New Approach to the Synthesis of N7-Arylguanines and N7-Aryladenines

The copper-mediated arylation of 7-methylpyrimido[1,2-a]-purin-10(3H)-one (1) in dichloromethane or of N-2-(dimethylamino)methyleneguanine (2) in methanol in the presence of TMEDA as a base/ligand led to the preferential formation of 1-aryl-7-methylprimido[1,2-a]purin-10(3H)-ones (4) and 7-aryl-N-2-(dimethylamino)methyleneguanines (7), respectively. These compounds can be easily hydrolysed to the corresponding 7-arylguanines. Similar arylation of N-6-(dimethylamino)methyleneadenine (15) in the presence of o-phen-anthroline instead of TMEDA afforded mainly 7-aryladenines after hydrolysis. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)