A novel dipeptide coupled with pyrazine-oxadiazole derivative as a potential antitubercular agent: Synthesis, radioiodination and bioevaluation.

Tuberculosis (TB) is a disease caused by Mycobacterium and usually attack the lung. Synthesis of new dipeptide derivatives attached to antitubercular active heterocyclic rings like pyrazine and 1,3,4-oxadiazole called ethyl 2-(2-(5-((pyrazin-2-ylamino) methyl)-1,3,4-oxadiazol-2-ylthio) acetamido) acetamido)-3-(4-hydroxyphenyl) propanoate (EPOGTP) and iodinated EPOGTP are reported. The compounds have been characterized by mass, FT-IR and 1H NMR spectroscopy. Their in vitro investigation against Mycobacterium tuberculosis cell line indicated good IC50value of 210 μg/ml for EPOGTP and 86 μg/ml for iodo-EPOGTP. For study the biodisriution, the direct radioiodination of EPOGTP with iodine-131 using mild oxidizing agent, N-Bromosuccinimide (NBS), was performed and optimized for obtaining the maximum radiochemical purity (97.3 ± 0.47%). Then, the in vivo biodistribution in healthy mice showed good accumulation of radioiodinated EPOGTP in lung of about 41.83 ± 0.23% (the percentage of injected dose per gram of organ) at 15 min post-injection. As a conclusion, the synthetized dipeptide and its iodinated derivative could be further evaluated as a potential antitubercular agents.