Research Article: 1-(1-Hy­droxy­eth­yl)-7,8-dihydro­indolo[2,3-a]pyridine­[3,4-g]quinolizin-5(13H)-one (angustoline) monohydrate from Nauclea subdita (Rubiaceae)

Date Published: July 01, 2011

Publisher: International Union of Crystallography

Author(s): Sook Yee Liew, Mat Ropi Mukhtar, Khalijah Awang, Mohd Rais Mustafa, Seik Weng Ng.


The title compound (trivial name: angustoline monohydrate), C20H17N3O2·H2O, features a fused-ring system formed by one five- and four six-membered rings. The nearly planar benzimidazole portion (r.m.s. deviation = 0.008 Å) and the nearly planar 2,7-naphthyridin-1-one portion (r.m.s. deviation = 0.022 Å) of the fused-ring system are slightly twisted, with a dihedral angle of 9.47 (8)°, owing to the tetra­hedral nature of the two methyl­ene linkages in the central six-membered ring. The secondary N atom acts as a hydrogen-bond donor to the water molecule of crystallization. In the crystal, the amino and hy­droxy groups, and the water mol­ecule are engaged in hydrogen bonding, generating a three-dimensional network.

Partial Text

For the isolation of the title compound from other plants, see: Abreu & Pereira (1998 ▶, 2001 ▶); Au et al. (1973 ▶); Carte et al. (1990 ▶); Erdelmeier et al. (1992 ▶); Fan et al. (2010 ▶); Hotellier et al. (1975 ▶); Kakuguchi et al. (2009 ▶); Lin et al. (1988 ▶); Sun et al. (2008 ▶); Xuan et al. (2007 ▶); Zeches et al. (1985 ▶).




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