Coupling of 4,6-dichloro-1H-imidazo[4,5-c]pyridine (2,6-dichloro-3-deaza-9H-purine) (1) with 1,2-O-di-acetyl-5-O-benzoyl-3-deoxy-β-D-ribofuranose (2), employing the acid-catalyzed fusion method, is reported (Scheme 1). The condensation reaction was regioselective and gave the three N1-glycosylation products 3 – 5, whereas no N3-nucleosides were detected. Treatment of 3 – 5 with methanolic ammonia afforded the corresponding deprotected nucleosides 6 – 8. Compounds 6 and 7 were assigned the structure of the β-D- and α-D-anomeric N1-(3′-deoxyribo)nucleosides, respectively. The third derivative 8 proved to be the α-D-anomer of a 3′-deoxyarabinonucleoside deriving from epimerization at C(2) of the sugar. The 2-chloro- and N6-substituted derivatives 9, 11, and 13 of 3′-deoxy-3-deazaadenosine (10) and of its α-D-anomer 12 can be obtained from these versatile synthons (Schemes 2 and 3).
Synthesis of New 3′-Deoxyribonucleosides Employing the Acid-Catalyzed Fusion Method
CAMAIONI, Emidio;
1998
Abstract
Coupling of 4,6-dichloro-1H-imidazo[4,5-c]pyridine (2,6-dichloro-3-deaza-9H-purine) (1) with 1,2-O-di-acetyl-5-O-benzoyl-3-deoxy-β-D-ribofuranose (2), employing the acid-catalyzed fusion method, is reported (Scheme 1). The condensation reaction was regioselective and gave the three N1-glycosylation products 3 – 5, whereas no N3-nucleosides were detected. Treatment of 3 – 5 with methanolic ammonia afforded the corresponding deprotected nucleosides 6 – 8. Compounds 6 and 7 were assigned the structure of the β-D- and α-D-anomeric N1-(3′-deoxyribo)nucleosides, respectively. The third derivative 8 proved to be the α-D-anomer of a 3′-deoxyarabinonucleoside deriving from epimerization at C(2) of the sugar. The 2-chloro- and N6-substituted derivatives 9, 11, and 13 of 3′-deoxy-3-deazaadenosine (10) and of its α-D-anomer 12 can be obtained from these versatile synthons (Schemes 2 and 3).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
