arbonyl-S-methylisothiocarbamoyl)amino]pyrazole-4-carboxylate (8). Ring closure of 8 under alkaline media furnished 6-amino-1-(2,3-O-isopropylidene-β-D-ribofuranosyl)-1H-pyrazolo[3,4-d]-1,3-oxazin-4-one (10), which on deisopropylidenation afforded 4 in good yield. 6-Amino-1-(β-D-ribofuranosyl)-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one (5) has also been synthesized from the AICA riboside congener 5-amino-1-(2
6-
氨基-1-(β-D-
呋喃呋喃糖基)-1 H-
吡唑并[3,4- d ] -1,3-恶嗪-4-酮(4),是一种由核苷抗生素
恶唑烷合成的等排体5-
氨基-1-(2,3 - O-异亚丙基-β-D-
呋喃呋喃糖基)
吡唑-4-羧酸乙酯(6)。在
丙酮中用乙氧羰基异
硫氰酸酯处理6得到5-
硫脲基衍
生物7,经
碘甲烷甲基化后得到1-(2,3 - O-异亚丙基-β-D-
呋喃呋喃糖基)-5-[(N'-乙氧羰基)乙基-小号-methylisothiocarbamoyl)
氨基]
吡唑-4-羧酸酯(8)。闭环8在碱性介质下提供6-
氨基-1-(2,3 - O-异亚丙基-β-D-
呋喃呋喃糖基)-1 H-
吡唑并[3,4- d ] -1,3-恶嗪-4-酮(10) ,在去异亚丙基化后,以良好的收率得到4。还从
AICA核糖苷同源物5-amino-1合成了6-
氨基-1-(β-D-
呋喃呋喃糖基)-1H-
吡唑并[3,4- d ]
嘧啶-4(5