Journal of Heterocyclic Chemistry最新文献

Protected lysine esters (Boc-L-Lys(Boc)-OSu) an intermediate of high repute in the peptide synthesis and diverse chemical synthetic applications, was the subject of synthetic process development studies, unveiling process-related impurities. These impurities were synthesized, characterized, and identified by different analytical tools, with their retention times verified by HPLC co-injection with commercial products. Detailed discussions ensued on the potential formation pathways and synthetic strategies of these process-related impurities.

Controlled oxidation of methyl-ketones to aryl glyoxals using Selenium dioxide and iodine is one of the useful transformation. Regardless the availability of many oxidation reagents, Iodine/DMSO system is very efficient and flexible. This system efficiently allows in situ formation of α-halo ketones and subsequently transforming them directly to useful products. The Iodine/DMSO system allows the selective CI and CO bond formation, substantially useful for converting them to other bond forming reactions and heterocycles useful in the synthetic and medicinal chemistry. Iodine/DMSO system could be an important alternative strategy due to sustainability, metal-free conditions, allowing multiple/linear domino reactions. This review will focus on heterocyclic systems smartly developed/manipulated by Wu group from methyl-ketones. The scope and limitations of this method and selected examples of applications for the synthesis of interesting molecules are discussed herein.

A rapid and efficient protocol for synthesizing two series of benzofuran-based hybrid polyheterocycles is presented: benzofuran-isatin and benzofuran N-acylhydrazones, and evaluation of their antibacterial activity both in vitro and in silico against two strains of Pseudomonas aeruginosa, PAO1 and PA14 were determined. Six of the tested compounds were shown to be active against the hypervirulent strain PA14. Docking studies were conducted using RNA polymerase sigmaS protein for P. aeruginosa PAO1 and PqsE protein for P. aeruginosa PA14 to provide additional insights into these results. A pharmacophore model was computed to suggest potential structural derivatives on the target molecules, offering further insights for future research. Finally, 40 novel compounds, including intermediates, were synthesized in a three-step reaction.

Antimicrobial resistance is one of the biggest threats to public health across the globe. Bacteria, fungi, viruses, and protozoans have been exhibiting resistance against antimicrobial drugs making them ineffective. Hence, the development of new antibiotics with a different mode of action is highly desirable. In this study, 10 new chromone-incorporated fused thiazolo[2,3-b]quinazolinone derivatives, 8a-j, have been prepared via Biginelli reaction involving aromatic aldehydes, 1-tetralone, and thiourea followed by a reaction with 2-chloro-N-phenylacetamide, and Knoevenagel condensation with 3-formylchromone. All the structures of the compounds were characterized by NMR, FTIR, and mass spectrometry. The in vitro antibacterial activities of all the synthesized compounds against the four different microbial strains were evaluated. Among them, few compounds demonstrated prominent activity against Staphylococcus aureus, Streptococcus pyogenes, and Pseudomonas aeruginosa. No appreciable activity of any compound against Klebsiella pneumoniae was observed. Molecular docking studies were employed to reveal the interactions responsible for the potent compounds' activities against S. aureus, S. pyogenes, and P. aeruginosa. Both in vitro and in silico studies have been carried out by using standard agar well diffusion protocol and Auto Dock Vina in PyRx. The results indicated that compound 8c was the potential compound as it showed good affinity toward the receptors of all three organisms. Molecular dynamics simulation of the 8c-1JIJ complex for 100 ns further confirmed the potentiality of 8c. The pharmacokinetic properties of the compounds indicate that the studied molecules have exhibited a favorable profile.

A large series of previously unknown isoxazole containing difluoroboron β-diketonate has been designed and synthesized from the available starting compounds. The photophysical properties of obtained compounds were studied, and the effects of the substituents in aromatic and isoxazole cycles of the BF₂ complexes on the fluorescence were investigated. The effect of solvatochromism were demonstrated. Cytotoxic activity against MCF-7 (breast carcinoma), HCT-116 (colon carcinoma), A549 (pulmonary carcinoma) and WI38 (fibroblasts from lung tissue) cell lines was tested and moderate toxicity in the concentration range of 10–100 μM was found for several compounds.

A concise and efficient synthesis of the γ-lactam-fused azaphenanthrene alkaloid eupolauramine has been achieved. The key feature of the synthesis involves Au(I)-catalyzed cycloisomerization of N-naphthyl aminobutynamide intermediate and subsequent intramolecular Ullmann-type coupling reaction. This study clearly demonstrated the usefulness of coinage metal-catalyzed cycloisomerization strategy in the construction of architecturally sophisticated pyridine-fused heterocyclic scaffolds.

A one-pot, three-component reaction of ethyl 5-aminobenzofuran-2-carboxylate, arylglyoxals and cyclic 1,3-dicarbonyl compounds in the presence of acetic acid as an organocatalyst in ethanol medium under reflux conditions provided a series of new 6H-furo[3,2-e]indole derivatives in good yields.

This work presents the study results on the acid-catalyzed cascade condensation of p-toluenesulfonamide with glyoxal in H₂SO₄ in order to synthesize aza- and oxaazaisowurtzitanes—a platform for promising high-energy-density compounds—and explore their formation processes. The effects of the ratio of starting reactants, acidity, reaction medium concentration, and temperature on this process were studied in detail. Five novel compounds were derived, including four oxaazaisowurtzitanes comprising one to three aza groups, and one condensation intermediate. The most favorable conditions for the formation of the resultant caged compounds were established and some new regularities of the process were revealed. For instance, the reaction medium concentration was discovered for the first time to influence the generation process of oxaazaisowurtzitanes via direct condensation. The limiting stage of the cage formation process of oxaazaisowurtzitanes was identified. The formation rate of the oxaazaisowurtzitanes was shown to be dependent on their structure. The factor dramatically reducing the yield of the oxaazaisowurtzitanes at elevated synthesis temperature was also revealed.