Design and synthesis of 4-(2, 3-dihydro-1H-benzo[d]pyrrolo[1, 2-a]imidazol-7-yl)-N-(5-(piperazin-1-ylmethyl)pyridine-2-yl)pyrimidin-2-amine as a highly potent and selective cyclin-dependent kinases 4 and 6 inhibitors and the discovery of structure-activity relationships. Issue 5 (1st March 2018)