Tethered derivatives of d-glucose and pentacyclic triterpenes for homo/heterobivalent inhibition of glycogen phosphorylase
作者:Keguang Cheng、Jun Liu、Hongbin Sun、Éva Bokor、Katalin Czifrák、Bálint Kónya、Marietta Tóth、Tibor Docsa、Pál Gergely、László Somsák
DOI:10.1039/b9nj00602h
日期:——
Propargyl esters of the C-28 carboxylic acids of pentacyclic triterpenes (oleanolic, ursolic, and maslinic acids) were coupled with 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl azide as well as N-(ω-azido-[C-2, C-6, and C-11]alkanoyl)-β-D-glucopyranosylamines under conditions of copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) to give tethered D-glucose–triterpene heteroconjugates. The O-acetyl protecting groups were removed by base-catalyzed hydrolysis. N-(ω-Azido-[C-2, C-6, C-11, and C-16]alkanoyl)-β-D-glucopyranosylamines were also tethered by 1,7-octadiyne under CuAAC conditions to furnish D-glucose homoconjugates. O-Deacetylation was carried out by the Zemplén protocol. The new compounds were assayed against rabbit muscle glycogen phosphorylase (RMGP) a or b enzymes. Some of the heteroconjugates inhibited the enzyme in the low micromolar range (IC50 values 40–70 μM), while the homoconjugates proved inefficient as inhibitors.
五环三萜的 C-28 羧酸(齐墩果酸、熊果酸和山楂酸)的炔丙酯与 2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖基叠氮化物以及 N-( ω-叠氮基-[C-2、C-6和C-11]烷酰基)-β-D-吡喃葡萄糖胺在铜(I)催化的叠氮化物-炔环加成(CuAAC)条件下生成束缚的D-葡萄糖-三萜异共轭物。通过碱催化水解除去O-乙酰基保护基团。 N-(ω-叠氮基-[C-2、C-6、C-11 和 C-16]烷酰基)-β-D-吡喃葡萄糖胺也在 CuAAC 条件下被 1,7-辛二炔束缚以提供 D-葡萄糖同缀合物。 O-脱乙酰化通过 Zemplén 方案进行。新化合物针对兔肌糖原磷酸化酶 (RMGP) a 或 b 酶进行了检测。一些杂合物在低微摩尔范围内抑制酶(IC50 值 40-70 μM),而同聚物作为抑制剂被证明是无效的。