Intramolecular direct C-H arylation approach to fused purines. Synthesis of purino[8,9-f]phenanthridines and 5,6-dihydropurino[8,9-a]isoquinolines.

Igor Cerna, Radek Pohl, Blanka Klepetárová, Michal Hocek

文献索引：J. Org. Chem. 75(7) , 2302-8, (2010)

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摘要

Intramolecular C-H arylations were employed as a key step in the synthesis of hitherto unknown fused purine systems: 13-substituted purino[8,9-f]phenanthridines and 11-substituted 5,6-dihydropurino[8,9-a]isoquinolines. The purino[8,9-f]phenanthridines were prepared in moderate yields by double C-H arylations of 9-phenylpurines with 1,2-diiodobenzene or, more efficiently, by consecutive Suzuki coupling of 9-(2-bromophenyl)purines with 2-bromophenylboronic acid followed by intramolecular C-H arylation. 5,6-Dihydropurino[8,9-a]isoquinolines were prepared in quantitative yields by intramolecular C-H arylations of 9-(2-chlorophenethyl)purines.