Nucleoside analogues with a novel glycone based on the benzo[c]furan core

Routes to novel nucleoside analogues based on 1,3-dihydrobenzo[c]furan have been investigated. Thus 1-(1,3-dihydro-3-hydroxymethylbenzo[c]furan-1-yl)-thymine, an analogue of d4T, was obtained as two diastereoisomers. The cis compound (quasi beta-D/alpha-L stereochemistry) was obtained pure but the trans compound was only 90% pure. A purine analogue with a four atom spacer group between base and glycone was also prepared. The conformation of these constrained nucleosides was studied by molecular modelling.