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An efficient synthesis of 1,4-dihydropyridine & polyhydroquinolien derivatives using b-Cyclodextrin-polyurethane polymer (β-CDPU) as a stationary microvessel and neutral heterogeneous catalyst via a four component coupling of aldehydes, β-ketoester (2 mol) and ammonium acetate under solvent-free conditions is described. Compared with the classical Hantzsch reaction, this new method has the advantages of good yield, short reaction time and methodological simplicity. β-CDPU was proved to be an efficient heterogeneous catalyst which could be easily handled and removed from the reaction mixture by simple filtration, and also recovered and reused without loss of reactivity.

The anti‐microbial property‐based packaging system is able to destroy and eliminate the contaminants and pathogenic microorganisms, which spoil the food. In this study, sachets were prepared by an active packaging system using starch‐based microcellular foam loaded with peppermint essential oil (SMF‐PEO). The produced SMF was used to make sachets loaded with PEO and then placed on the upper part of the strawberry package. Qualitative and biochemical traits of the strawberry fruits, such as weight loss percentage, vitamin C, phenolic substances, antioxidant capacity, anthocyanin, malondialdehyde, hydrogen peroxide content, microbial load, and antioxidant enzymes activity, were evaluated. Results of the gas chromatography confirmed EO release until the end of the fourth day of the fruit storage. Fourier‐transform infrared spectroscopy spectra showed the porosity of the SMF and the loading of PEO in its pores. Total phenol and antioxidant activity decreased during storage. At the end of storage, the most total antioxidant activity (29.04 iron II mol g−1) was found in packaged fruits with sachet, whereas the most anthocyanin (896 mg kg−1) was found in control. At the end of the storage period, the treated fruits showed a greater catalase (1660 U kg−1) and phenylalanine ammonia‐lyase (1626.6 U kg−1) activity. Packaged fruits with sachet had lower microbial load, total mesophilic bacteria in control and treated samples was 3.7 and 1.7 Log CFU g−1 in end during storage. At the end of storage, the total yeast + mold in treated and control fruits was 1.3 and 1.57 Log CFU g−1, respectively. Practical applications: The sachets loaded with PEO increased activity of enzymes and the decreased amount of malondialdehyde have a positive effect on increasing the shelf life of strawberry fruits and are efficient enough to reduce microbial load. Due to the inexpensiveness and degradability of starch, SMF is a suitable system for PEO loading. [ABSTRACT FROM AUTHOR]

In this work, a novel strontium-asparagine (Asn) complex has covalently immobolized over the surface of graphene oxide via post synthetic modification approach. Sr was introduced in the material in order to provide a basic environment. Asn has been a very good template to stabilize the Sr species in the complex. Structural features of the material was investigated by different methods like FT-IR, SEM, EDX, elemental mapping, TEM and TGA. The as-synthesized nanocomposite was successfully employed in the synthesis of diverse bis-coumarins or dicoumarols by assembling 4-hydroxycoumarin and different aromatic aldehydes. The product was obtained in refluxing EtOH in outstanding yields and within very short time. In order of reusability, the catalyst was retrieved by centrifuger and recycled 5 successive times without appreciable loss in its activity. Heterogeneity of the material was studied by hot filtration test. The bis-coumarin products were obtained just by recrystallization form hot EtOH and there was no requirement of column chromatography in isolating the pure product. [ABSTRACT FROM AUTHOR]