Table 22.

c-KIT enzymatic inhibitory activities of thiazolo[5,4-b]pyridine derivatives.

Compd.	R1	R2	IC50 (µM) a	Entry	R1	R2	IC50 (µM) a
imatinib	-	-	0.27	142p		-	5.72
sunitinib	-	-	0.14	142q		-	3.23
142a		-	inactive b	142r		-	0.14
142b		-	inactive b	142s		-	0.37
142c		-	inactive b	142t		-	1.25
142d		-	inactive b	142u		-	4.56
142e		-	inactive b	142v		-	0.39
142f		-	inactive b	142w		-	0.25
142g		-	inactive b	143a		cyclohexyl	1.51
142h		-	9.87	143b		phenyl	0.74
142i		-	inactive b	143c		methyl	0.1
142j		-	inactive b	143d		cyclohexyl	inactive b
142k		-	4.31	143e		methyl	0.88
142l		-	1.76	143f		methyl	3.63
142m		-	2.17	143g		methyl	0.18
142n		-	inactive b	143h		methyl	0.10
142o		-	5.03

^a Radiometric biochemical kinase assay results. ^b less than 50% inhibition at a concentration of 10 µM.