Synthesis and Biological Activity of Chalcone Derivatives Containing Thiazoxime Ethers

In this paper, a series of chalcone derivatives containing thiazole oxime ether structures were designed and synthesized from the natural product chalcone. The structures of these compounds were characterized using nuclear magnetic resonance ( NMR ) and high‐resolution mass spectrometry ( HRMS ). The results of antiviral activity tests showed that some of the target compounds exhibited better inhibition. Among them, S3 , S4 , and S16 exhibited better therapeutic activities with EC 50 values of 18.6, 66.9, and 61.8 μg/ mL , respectively, which were superior to that of the control drug ningnanmycin (158.3 μg/ mL ). The target compound S3 showed good protective activity with an EC 50 of 88.6 μg/ mL , which was better than that of ningnanmycin (175.6 μg/ mL ). The results of microscale thermophoresis ( MST ) demonstrated that S3 and S13 exhibited strong binding affinity to tobacco mosaic virus capsid protein ( TMV ‐ CP ), with Kd values of 0.0013 μM and 0.5397 μM , respectively. These values were significantly lower than that of ningnanmycin (Kd = 0.6509 μM ). The molecular docking results showed that the hydrogen bonds between S3 and the key amino acid residues of TMV ‐ CP had shorter bond lengths and were more tightly bound than those of ningnanmycin.