Cancer is one of the leading causes of death. There have been many investigations into therapeutic ways to prevent and reverse cancerous growth. We report a new approach in this thesis, which is to investigate the functions of Vitamin B1 (thiamine) in cancerous cells and their regulation. A number of thiamine analogs were synthesized to carry out the structure-activity relationship (SAR) studies with two transporters THTR1 and THTR2. Initial results show that the modifications of thiazole reduced the uptake of thiamine.