Table 1.

Anti-SARS-CoV-2 properties of the synthesized spiroindoles 6a‒l and standard references.

Compd.	IC50 (μM)	CC50 (μM)	Selectivity index (SI)
6a	88.61	73.07	0.82
6b	10.39	22.0	2.12
6c	85.84	126.0	1.47
6d	13.53	18.83	1.39
6e	340	9.834	0.03
6f	7.26	10.0	1.38
6g	8.88	20.33	2.29
6h	46.74	38.33	0.82
6i	35.21	87.01	2.47
6j	21.66	40.10	1.85
6k	106.1	49.92	0.47
6l	578.4	23.71	0.04
Favipiravir [65]	1382	5262	3.8
Hydroxychloroquine [61]	36.92	356.4	9.7
Chloroquine [61]	24.98	377.7	15.1

$$\mathrm{S}\mathrm{I}=\raisebox{1ex}{${CC}_{50}$}\!\left/ \!\raisebox{-1ex}{${IC}_{50}$}\right.$$