Tumor progression loci-2 (Tpl2) (Cot/MAP3K8) is a serine/threonine kinase in the 
MAP3K family directly upstream of MEK. Recent studies using Tpl2 knockout mice 
have indicated an important role for Tpl2 in the lipopolysaccharide (LPS) 
induced production of tumor necrosis factor alpha (TNF-alpha) and other 
proinflammatory cytokines involved in diseases such as rheumatoid arthritis. 
Initial 4-anilino-6-aminoquinoline-3-carbonitrile leads showed poor selectivity 
for Tpl2 over epidermal growth factor receptor (EGFR) kinase. Using molecular 
modeling and crystallographic data of the EGFR kinase domain with and without an 
EGFR kinase-specific 4-anilinoquinazoline inhibitor (erlotinib, Tarceva), we 
hypothesized that we could diminish the inhibition of EGFR kinase by 
substitution at the C-8 position of our 
4-anilino-6-aminoquinoline-3-carbonitrile leads. The 
8-substituted-4-anilino-6-aminoquinoline-3-carbonitriles were prepared from the 
appropriate 2-substituted 4-nitroanilines. Modifications to the C-6 and C-8 
positions led to the identification of compounds with increased inhibition of 
TNF-alpha release from LPS-stimulated rat and human blood, and these analogues 
were also highly selective for Tpl2 kinase over EGFR kinase. Further 
structure-activity based modifications led to the identification of 
8-bromo-4-(3-chloro-4-fluorophenylamino)-6-[(1-methyl-1H-imidazol-4-yl)methylamino]quinoline-3-carbonitrile, 
which demonstrated in vitro as well as in vivo efficacy in inhibition of 
LPS-induced TNF-alpha production.