10.1002/jhet.5570380514
The research focuses on the preparation of 6-, 7-, and 8-substituted derivatives of 2-oxa-1,3,4,10-tetraazacyclopenta[b]fluoren-9-one, a heterocyclic compound of interest for its potential pharmacological activity. The synthesis involves a series of chemical reactions, including oxidation, cyclization, and alkylation, starting from substituted indan-1-ones. Key reactants include ninhydrin derivatives, furazan-3,4-diamine, and various substituted indanones. The researchers utilized a range of analytical techniques to characterize the synthesized compounds, such as infrared (IR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, mass spectrometry (MS), and X-ray crystallography. These analyses confirmed the structures of the synthesized compounds and provided insights into their chemical properties.
10.1002/jccs.200500083
Raafat M. Shaker, Alaa F. Mahmoud, and Fathy F. Abdel-Latif present a novel method for synthesizing spiro-fused pyran derivatives using a three-component condensation reaction. The study focuses on the reaction of ninhydrin, malononitrile, and various nucleophilic reagents in the presence of piperidine under microwave irradiation without using solvents. This solvent-free approach offers several advantages, including reduced costs, minimized environmental impact, and enhanced safety by avoiding the use of toxic solvents. The synthesized compounds were characterized using elemental analysis, IR, 1H NMR, and MS spectroscopy, confirming their structures. The study highlights the efficiency and simplicity of the microwave-assisted synthesis method, which yields high-quality spiro-fused pyran derivatives with potential applications in pharmaceuticals and materials science.
10.1007/s11164-018-3659-7
This study presents the synthesis of montmorillonite (MMT) supported Fe3O4 magnetic nanoparticles, which were used as heterogeneous nanocatalysts for the one-pot synthesis of indeno[1,2-b]indolone derivatives in aqueous media. The MMT@Fe3O4 nanocomposites were characterized using various techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR). The catalyst exhibited high efficiency in promoting the cyclocondensation of ninhydrin, 1,3-diketone compounds, and amine derivatives to generate the desired indeno[1,2-b]indolone derivatives in excellent yields under mild conditions. This study highlights the advantages of using MMT@Fe3O4 as an environmentally friendly, cost-effective, and recyclable catalyst, providing a green and efficient approach for the synthesis of these heterocyclic compounds of biological and pharmacological importance.
10.1016/j.tetlet.2007.11.004
The research focuses on the development of a microwave-assisted method for the solid phase synthesis of pseudopeptides containing ester bonds, aiming to reduce reaction times and improve yields. The study utilized a pseudodipeptide (Fmoc-LysW[COO]Leu-NH2) as a model system and optimized the microwave-assisted esterification reaction using Fmoc chemistry. The experiments involved various reaction times, temperatures, and solvents, with 1,3-diisopropylcarbodiimide (DIC) as the coupling reagent. The synthesized pseudopeptides were analyzed for purity and yield, which were found to be superior when using the microwave irradiation method compared to conventional methods. The analyses included Fmoc quantitation assay, ninhydrin test, C18 reverse phase HPLC, and ESI mass spectrometry to confirm the structure and purity of the synthesized pseudopeptides.
10.1016/S0040-4039(00)96868-0
This study investigates the reactions of secondary α-amino acids with carbonyl compounds, focusing on the properties of the intermediate methylene ylides and their products. Cyclic secondary α-amino acids react with aldehydes bearing electron-withdrawing substituents to form oxazolidines via anti-dipoles. In some cases, structural features of the α-amino acid promote a 1,4-proton transfer process in the intermediate methylene ylides, leading to the formation of Z-pyrrolines. When ninhydrin is used as the carbonyl component, stable methylene ylides can be formed under favorable circumstances. This study explores factors that influence the reaction pathways, including the structures of the secondary α-amino acids and carbonyl compounds, and shows that these reactions can lead to a variety of products, such as oxazolidines, pyrrolines, and stable methylene ylides, which can undergo further cycloaddition reactions.
