Synthesis and Molecular Modeling Studies and In silico Anthelmintic Activity of N-(benzo[d]thiazol-2-yl)-3- Chloro-6-Nitrobenzo[b]thiophene- 2-Carboxamide Derivatives

Abstract

Helminthiasis is a noteworthy health problem with increased morbidity. In this manuscript, we developed a series of N-(benzo[d]thiazol-2-yl)-3-chloro-6-nitrobenzo[b]thiophene-2-carboxamide derivatives (3a-f) and evaluated against Pheretima posthuma and Perionyx excavates helminths. The compounds 3a-f were synthesized by reaction of 3-chloro-6-nitrobenzo[b]thiophene-2-carbonyl chloride (1) and appropriate benzo[d]thiazol-2-amines (2a-f) presence of pyridine. A compound 1 was synthesized by reaction of 4-nitro-cinnamic acid reacts with thionyl chloride in the presence of pyridine and chlorobenzene. Results showed that molecule 3c observed with maximum anthelmintic against P. excavates and P. posthuma with mean paralyzing time of 13.15 min and 17.39 min and mean death time of 16.17 min and 20.14 min, respectively. Molecular docking against 3VRA receptor showed that molecule 3c showed maximum dock score of -7.3 kcal/mol and reference standard albendazole with dock score of -5.5 kcal/mol. Molecular dynamic simulation data reflected the stable ligand-receptor interaction. As per Molecular Mechanics Poisson-Boltzmann Surface Area analysis, maximum free binding energy of -31.224 kJ/mol showed by 3c and ARG 76 was the most contributed residue. Density functional theory calculation data confirmed that most of the molecules were soft molecules with electrophilic nature. Molecular electrostatic potential data of 3c showed that terminal nitro group, ketone group, -COO group of ester were responsible for electrophilic attack and benzo[b]thiophne and -NH groups were responsible for nucleophilic attack. The activity profile of the synthesized molecules against helminthes was 3c >3e >3d >3f >3b >3a.. KEYWORDS :Molecular docking, Molecular dynamic simulation, Molecular mechanics poisson-boltzmann surface area, Density functional theory, Anthelmintic activity.