4-[6-[[6-(1-Butoxyvinyl)-8-cyclopentyl-5-methyl-7-oxo-7,8-dihydropyrido[2,3-d]pyrimidin-2-yl]amino]pyridin-3-yl]piperazine-1-carboxylic acid tert-butyl ester

4-[6-[[6-(1-Butoxyvinyl)-8-cyclopentyl-5-methyl-7-oxo-7,8-dihydropyrido[2,3-d]pyrimidin-2-yl]amino]pyridin-3-yl]piperazine-1-carboxylic acid tert-butyl ester