Syntheses of C- and N-nucleosides from 1-aza-2-azoniaallene and 1,3-diaza-2-azoniaallene salts

Abstract

C-Nucleosides are prepared by cycloaddition of 1-aza-2-azoniaallene salts 2 and 1,3-diaza-2-azoniaallene salts 5 to the triple bonds of a glycosylalkyne and of glycosyl cyanides. Thus, the glucosylalkyne 7 reacts with salts 5 to give the 4-glucosyl-1,2,3-triazolium salt 8. From the galactosyl cyanide 9, the ribofuranosyl cyanide 13, and several 1-aza-2-azoniaallene salts 2 the glycosyl-1,2,4-triazoles 11, 15, 17 are obtained. Deacylation affords the free C-nucleosides 12, 16, 18. Cycloaddition to the CS double bond of the glucosyl isothiocyanate 19 furnishes glucosylimino-1,3,4-thiaziazoles 20–22. A new method for the preparation of the isothiocyanate 19 is described.