Préparation des 2′-désoxy-5′- O-(2-hydroxyéthyl)adénosines par la méthode de fusion

Abstract

Alkaline elimination, followed by Ruff degradation of 6- O-(2-hydroxyethyl)-3- O-methyl- D-glucose, readily obtained by epoxide ring opening of 5,6-anhydro-1,2- O-isopropylidene-3- O-methyl-α- D-glucose with monosodium ethylene glycolate, gave a syrup containing almost 50% of 2-deoxy-5- O-(2-hydroxyethyl)- D- erythropentose. This crude product was acetylated and coupled directly by fusion to 6-benzamidopurine which, after deblocking, yielded 9-[2-deoxy-5- O-(2-hydroxyethyl)-α- D- erythro-pentofuranosyl]adenine and its β isomer, 2′-deoxy-5′- O-(2-hydroxyethyl)-adenosine. The n.m.r. spectra of some α-nucleosides in deuterium oxide solution have been compared and a similar pattern has been noted in the H-2′ region. Attempts at selective tosylation of methyl 2-deoxy- D- erythro-pentofuranoside gave low yields of the 5-sulfonate. Its structure was confirmed by conversion to the p-nitrophenyl ether, which was independently obtained by periodate oxidation of 3-deoxy-6- O- p-nitrophenyl- D- ribo-hexose, followed by glycosidation.