I think its basicaly a stuff you want to do as your research project. I would write something like this :
compound XY was initialy prepared by prof.Z by unexpected side reacition. Since the XY showed interesting inhibitory activity against CDK2 there is a chance that derivatives with higher activity against such enzyme can be prepared. Due to structure similarity to X and Y already in clinical practice we might expect that substitution at position 1,2 and 5 are critical for the inhibitor activity so the project will initialy focus on preparing differently substitued compounds at positions 1,2 and 5 to determine SAR relationship. Furthermore, the mechanism of unexpected side reaction will be determined using various spectroscopic and computational methods and the conditions of this step will be optimized to improve the yield and purity of the product..
etc..
etc..
You need to write some introduction to the topic, briefly sumarizing the current state of the art and then propose what you want to do, why you want to do it and how you are going to do it. Maybe ask someone at your school to help you with that (PhD student maybe?)