RATIONAL DESIGN, SYNTHESIS AND SPECTROSCOPIC CHARACTERIZATION OF NOVEL IMINE-LINKED THIADIAZOLE DERIVATIVES AND THEIR IN VITRO ANTIBACTERIAL EVALUATION

Hridesh Singh Chauhan*, Dr. Manish Thimmaraju, Dr. Jitendra Kumar Malik, Dr. Vivek Gupta, Gyan Singh, Utkarsh Sharma

ABSTRACT

A series of novel imine-linked 1,3,4-thiadiazole derivatives were rationally designed and synthesized via Schiff
base condensation to explore their antibacterial potential. The synthetic strategy aimed to integrate the
pharmacologically active thiadiazole nucleus with an azomethine (–CH=N–) linkage to modulate electronic
properties and enhance biological activity. The synthesized compounds were characterized by FT-IR, ¹H NMR and
mass spectrometry. The analytical and spectral data confirmed the proposed structures and indicated satisfactory
purity of the compounds. In vitro antibacterial activity was evaluated against Gram-positive strains (Staphylococcus
aureus, Staphylococcus epidermidis, and Streptococcus mutans) and the Gram-negative strain (Escherichia coli)
using agar diffusion and broth micro-dilution methods. Ciprofloxacin was employed as the reference standard.
Among the synthesized derivatives, eight compounds exhibited significant antibacterial activity. Compounds TZ3
and TZ5 demonstrated the highest zones of inhibition and TZ5 and TZ10 shown lowest minimum inhibitory
concentration (MIC) values, indicating superior antibacterial efficacy within the series. Preliminary structure–
activity relationship analysis suggested that substituent variations significantly influenced antimicrobial potency.
These findings identify imine-linked thiadiazole derivatives, particularly TZ3, TZ5 and TZ10 as promising
antibacterial lead molecules for further optimization.

Keywords: 1,3,4-Thiadiazole; Schiff base synthesis; Antibacterial activity; MIC; Spectral characterization.