Oxidations Facilitated By Bis-Urea Benzophenone Macrocycles

Common industrial oxidants produce stoichiometric amounts of waste and, occasionally, dangerous byproducts. Singlet oxygen is a more environmentally friendly oxidant but produces a variety of products, so it is not used in industry. Benzophenone macrocycles employ singlet oxygen to oxidize guest molecules that are inside them, so certain products are favored due to the limited space. Also, some singlet oxygen reactions do not usually occur, such as the oxidation of gamma-butyrolactone. To synthesize the macrocycle, bromine groups were added to each of the methyl groups in 4, 4-dimethylbenzophenone and reacted with protected urea to form the protected macrocycle. The urea molecules were then removed to form the final macrocycle, which was purified through recrystallization. Thermogravimetric Analysis (TGA) was used to calculate the loading ratio of the guest molecule to macrocycle, with dimethyl sulfoxide (DMSO) and gamma-butyrolactone as guests. Benzophenone macrocycles were used to oxidize gamma-butyrolactone with ethyl acetate or tetrahydrofuran (THF) as solvents. Proton-Nuclear Magnetic Resonance (H1-NMR) revealed that the gamma-butyrolactone was oxidized using ethyl acetate. The oxidized compound was not the desired product and further analysis of this compound is needed to verify its structure. In future experiments, the concentration of the gamma-butyrolactone should to be lowered and the irradiation time should be lengthened.