Journal of Heterocyclic Chemistry最新文献

To explore the room-temperature synthesis of metal phthalocyanines with unsaturated substituents, two zinc phthalocyanines with unsaturated alkoxy groups were synthesized in a reaction system composed of 4-citronellol-oxy-phthalonitrile or 4-geraniol-oxy-phthalonitrile, Zn(OAc)₂⋅2H₂O, DBU, and ethanol, at room temperature. The synthetic reactions lasted for 7 days and the yields of two phthalocyanine derivatives reached 21% and 18%, respectively, and they are inclined to protonation in a non-coordinated organic solvent, for example, CHCl₃. By the way, the phthalocyanine compounds with other metals, such as Cu, Ni, and Co, cannot be prepared. This work will provide preference for improving the synthetic method in the future, so as to synthesize many new phthalocyanine compounds in general laboratories.

A rapid and direct route with the help of ultrasound for the synthesis of benzo[1,4,2]dioxazine derivatives through a copper iodide-catalyzed intermolecular O-arylation of N-hydroxyimidoyl chloride and 2-iodophenol in acetonitrile solvent has been investigated. The use of cheap and available raw materials and catalysts, without column chromatography, applying the sonochemical methodology, and performing the reaction in 40–45 min, with good efficiency (71%–93%) are notable features of this protocol. This research represents a significant advancement in the synthesis of benzo[1,4,2]dioxazine derivatives.

Nowadays, environmentally sustainable organic synthesis is demanding. In this context, nanoparticles are particularly interesting owing to their green synthesis aspects. Specifically, magnetic nanoparticles have been continuously utilized in organic synthesis for a decade. Among heterocycles, pyrrole and its analogs have a unique place due to its vast spectrum of applications. Derivatives of pyrrole help to find lead structures for new synthetic pharmaceutical compounds and other valuable compounds. Thus, magnetic nanoparticles accelerate organic chemists to develop pyrrole derivatives through green synthesis. Moreover, magnetic nanoparticles in pyrrole scaffold synthesis improve reaction efficiency and sustainability and create unique functional molecular hybrids for many scientific applications. This paper reviews the utilization of magnetic nanoparticles to afford a variety of valuable pyrrole derivatives, with a focus on their environmental friendliness.

The present protocol shows a novel and greener approach for synthesizing pyrazole amine thioether, employing thiophenol, 3-aminocrotononitrile, and phenylhydrazine hydrochloride. Notably, this methodology deviates from the literature report in making thioether derivatives using oxidant-free and room-temperature conditions. Based on the control experiments, it was found that the thioether link in the intermediate facilitated the 5-exo-dig cyclization reaction exclusively in the DMSO solvent. This is probably due to the nitrile group's activation by the structure's thioether moiety. The control experiment demonstrates the significance of the thioether compound in the reaction. Without any oxidizing agent, introducing thioether in any heterocyclic compound is not possible, as per the literature reports. Our reaction showed excellent tolerance by involving various phenylhydrazine hydrochloride and thiophenol compounds, allowing for the synthesis of various pyrazole amine thioether derivatives in good to excellent yields. The reaction follows the 5-exo-dig cyclization strategy.

CuI–Zn(OAc)₂ catalyzed a new, fast, solvent-free strategy for the synthesis of quinazolin-4(3H)-ones via selective scission of CC bond of the 1,3-diketone (both cyclic and acyclic) and β-ketoester was achieved under microwave irradiation. In contrast to the frequently applied synthetic strategy that involves cyclization-oxidation sequence of anthranilamides (2-aminobenzamides) with various aldehydes or benzyl alcohols, here, anthranilamide reacts with β-ketoester/1,3-diketo compounds in presence of CuI-Zn(OAc)₂ catalyst to form quinazolin-4(3H)-ones scaffold through an uncommon CC bond cleavage under solvent-free mild conditions with excellent yields. Besides, this method displays its capacity for gram-scale reactions.

A straightforward and an efficient green synthetic method has been outlined for the construction of 3-(benzo[d][1, 3] dioxol-5-yl)-1,8-naphthyridine derivatives in the presence of glacial acetic acid and Cu(OAc)₂ catalyst accomplished excellent yields in short reaction time. The reaction proceeds efficiently by using a greener way under microwave conditions to elevate the quantity of pure products. The purity of all the synthesized compounds was confirmed by IR, ¹H and ¹³CNMR, LC–MS data and also from the elemental analyses studies. The synthesized compounds 7d and 7f performed strongest antibacterial activity against pathogenic cell lines Bacillus subtilis (17.5, 20.5 mm), Escherichia coli (28.5, 30 mm), and antifungal cell lines Candida albicans (18, 22.5 mm), and Aspergillus Niger (28.5, 40.5 mm) which are compared with clinical drugs Penicillin, Grieseofulvin. We scrutinized the remaining molecules and found that their activity ranged from modest to exceptional.

A highly efficient method for the synthesis of 2′H-spiro[indene-2,3′-pyrano[2,3-c]chromene] derivatives 20(a–s) has been developed involving oxa–Diels–Alder reaction as the key step under conventional conditions in good to excellent yields. The compounds were all characterized using ¹H, ¹³C NMR, HRMS, and X-ray crystallography. The present study employs DFT to validate the reaction pathway. In vitro antibacterial assay of all the synthesized derivatives was evaluated against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacterial strains. Compound 20e was found to be the most potent molecule with ZI of 19 mm and MIC of 16 μg mL⁻¹ in E. coli and ZI of 14 mm and MIC of 32 μg mL⁻¹ in S. aureus. Additionally, 20e demonstrated a strong inhibition of DNA gyrase in silico, with a binding affinity of −9.3 and − 9.0 kcal/mol in E. coli and S. aureus respectively. Also, significant pharmacokinetic, physicochemical, and drug-like properties of the spirocyclic compounds were further corroborated by ADME investigations. Hence, these new series of spiro indanone fused pyrano[2,3-c]chromene derivatives may be potent druggable antibacterial agents in future.

2-Thioxo-4-thiazolidinone which is trivially known as rhodanine is a five-membered heterocycle, containing a sulfur and nitrogen atom at 1 and 3 positions, respectively. It is a very attractive class of compounds, because derivatization of rhodanine yields a number of molecules having multifarious application in medicinal chemistry and biology. There are many molecules derived from rhodanine which are already being used commercially as drug molecules. So owing to the importance of rhodanine in the field of medicinal chemistry and biology, a comprehensive review familiarizing different derivatives of the parent molecule rhodanine and their syntheses is highly warranted. In this review, we have broadly categorized the reactions of rhodanine as; (a) Knoevenagel condensation through the C-5 active methylene group with carbonyl compounds, (b) nucleophilic attack on thioxo group at position 2 of rhodanine by aliphatic amines, (c) thioxo to oxo conversion, and (d) all other reactions. So far, to the best of our knowledge, no such literature which accounts for all the different kinds of reactions of rhodanine is reported. Here, we have not only presented the reactions schemes from various literatures, but we have discussed about the advantages and inadequacies of that particular catalytic processes. Moreover, at the end of this article we have given our own critical analysis on these literature reports, based on our understanding and experience.

A highly selective fluorescent sensor Por-RBO for determination of Hg²⁺ was designed and synthesized with Rhodamine B and Tetraphenylporphyrin. The sensor can determine the Hg²⁺ of a solution within the pH 5.0–8.0, free from interference of other metal ions. When detected in buffer solution, the fluorescence was the strongest when five times the concentration of Hg²⁺ ion was added. Calculated by fluorescence titration method, the detection limit of sensor Por-RBO for Hg²⁺ ion was as low as 0.12 μmol/L. The geometries of Por-RBO and Por-RBO-Hg²⁺ were optimized at the B3LYP/6-31G** level by density functional theory. The charge distribution, orbital interactions, and bonding characteristics were analyzed and compared in detail to discuss the recognition mechanism and structure–fluorescence property relationships. The results of cell fluorescence imaging and CCK-8 experiments indicate that the sensor Por-RBO exhibits lower cytotoxicity. Por-RBO can be used for fluorescence distribution imaging of Hg²⁺ in living cells.