Crystal and molecular structure of 17-β-methyllupanine N(16)-oxide perchlorate hemihydrate

Authors:

• Andrzej Katrusiak,
• Z. Kaluski

Abstract

[C₁₆H₂₇N₂O₂]⁺·C1O₄^-·1/2H₂O, M_r=387.86, is monoclinic:P2₁, a=8.934(1), b=14.625(1), c=14.449(1) Å, β=103.03(1)°, V_c=1839.3(2) ų, Z=4, D_x=1.40(1) g cm^-3, λ(Cu Kα)=1.54178 Å, μ(Cu Kα)=20.29 cm^-1, F(000)=808 e, T=292K, R=0.057 for 3428 observed reflections. Two independent cations are connected into chains along [101] by short hydrogen bonds between their oxygen atoms O(C2) and O(N16); distances, 2.607(5) and 2.625(5) Å. The water molecule has short contacts with the two independent perchlorate anions, which indicates that the anions are linked by weak hydrogen bonds utilizing the water molecule. The conformations of the two independent cations are similar and can be described as distorted half-chair, chair, distorted boat, and chair for rings A, B, C, and D, respectively. Except for the flexible ring A, few changes in conformation of the cations are observed in comparison to the cations of lupanine N(16)-oxide perchlorate or 17-β-meth-yllupanine perchlorate. © 1988 Plenum Publishing Corporation.