Investigation of novel bis-thiadiazole bearing schiff base derivatives as effective inhibitors of thymidine phosphorylase: Synthesis, in vitro bioactivity and molecular docking study.

Thymidine phosphorylase (TP) is an angiogenic enzyme. It is crucial for the development, invasion and metastasis of tumors as well as angiogenesis. In our current research, we examine how structurally changing bis-thiadiazole bearing bis-schiff bases affects their ability to inhibit TP. Through the oxidative cyclization of pyridine-based bis-thiosemicarbazone with iodine, a series of fourteen analogs of bis-thiadiazole-based bis-imines with pyridine moiety were developed. Newly synthesized scaffolds were assessed in vitro for their thymidine phosphorylase inhibitory potential and showed moderate to good inhibition profile. Eleven scaffolds such as 4a-4d,4f-4 h and 4j-4 m were discovered to be more effective than standard drug at inhibiting the thymidine phosphorylase enzyme with IC50 values of 1.16 ± 1.20, 1.77 ± 1.10, 2.48 ± 1.30, 12.54 ± 1.60, 14.63 ± 1.70, 15.53 ± 1.80, 17.47 ± 1.70, 18.98 ± 1.70, 19.53 ± 1.50, 22.73 ± 2.40 and 24.87 ± 2.80 respectively, while remaining three analogs such as 4n, 4i and 4ewere found to be more potent, but they were less potent than the standard drug. All analogs underwent SAR studies based on the pattern of substitutions around the aryl part of the bis-thiadiazole skeleton. The most active analogs in the synthesized series were then molecular docking study performed to investigate their interactions of active part of enzyme. The results showed that remarkable interactions were exhibited by these analogs with the targeted enzymes active sites. Furthermore, to confirm the structure of synthesized analogs by employing spectroscopic tools such as HREI-MS and NMR.

Molecular iodine-promoted oxidative cyclization for the synthesis of 1,3,4-thiadiazole-fused- [1,2,4]-thiadiazole incorporating 1,4-benzodioxine moiety as potent inhibitors of α-amylase and α-glucosidase: In vitro and in silico study.

Twenty-five analogs were synthesized based on 1,3,4-thiadiazole-fused-[1,2,4]-thiadiazole incorporating 1,4-benzodioxine moiety (1-25) and then tested for the antidiabetic profile. The entire afforded derivatives showed varied inhibition profiles ranging between 0.70 ± 0.01 and 30.80 ± 0.80 µM (against α-amylase) in comparison to standard acarbose (12.80 ± 0.10 µM). Similarly, synthetics analogs also displayed a varied range of α-glucosidase activity ranging from 0.80 ± 0.01 µM to IC50 = 29.70 ± 0.40 µM (against α-glucosidase) as compared to standard acarbose (IC50 = 12.90 ± 0.10 µM). Among synthesized analogs, compound 22 showed excellent potency due to the presence of di-hydroxy substitutions at the 2,3-position of the aryl ring. For all analogs, the structure-activity relationship was carried out based on the pattern of substitutions around the aryl ring, and further, the potent analogs were subjected to a molecular docking study to analyze how active residues of targeted enzymes interact with active parts of newly prepared analogs. The result obtained shows that these compounds furnish several key interactions with enzyme active sites and, hence, enhanced their enzymatic activities.