Synthesis and biological activities of some quinolinone and dihydroquinolinone p38 MAP kinase inhibitors are reported. Modifications to the dihydroquinolinone pharmacophore revealed that dihydroquinolinone may be replaced with a quinolinone pharmacophore and lead to enhanced p38 inhibitory activity. From a study of C-7 substitutions by amino acid side chains, a very potent series of compounds in the p38 enzyme assays was identified. Translation of the in vitro activity into reasonable whole blood activity can be improved in this series of compounds by judicious modification of the physical properties at appropriate regions of the lead.

Development for a class of potent 3,4-dihydropyrido(3,2-d)pyrimidone inhibitors of p38a MAP kinase is described. Modification of N-1 aryl and C-6 arylsulfide in 3,4-dihydropyrido(3,2-d)pyrimidone analogues for the interaction with the hydrophobic pockets in p38 active site is also discussed.

Imidazo[1,2-a]pyridyl N-arylpyridazinones were hybridized from the classic pyridinylimidazoles and the more recent dual hydrogen bond acceptors, resulting in a new structural class of selective p38 MAP kinase inhibitors.

The development of potent, orally bioavailable (in rat) and selective dihydroquinazolinone inhibitors of p38alpha MAP kinase is described. These analogues are hybrids of a pyridinylimidazole p38alpha inhibitor reported by Merck Research Laboratories and VX-745. Optimization of the C-5 phenyl and the C-7 piperidinyl substituents led to the identification of 15i which gave excellent suppression of TNF-alpha production in LPS-stimulated whole blood (IC(50)=10nM) and good oral exposure in rats (F=68%, AUCn PO=0.58 microM h).

A new class of p38 antagonists based on 3,4-dihydropyrido[3,2,-d]pyrimidine scaffold has been developed. These inhibitors exhibit unprecedented selectivity towards p38 over other very closely related kinases. Compounds 25, 33, and 34 were identified as benchmark analogues for follow-up studies. They show good potency for enzyme inhibition and excellent functional activity.

PDB ID : 1M7Q Title : Crystal structure of p38 MAP kinase in complex with a dihydroquinazolinone inhibitor Authors : Stelmach, J.E.; Liu, L.; Patel, S.B.; Pivnichny, J.V.; Scapin, G.; Singh, S.; Hop, C.E.C.A.; Wang, Z.; Cameron, P.M.; Nichols, E.A.; O’Keefe, S.J.; O’Neill, E.A.; Schmatz, D.M.; Schwartz, C.D.; Thompson, C.M.; Zaller, D.M.; Doherty, J.B. Deposited on : 2002-07-22 Resolution : 2.40 Å(reported)

Trisubstituted pyridazines were synthesized and evaluated as in vitro inhibitors of p38MAPK. The most active isomers were those possessing an aryl group alpha and a heteroaryl group beta relative to the nitrogen atom in the 2-position of the central pyridazine. Additionally, substitution in the 6-position of the central pyridazine with a variety of dialkylamino substituents afforded a set of inhibitors having good (p38 IC50 1-20 nM) in vitro activity.

Major histocompatabilty (MHC) proteins rely heavily on peptide backbone recognition for ligation. Nonetheless, modifications to the polyamide backbone of a tetrapeptide ligand can be made without abrogating binding.

Tetrapeptide derived major histocompatability (MHC) II ligands have been developed that contain no unadulterated peptide bonds. These are the ‘least peptidic’ ligands for any MHC protein yet reported.

Comparison of SAR for a tetrapeptide inhibitor of MHC class II with existing information endorses a binding mode consistent with naturally loaded full length peptides.