Novel antifolates with a 6-5 fused ring system, 6, 7-dihydrocyclopenta [dlpyrimidine,(3a, b and 4a, b) were synthesized on the basis of combined modification of the heterocycle and bridge regions of the folate molecule. The synthetic method involves (1) synthesis of key intermediates of tert-butyl 4-[w-(2-substituted-3-oxocyclopentanyl) alkyll benzoates (8a, b and 9a, b) by a carbon-carbon radical coupling of tert-butyl4-(o-iodoalkyl) benzoates (7a, ...
