New C-2 symmetrical and semisymmetrical substituted imidazolium ribonucleoside. Imidazolic nucleosides analogues

New C-2 symmetrical imidazolium ribonucleosides have been synthesized. The silyl Hilbert Johnson-Vorbrugen method was used. Subsequent coupling of trimethylsilylimidazole with the peracylated D-ribofuranose 1, followed by removal of the protecting groups, afforded 1,3-bis(beta-D-ribofuranosyl)imidazolium 7 and 1-(beta-D-ribofuranosyl)imidazole 8. In a similar synthetic sequence, 4(5)-substituted bis-ribofuranosylimidazolium 14 was also prepared, For the selective preparation of the monoglycosylated imidazole 15, the classical method starting from 2,3,5-tri-O-benzoyl-D-ribofuranosyl bromide in acetonitrile and using Hg(CN)2 was employed. These new base modified nucleosides were devoid of activity against HIV and cytotoxicity. Copyright (C) 1996 Elsevier Science Ltd.