Table 1. Activity of oxazole and oxadiazole analogs of the BTD series against M. tuberculosis and Vero cell line.

Compound	R-group	MIC (µM)a	TC50 (µM)b	SIc
3a		3.1 ± 0.07	0.1 ± 0	0.03
3b		8.2 ± 0.6	0.2 ± 0	0.02
3c		5.7 ± 2.9	0.2 ± 0.07	0.04
3d		7.2 ± 0.3	0.3 ± 0.3	0.04
3e		3.9 ± 1.7	0.3 ± 0.2	0.08

Notes.

^aMIC is the minimum concentration required to inhibit growth of M. tuberculosis completely in liquid culture (Ollinger et al., 2013). MICs of active compounds are the average of two independent experiments ± standard deviation.

^bTC₅₀ is the concentration required to inhibit growth of Vero cells by 50%. TC₅₀ is the average of two runs ± standard deviation.

^cSI is the selectivity index. Selectivity index is calculated as MIC/TC₅₀.

For comparison, MIC of rifampicin is 0.003 µM and isoniazid is 0.2 µM (Ollinger et al., 2013).