Novel asymmetrical azines appending 1,3,4-thiadiazole sulfonamide: synthesis, molecular structure analyses, <i>in silico</i> ADME, and cytotoxic effect

Abstract

Toward finding potential and novel anticancer agents, we designed and prepared novel differently substituted unsymmetrical azine-modified thiadiazole sulfonamide derivatives using the "combi-targeting approach". An efficient procedure for synthesizing the designed compounds starts with 5-acetyl-3-<i>N</i>-(4-sulfamoylphenyl)-2-imino-1,3,4-thiadi-azoline 4. The <i>E</i>/<i>Z</i> configuration for compound 5 was investigated based on spectral analysis combined with quantum mechanical calculation applying the DFT-B3LYP method and 6-31G(d) basis set. The computational results found that the <i>E</i> isomer was energetically more favorable than the <i>Z</i> isomer by 2.21 kcal mol^-1. Moreover, ¹H and ¹³C chemical shifts for the <i>E</i> and <i>Z</i> isomers in DMSO were predicted using the GIAO-B3LYP/6-31G(d) computations and IEF-PCM solvation model. The computed chemical shifts for both isomers are consistent with those observed experimentally, indicating that they exist in the solution phase. Moreover, the <i>E</i>/<i>Z</i> configuration for the synthesized azines 7a-c, 9, 11, 13, 15a and 15b was also studied theoretically using the DFT-B3LYP/6-31G(d) calculations. <i>In silico</i> prediction for the biological activities was reported regarding the HOMO-LUMO energy gaps and molecular reactivity descriptors besides the ADMT/drug-likeness properties. The cytotoxic effect of the synthesized compounds has been assayed <i>via</i> the determination of their IC₅₀.