Table 4.

Oxadiazoles: Anti-HIV-1 Activity (EC₅₀) and Cytotoxicity (CC₅₀)

Compd	R1	R2	R3	R4	EC50a (µM)	CC50b (µM)
1	4-CH3	H	3′-OCH3	4′-OCH3	NA	61
2	H	H	H	H	NA	>100
3	4-Cl	H	H	H	NA	31
4	4-Cl	H	4′-Cl	H	NA	>100
5	4-Cl	H	5′-Cl	H	>10	32
6	2-Cl	H	2′-Cl	6′-Cl	NA	>100
7	3-Cl	H	2′-Cl	6′-Cl	4.3	71
8	4-Cl	H	2′-Cl	6′-Cl	0.82	20
9	4-Cl	2-Cl	2′-Cl	6′-Cl	2.4	45
10	4-Cl	3-Cl	2′-Cl	6′-Cl	0.31	>100
11	4-Cl	3-CH3	2′-Cl	6′-Cl	1.3	>100
12	4-CH2OCH3	H	2′-Cl	6′-Cl	4.3	100
13	4-CN	H	2′-Cl	6′-Cl	0.13	40
14	4-CN	H	2′-F	6′-F	0.23	90
d4T					1.4	>100
nevirapine					0.11	>10
efavirenz					0.002	>0.1

^aFor 50° protection in MT-2 cells; antiviral curves used triplicate samples at each concentration. NA for EC₅₀ > CC₅₀.

^bFor 50% inhibition of MT-2 cell growth; toxicity curves also used triplicate samples.