Synthesis of carbon-11-labeled casimiroin analogues as new potential PET agents for imaging of quinone reductase 2 and aromatase expression in breast cancer.

Carbon-11-labeled casimiroin analogues were first designed and synthesized as new potential PET agents for imaging of quinone reductase (QR) 2 and aromatase expression in breast cancer. [(11)C]casimiroin (6-[(11)C]methoxy-9-methyl-[1,3]dioxolo[4,5-h]quinolin-8(9H)-one, [(11)C]11) and its carbon-11-labeled analogues 5,6,8-trimethoxy-1-[(11)C]methyl-4-methylquinolin-2(1H)-one ([(11)C]17), 8-methoxy-1-[(11)C]methyl-4-methylquinolin-2(1H)-one ([(11)C]21a), 6,8-dimethoxy-1-[(11)C]methyl-4-methylquinolin-2(1H)-one ([(11)C]21b), and 5,8-dimethoxy-1-[(11)C]methyl-4-methylquinolin-2(1H)-one ([(11)C]21c), were prepared from their corresponding precursors with [(11)C]methyl triflate ([(11)C]CH(3)OTf) under basic conditions (NaH) through either O- or N-[(11)C]methylation and isolated by semi-preparative HPLC method in 40-50% radiochemical yields decay corrected to end of bombardment (EOB), based on [(11)C]CO(2), and 111-185GBq/mumol specific activity at the end of synthesis (EOS).