Synthesis, characterization, and in silico studies on new series of hydrazide-hydrazones for potential anti-tubercular agents.

BACKGROUND/OBJECTIVES: The analogues of nitrogen particularly compounds containing two nitrogen atoms like Quinazolines, Imidazoles and hydrazides are important type of precursors to the most drugs. Moreover, compounds with two nitrogen atoms showed versatile biological activities such as anti-tubercular activity, antibacterial (gram + ve and gram-ve), anti-HIV, antifungal, anticancer, antibiotic, etc activities. So, based on the literature profile of the Quinazolines, Imidazoles, and hydrazides it is proposed to design a novel hybrid moiety by the combination of above three moieties for possible antitubercular agents.

METHODS: A string of new Imidazole-benzohydrazide derivatives (6a-n) were synthesized starting from a chloro-substituted quinazolin(1) in three consecutive steps. All the 14 synthesized compounds were well characterized by 1H NMR, 13C NMR and Mass spectral data and then screened for their anti-tuberculosis activity. Further, In silico studies were carried out for uncovering the probable structure-based mechanism of action.

RESULTS AND CONCLUSIONS: Among the synthesized compounds, compound 6k with m-bromo, m-methoxy and p-hydoxy substitutions has given highest MIC of 7.81 μg/mL and compounds 6a(p-hydroxy), 6d(o-,m-,p-hydroxy), and 6j (m- and p-hydroxy) were also showed good sensitivity up to 15.62 μg/mL (6i, 6b, 6j). Further, the antitubercular activity was compared with the standards Para-aminosalicilic acid and Rifampicin. In silico studies has given a good correlation of in vitro activity with better binding energy and interaction profile of 6i compound along with 6j and 6d and they might hold the potential to be anti-mycobacterial hit compounds which requires structural optimization to refine the ADME properties in the further exploratory studies.