Synthesis and evaluation of in vitro antimycobacterial activity of some 5-(5-nitro-2-thienyl)-2-(piperazinyl, piperidinyl and morpholinyl)-1,3,4-thiadiazole derivatives. 
A new series of 5-(5-nitro-2-thienyl)-2-(piperazinyl, piperidinyl and morpholinyl)-1,3,4-thiadiazole derivatives(5a-g) have been synthesized and evaluated against Mycobacterium tuberculosis H37Rv as apart of TAACF TB screening program under direction of the US National Institute of Health, NIAID division.  Primary screening was conducted at the single concentration, 6.25 mg/ml against Mycobacterium tuberculosis H37Rv (ATCC 27294) in BACTEC 12B medium using a broth microdilution assay, the Microplate Alamar Blue Assay (MABA).  The minimum inhibitory concentration (MIC) determined for compounds demonstrating 90% growth inhibition in the primary screening.  The tested compounds showed a varying degree of inhibitory activity (Inhibition = 0-100%).  The most active compounds were 4-methyl and 4-benzoylpiperaxinyl analogues(5b and 5g) with the same MIC value of 3.13 micrograms/ml.