Facile reductive cleavage of purine nucleosides to acyclonucleosides using diisobutylaluminium hydride (DIBAL): a new synthetic method for the preparation of 9-ribitylpurine derivatives.

Reaction of purine nucleosides, such as 2',3'-isopropylideneinosine (1a) and 2',3'-isopropylideneadenosine (1c), with diisobutylaluminum hydride (DIBAL) in dry tetrahydrofurane resulted in the formation of the corresponding 9-(2',3'-isopropylideneribity)purines (2) in good yields. Oxidation of the ribityl derivatives (2) with NalO4 and subsequent reduction with NaBH4 gave the corresponding 9-(2',3',4'-trihydroxybutyl)-purine derivatives (4) in high yields. Deprotection of compounds 2 and 4 in 80% acetic acid gave the corresponding 9-(2',3',4'-trihydroxybutyl)purines (5) and 9-ribitylpurines (6), respectively.