Salim Fatimah, Ahmad Rohaya, Ismail Nor Hadiani, Hazni Hazrina, Ng Seik Weng
Acta Crystallogr Sect E Struct Rep Online. 2011 Jun 1;67(Pt 6):o1345. doi: 10.1107/S1600536811016710. Epub 2011 May 7.
The title penta-cyclic oxindole alkadoid, isolated from Uncaria longiflora, crystallizes as a methanol solvate, C(20)H(22)N(2)O(4)·CH(4)O. The five-membered ring comprising the indole fused ring is nearly planar [maximum atomic deviation = 0.031 (2) Å], whereas the five-membered ring having alphatic C atoms adopts an envelope shape (with the tertiary N atom representing the flap). The six-membered ring that shares an N atom with the envelope-shaped ring adopts a chair shape; the six-membered ring having an O atom is sofa-shaped. The carb-oxy-lic acid group acts as a hydrogen-bond donor to a methanol mol-ecule; this, in turn, acts as a hydrogen-bond donor to the double-bond carboxyl O atom of an adjacent mol-ecule, generating a chain. Adjacent chains are linked by N-H⋯O hydrogen bonds, forming a layer motif.
从长花钩藤中分离得到的标题五环氧化吲哚生物碱，以甲醇溶剂化物C(20)H(22)N(2)O(4)·CH(4)O的形式结晶。包含吲哚稠合环的五元环近乎平面[最大原子偏差 = 0.031 (2) Å]，而具有脂肪族碳原子的五元环呈信封形状（叔氮原子代表封盖）。与信封状环共享一个氮原子的六元环呈椅形；含有一个氧原子的六元环呈沙发形。羧酸基团作为氢键供体与一个甲醇分子相连；反过来，该甲醇分子又作为氢键供体与相邻分子的双键羧基氧原子相连，形成一条链。相邻的链通过N-H⋯O氢键相连，形成层状结构。
