Ein einfacher Weg zu D ‐Apio‐β‐ D ‐furanosyl‐ und 2′‐Desoxyapio‐β‐ D ‐furanosylnucleosiden

A Convenient Route to D‐Apio‐β‐ D ‐furanosyl‐ and 2′‐Deoxyapio‐β‐ D ‐furanosyl Nucleosides 2,3‐ O ‐Isopropylidene‐ D ‐apio‐β‐ D ‐furanose ( 1 ), available in 40% overall yield by modified literature procedures, is acylated regioselectively to the new 3′‐ O ‐benzoyl‐derivative 2 . This is converted to the anomeric triacetates 4 (β‐4; α‐4 = 1.8:1) by cleavage of the isopropylidene protecting group from 2 followed by peracetylation. Reaction of compounds 4 with silylated nucleobases and subsequent deprotection gives the D‐apio‐β‐ D ‐furanosyl nucleosides 8–10 in good yields. Regioselective hydrazinolysis of the protected nucleosides 5 and 6 affords the 2′‐hydroxy‐derivatives 11 and 12 , respectively, which are converted to the 2′‐deoxyapio‐β‐ D ‐furanosyl nucleosides 17 and 18 , respectively, via deoxygenation of the corresponding thionocarbonates 13 and 14 with tris(trimethylsilyl)silane and subsequent deprotection. The 2′‐deoxyapio‐β‐ D ‐furanosyl cytosine 20 is prepared from the 2′‐deoxyapio‐β‐ D ‐furanosyl uracil derivative 16 .