Synthesis of β-D-ribo- and 2′-deoxy-β-D-ribofuranosyl derivatives of 6-aminopyrazolo[4,3-<i>c</i>]pyridin-4(5<i>H</i>)-one by a ring closure of pyrazole nucleoside precursors
作者:Pranab K. Gupta、N. Kent Dalley、Roland K. Robins、Ganapathi R. Revankar
DOI:10.1002/jhet.5570230112
日期:1986.1
and 17, respectively). Ring closure of 15 and 17 in the presence of sodium carbonate gave 5 and 22, respectively. By contrast, glycosylation of the sodium salt of 6 with 2,3,5-tri-O-benzoyl-D-ribofuranosyl bromide (11) or the persilylated 6 with 1-O-acetyl-2,3,5-tri-O-benzoyl-β-D-ribofuranose gave mainly the N-2 glycosylated derivative 13, which on ammonolysis and ring closure furnished 18. Phosphorylation
6-氨基-1-(2-脱氧-β-D-氨基-呋喃呋喃糖基)吡唑并[4,3 - c ]吡啶-4(5 H)-一(5)以及2-(β-D-合成了6-氨基吡唑并[4,3 - c ]吡啶-4(5 H)-一(分别为18和22)的核糖呋喃糖基)-和2-(2-脱氧-β-D-核呋喃糖基)-衍生物。吡唑核苷前体的碱催化的闭环反应。甲基3(5)-cyanomethylpyrazole -4-羧酸乙酯(的钠盐的糖基化6与1-氯-2-脱氧-3,5-二- )ø - p甲苯甲酰-α-D-赤-pentofuranose(8)提供了相应的N-1和N-2糖基衍生物(分别为9和10)。用甲醇钠对9和10进行脱苯甲酰化,分别得到去保护的核苷14和16。14和16的进一步氨解得到5(或3)-氰基甲基-1-(2-脱氧-β-D-赤型-五呋喃糖基)吡唑-4-羧酰胺(分别为15和17)。在碳酸钠存在下15和17的闭环反应得到5和22, 分别。相比之下,钠盐的糖基化6与2