Table 2.

TSPO binding affinity of N,N-dialkylindolylglyoxylamide derivatives I a–k, and 17–31.

Ia–k, 17–31
Ligand	R1	R2	R3	R4	R5	Ki (nM)a
1						9.30 ± 0.50
3						23.0 ± 3.0
4						0.5–7
Ia b	nPr	nPr	H	H	H	12.2 ± 1.0
Ib b	nBu	nBu	H	H	H	7.50 ± 0.70
Ic b	nHex	nHex	H	H	H	1.40 ± 0.20
Id c	Et	nBu	H	H	H	12.6 ± 1.0
Ie c	Et	Bn	H	H	H	11.0 ± 1.0
If c	Me	nBu	H	H	H	53.3 ± 4.0
Ig c	Me	nPen	H	H	H	12.1 ± 1.0
17	Me	Bn	H	H	H	12.0 ± 1.0
Ih c	nPr	nPr	H	H	F	2.67 ± 0.48
Ii b	nPr	nPr	F	H	H	4.28 ± 0.32
Ij b	nHex	nHex	F	H	H	0.370 ± 0.13
18	Me	Bn	F	H	H	1.80 ± 0.10
Ik c	nPr	nPr	NO2	H	H	0.950 ± 0.10
19	nPr	nPr	H	Me	H	19.5 ± 1.5
20	nBu	nBu	H	Me	H	0.300 ± 0.050
21	nHex	nHex	H	Me	H	0.299 ± 0.050
22	Et	nBu	H	Me	H	60.2 ± 6.0
23	Et	Bn	H	Me	H	2.92 ± 0.30
24	Me	nBu	H	Me	H	190 ± 10
25	Me	nPen	H	Me	H	38.2 ± 4.0
26	Me	Bn	H	Me	H	20.9 ± 1.8
27	nPr	nPr	H	Me	F	23.7 ± 2.1
28	nPr	nPr	F	Me	H	19.8 ±2.0
29	nHex	nHex	F	Me	H	1.07±0.11
30	Me	Bn	F	Me	H	6.77 ± 0.50
31	nPr	nPr	NO2	Me	H	5.70 ± 0.45

^aThe concentration of tested compounds that inhibited [³H]1 binding to rat kidney mitochondrial membranes (IC₅₀) by 50% was determined with six concentration of the displacers, each performed in triplicate. K_i values are the mean ± SEM of three determination.

^bData taken from ref. 27.

^cData taken from ref. 28.