Pyrrolo[2,3-d]pyrimidine beta-L-nucleosides containing 7-deazaadenine, 2-amino-7-deazaadenine, 7-deazaguanine, 7-deazaisoguanine, and 7-deazaxanthine

Abstract

The synthesis and properties of 7-deazapurine beta-L-nucleosides are described. The stereoselective glycosylation of the anions of 2-amino-6-chloro-7-deazapurines 9a, 9b or 6-chloro-7- deazapurines 13a, 13d with 3,5-di-O-(4-methylbenzoyl)-2-deoxy-alpha-L-erythro-pentofuranosyl chloride ( 8) furnished the beta-L-2'-deoxyribonucleosides 1 - 4. The synthesis of beta-L-ribonucleosides 5 - 7 used the Silyl - Hilbert - Johnson reaction (TMSOTf/BSA/MeCN) performed under Vorbruggen conditions for the glycosylation of 7-halogenated 6-chloro-2-pivalamido-7-deazapurines 17b - 17d with 1-O-acetyl-2,3,5-tri-O-benzoyl-L-ribofuranose ( 16). Single-crystal X-ray analyses were performed and CD spectra were measured to assign the configuration. The antiviral activity against selected DNA and RNA viruses is reported.