Table 1. Cell-Based Readthrough Activity of Derivative 13a–y.

compd	R	readthrough activityab
G418 (2)	nac	7.99 ± 0.14
(+)-negamycin (4)	nac	2.25 ± 0.17
TCP-112 (7)	H	4.26 ± 0.06
13a	l-Leu	4.94 ± 0.18
13b	d-Leu	1.46 ± 0.09
13c	l-N(Me)-Leu	2.45 ± 0.22
13d	4-methylpentanoyl	2.82 ± 0.65
13e	Gly	2.74 ± 0.13
13f	l-Ala	2.40 ± 0.05
13g	l-Ser	1.48 ± 0.11
13h	l-Dap	3.02 ± 0.92
13i	l-Dab	3.25 ± 0.14
13j	l-Orn	2.96 ± 0.40
13k	l-Lys	2.49 ± 0.16
13l	l-Asp	1.96 ± 0.20
13m	l-Glu	1.80 ± 0.18
13n	l-Asn	2.21 ± 0.13
13o	l-Gln	1.62 ± 0.12
13p	l-Tyr	2.59 ± 0.13
13q	l-Phe	2.99 ± 0.35
13r	l-Val	2.00 ± 0.09
13s	l-Ile	1.83 ± 0.08
13t	l-Cha	5.87 ± 0.39
13u	l-Nle	4.21 ± 0.65
13v	l-Ahp (2)	3.40 ± 0.31
13w	l-Anon (2)	7.97 ± 0.47
13x (TCP-1109)	l-Aund (2)	15.96 ± 1.04
13y	l-α-aminotridecanoic acid	ndd

^aIn vitro readthrough activity in COS-7 cells against TGA-type PTC originally derived from nonsense mutation seen in DMD. A dual reporter plasmid encoding β-galactosidase and luciferase genes that were connected with a TGA-containing nucleotide sequence was used. The values are ratios relative to a control (D-MEM). Compounds were evaluated at a concentration of 200 μM.

^bCell-based readthrough activity (ratio) relative to TCP-112 (7) (= 4.26) in COS-7 cells.¹⁹ Compounds were evaluated at a concentration of 200 μM. Values are the mean ± SD (n = 3)

^cna: Not applicable.

^dnd: Not detected.