Table 7.

Biological evaluation of selected analogues against C. difficile and direct PFOR inhibition.

Analogue[a]	MIC (μM)	PFOR Inhibition[c]
	C. difficile	[Drug] = 40 μM (%)
Nitazoxanide (1)	1.2	54 ± 7
42	6.0	68 ± 5b
19	0.8	55
8	3.3	85b
23	0.5	41.5 ± 5.5
41	1.4	33 ± 1
59	2.8	61 ± 13
53	5.9	54 ± 1
50	8.2	64 ± 6b
60	1.7	58 ± 2b
74	2.9	58.5 ± 3.5b
61	2.4	42b
76	1.5	56 ± 6b

^[a]R = H unless otherwise noted;

^bComplex pattern of inhibition with two different rates;

^[c]For PFOR inhibition assays, drug concentration was fixed at 40 μM which bench marks NTZ at ~50% inhibition.