p38 MAP kinase inhibitors. Part 3: SAR on 3,4-dihydropyrimido[4,5-d]pyrimidin-2-ones and 3,4-dihydropyrido[4,3-d]pyrimidin-2-ones

p38 inhibitors based on 3,4-dihydropyrimido[4,5-d]pyrimidin-2-one and 3,4-dihydropyrido[4,3-d]pyrimidin-2-one platforms were synthesized and preliminary SAR explored. Among the pyrimido-pyrimidones the emergence of two sub-types of analogs—C7-amino-pyrimidines such as 24 and C7-amino-piperidines such as 42—characterized with good p38 inhibition and better off-target profiles in terms of ion channel activities was significant. Representative compound 54 in the pyrido-pyrimidone class was found to be equipotent with corresponding analog in the quinazolinone series.