合成了一系列新颖的腺苷3',5'-环一磷酸(cAMP)类似物,以及它们的6-脱氨基和6-硝基衍生物,其中嘌呤环被吲唑,苯并三唑和苯并咪唑代替。还制备了吲唑和苯并三唑呋喃核糖苷的3',5'-环单磷酸酯,其中糖-磷酸酯部分连接到杂环的N-2氮原子上。通过类似物激活兔骨骼肌中纯化的cAMP依赖性蛋白激酶I(PK-I)和牛心脏中cAMP依赖性蛋白激酶II(PK-II)的能力来测试其生物活性。每个环状核苷酸均能够以2.0 x 10(-8)至4.8 x 10(-6)M的一半最大浓度(Ka)激活两种PK同工酶。N-1-β-D-呋喃呋喃糖基吲唑的环状磷酸酯(13)被证明是对PK-1和PK-II的极弱活化剂,但是当吲唑被N-2结合到核糖上或当C处的氢原子时-4被硝基或氨基取代,类似物的活性大大增加。苯并三唑衍生物的活化能力与cAMP相似,而与C-4取代基无关。发现含有苯并咪唑的环状核苷酸的Ka'值对于PK-
Regioselective Synthesis of Indazole N1‐ and N2‐(β‐d‐Ribonucleosides)
摘要:
The regioselective synthesis of 4-nitroindazole N-1- and N-2- (beta-D-ribonucleosides) (8, 9, 1b and 2b) is described. The N-1-regioisomers are formed under thermodynamic control of the glycosylation reaction [fusion reaction or Silyl Hilbert-Johnson glycosylation for 48 h (66%)], while the kinetic control (Silyl Hilbert-Johnson glycosylation for 5 h) afforded only the N-2-isomer (64%). The structures of the nucleosides 1b and 2b were assigned by single crystal X-ray analyses. The 4-amino-N-1-(beta-D-ribofuranosyl)-1H-indazole (3b) was obtained from the nitro nucleoside 1b by catalytic hydrogenation. Compound 3b shows fluorescence while the 4-nitroindazole nucleosides 1b and 2b do not possess this property.