

Conclusion: The structure of substances was determined through elemental analysis (C.H.N.) and various spectroscopic technique (¹H NMR, ¹³C NMR, IR, and GCMS).

Oxazolines are important heterocyclic systems due to their biological activities, such as antibacterial, antimalarial, anticancer, antiviral, anti-inflammatory, antifungal, antipyretic, and antileishmanial. They have been widely applied as chiral auxiliaries, polymers, catalysts, protecting groups, building blocks, and ligands in asymmetric synthesis. Due to their importance, many synthetic routes to prepare oxazoline moieties have been investigated and developed by researchers around the world. In this review, we summarized several synthetic methodologies published in the literature. The main substrates are nitriles, carboxylic acids, and acid derivatives, which react with a variety of reactants under conventional heating, microwave irradiation or ultrasound irradiation conditions. Syntheses via intramolecular cyclisation from amides have also been reported. Many publications have highlighted procedures based on solvent-free conditions using eco-friendly, reusable, and easy-availability catalysts.