Behavior of reaction mixtures under microwave conditions: Use of sodium salts in microwave-induced N-[18F]fluoroalkylations of aporphine and tetralin derivatives

In the present study, the authors have examined the behavior of reaction mixtures in a microwave field and the use of sodium salts to manipultate reaction rates. Three potential dopamine D2 agonists 2-[N-(3-[18F]fluoropropyl)-N-[(4-fluorophenyl)ethyl]amino]-5-methoxytetralin (2), 6-(2-[18F]fluoroethyl)-10,11-diacetylnoraporphine (4a), and 6-(3-[18F]fluoropropyl)-10,11-diacetylnoraporphine (4b) were synthesized in a commercial Miele M 686 microwave oven. the radiochemical yield based on [18F]fluoroalkyl iodide and corrected for decay was determined by HPLC analysis. The indentity of the labeled products was established by comparison with the HPLC elution profiles of reference material. The reference materials were identified by 1H NMR, 13C NMR, 19F NMR, and mass spectroscopy. Compounds 2, 4a, and 4b were also synthesized in a reaction medium heated on an oil bath for comparison with microwave treatment. 14 refs., 7 figs