7-Functionalized 7-deazapurine β- d and β- l-ribonucleosides related to tubercidin and 7-deazainosine: glycosylation of pyrrolo[2,3- d]pyrimidines with 1- O-acetyl-2,3,5-tri- O-benzoyl-β- d or β- l-ribofuranose

Abstract

Several 7-functionalized 7-deazapurine ribonucleosides were prepared. Glycosylation of 7-halogenated 6-chloro-7-deazapurines with 1- O-acetyl-2,3,5-tri- O-benzoyl-β- d-ribofuranose or 1- O-acetyl-2,3,5-tri- O-benzoyl-β- l-ribofuranose gave the protected β- d-nucleosides 8c– e (53–62%) and the β- l-nucleosides 9b– e (57–72%), which were transformed to 7-halogenated 7-deazapurine ribonucleosides related to tubercidin and 7-deazainosine. 7-Alkynyl derivatives ( 1f, g) and ( 2f, g) were obtained from the 7-iodo nucleosides 1e and 2e employing the palladium-catalyzed Sonogashira cross-coupling reaction. Within the series of 7-deazaadenosine (tubercidin) analogues and 7-deazainosine derivatives physical data such as p K a values, chromatographic mobilities, 13C NMR chemical shifts were determined and correlated to each other.