Graphene-supported ZnO nanoparticles: An efficient heterogeneous catalyst for the Claisen-Schmidt condensation reaction without additional base
作者:Zhuofei Li、Hongyan Zhao、Huatao Han、Yang Liu、Jinyi Song、Weihao Guo、Wenyi Chu、Zhizhong Sun
DOI:10.1016/j.tetlet.2017.09.011
日期:2017.10
catalyst, ZnO/RGO was applied to the Claisen-Schmidt condensation reaction of aryl aldehydes and aryl ketones undermicrowaveirradiation. Therein, chalcone products could be efficiently synthesized and easily separated from the heterogeneous catalysis system. The catalyst could be recycled four times without significant loss of catalyticactivity.
A cost-effective, practical, straightforward and scalable synthesis of α-pyrones via base- and sulfur-promoted annulation of phenylacetates and chalcones is reported. Generated in situ from the starting components by using dbu as a base catalyst, the Michael adducts underwent a smooth oxidative cyclization into 3,4,6-triaryl-2-pyranones upon heating with DABCO and sulfur in DMSO. Extension to malonate
Novel sixteen chalcones and thirteen 1,3,5‐triphenyl‐2‐pyrazolines were synthesized and characterized using FT‐IR, HR‐Mass, NMR (1H‐NMR, 13C‐NMR, 135 DEPT, 1H–1H CoSY and 1H and 13C CoSY) and XRD. These compounds were evaluated for their antibacterial activity against six micro‐organisms, namely Bacillus subtilis NCIM 2718, Staphylococcus aureus NCIM 5021, Salmonella typhi NCIM 2501, Enterobacter aerogenes NCIM 5139, Pseudomonas aeruginosa NCIM 5029, and Proteus vulgaris NCIM 2813 by twofold dilution method using resazurin as the indicator dye. In the case of chalcones, compounds with hydroxyl and bromo substitutions in the B‐ring favor activity and benzyloxy substitution irrespective of its position in the A‐ring. In the case of 1,3,5‐triphenyl‐2‐pyrazolines, chloro substitution in the A‐ring favors activity. Hydrophilic/lipophilic balance of the compounds plays a major role in their antibacterial activity.