1. Cancer Research UK Drug Discovery Unit, Newcastle University Centre for Cancer, Chemistry, School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle upon Tyne NE1 7RU, UK
2. Organic Chemistry Group, College of Pharmacy, Naval Medical University, Shanghai, 200433, P. R. China
3. Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Manchester M13 9PT, UK