Synthesis of benzoin under supramolecular catalysis involving cyclodextrins in water: application for the preparation of the antiepileptic drug phenytoin

TEMPO/PhI(OAc)2 promotes the α-aminophosphinoylation of alcohols with amines and H-phosphine oxides in aqueous medium

A novel method for synthesizing α-aminoalkyl phosphine oxides in aqueous medium, using Ar2P(O)-H reagents, alcohols and amines, is described. This method: (i) allows for the smooth aminophosphinoylation of alcohols with amines and H-phosphine oxides under mild conditions; (ii) provides an efficient and alternative approach to access various α-aminoalkylphosphine oxides. Although various amines exhibited remarkable versatility and tolerance for functional groups in this reaction, alcohols and H-phosphine oxides demonstrated limited applicability as reactants. Hence, further investigation using a wider range of substrates is crucial. The postulated mechanism indicated that the three-component reaction followed the imine pathway due to the in situ oxidation of alcohol to aldehyde.

Inclusion complexes of capsanthin with acyclic cucurbit[n]urils to improve its stability and antioxidant capacity

Capsanthin is a natural red pigment widely used in the food industry, but its pigment is severely lost during use and storage. Supramolecular chemistry-based macrocyclic hosts can encapsulate small molecule pigments to improve their stability and solubility. Herein, we synthesized two acyclic cucurbit[n]urils (ACBs, M1 and M2) as carriers for encapsulating capsanthin, and we expect this strategy to generate some positive improvements on the properties of capsanthin, extending its use by the food industry. Successful host-guest inclusion complexes (IC) formation was confirmed via 1H NMR, 2D-ROESY NMR, 13C NMR, XRD, and FT-IR. After encapsulation, the solubility of capsanthin was increased by 75.8 times and 62.3 times, respectively. Furthermore, the storage and utility of capsanthin was enhanced due to the phase transition from oil to solid powder. IC exhibited enhanced stability for capsanthin in challenging environments, such as high temperature, light exposure, acidity, metal ions, food additives, and extreme oxidation.

l-Asparagine-EDTA-amide silica-coated MNPs: a highly efficient and nano-ordered multifunctional core-shell organocatalyst for green synthesis of 3,4-dihydropyrimidin-2(1H)-one compounds

In this study, new l-asparagine grafted on 3-aminopropyl-modified Fe3O4@SiO2 core-shell magnetic nanoparticles using the EDTA linker (Fe3O4@SiO2-APTS-EDTA-asparagine) was prepared and its structures properly confirmed using different spectroscopic, microscopic and magnetic methods or techniques including FT-IR, EDX, XRD, FESEM, TEM, TGA and VSM. The Fe3O4@SiO2-APTS-EDTA-asparagine core-shell nanomaterial was found, as a highly efficient multifunctional and recoverable organocatalyst, to promote the efficient synthesis of a wide range of biologically-active 3,4-dihydropyrimidin-2(1H)-one derivatives under solvent-free conditions. It was proved that Fe3O4@SiO2-APTS-EDTA-asparagine MNPs, as a catalyst having excellent thermal and magnetic stability, specific morphology and acidic sites with appropriate geometry, can activate the Biginelli reaction components. Moreover, the environmental-friendliness and nontoxic nature of the catalyst, cost effectiveness, low catalyst loading, easy separation of the catalyst from the reaction mixture and short reaction time are some of the remarkable advantages of this green protocol.