Azine-hydrazone Tautomerism of Thiazolylazo Pyridine Compound: Synthesis, Structural Determination, and Biological Activities

Thiazolation of phenylthiosemicarbazone to access new thiazoles: anticancer activity and molecular docking

Aim: Novel thiazole hybrids were synthesized via thiazolation of 4-phenylthiosemicarbazone (4). Materials & methods: The anticancer activity against the NCI 60 cancer cell line panel. Results: Methyl 2-(2-((1-(naphthalen-2-yl)ethylidene)hydrazineylidene)-4-oxo-3-phenylthiazolidin-5-ylidene)acetate (6a) showed significant anticancer activity at 10 μM with a mean growth inhibition (GI) of 51.18%. It showed the highest cytotoxic activity against the ovarian cancer OVCAR-4 with an IC50 of 1.569 ± 0.06 μM. Compound 6a inhibited PI3Kα with IC50 = 0.225 ± 0.01 μM. Moreover, compound 6a revealed a decrease of Akt and mTOR phosphorylation in OVCAR-4 cells. In addition, antibacterial activity showed that compounds 11 and 12 were the most active against Staphylococcus aureus. Conclusion: Compound 6a is a promising molecule that could be a lead candidate for further studies.

15N Solid-State NMR as Bright Eyes to See the Isomerization of the Azo Bond: Revision of Tris(β-hydroxyl-azo)-benzene to Tris(β-keto-hydrazo)-cyclohexane in Porous Organic Polymers

Porous organic polymers (POPs) have aroused great and wide attention from the materials community, while the identification of their precise structures is still very challenging. The well-defined structures are of great importance in understanding the relationship between the structure and function of the polymer materials, though they are sometimes ignored and do not receive enough attention. In this letter, an efficient ¹⁵N labeling technique and ¹⁵N solid-state NMR (¹⁵N-SSNMR) were combined to obtain strong evidence for the presence of the azo bond and keto-hydrazone structure in the solid state. Thus, the structure of tris(β-hydroxyl-azo)-benzene in previously proposed hydroxylazobenzene polymers was revised to tris(β-keto-hydrazo)-cyclohexane in TKH-POPs for the first time. In contrast, similar tautomerization did not occur in the azo coupling polymerization of 1,3,5-triaminobenzene and diazonium salts, i.e., tris(β-amino-azo)-benzene remained in Azo-POPs. This work will open up a window to develop innovative porous organic polymers more efficiently with the aid of ¹⁵N-SSNMR.