Structure cristalline de la (±)-lupanine

Abstract

Une 6tude plus d6taill6e du mode d'apparition des polytypes hexagonaux de sulfure de titane sera publi6e ult6rieurement. R6f6rences Structure Cristalline de la (4-)-Lupanine PAR HERVl~ DOUCERAIN, ANGI~LE CHIARONI ET CLAUDE RICHE Institut de Chimie des Substances

Crystal and molecular structure of 13-oxolupanine

“…The mean values for Csp3-Csp ~, Csp3-Csp 2, and N-Csp 3 are 1.53114], 1.50014], and 1.47212] A, respectively. The bond lengths within the lactam group of ring A show conjugation between a lone electron pair on N(1) and the ~r-electrons of the carb0nyl group, similar to that in other lupanine structures (Doucerain et al, 1976;Skrzypczak-Jankun and K~uski, 1978;SkrzypczakJankunet al, 1980b;MaCuszyfiska et al, 1979). As a result, a flattening of ring A in the region of N(1)-C(2)-O(2)-C(3) is observed.…”

“…However, they exhibit different crystal packings as there are no intermolecular hydrogen bonds in the structure of 13-oxolupanine, while in that of lupanine 9 HCI" 2H20 the laetam oxygen atom is involved in a three-dimensional hydrogen-bond network. Examination of ring A conformations in other luparfine structures shows that the flexibility of the ring A conformation is quite marked, such that even packing forces weaker than intermolecular hydrogen bonds can cause it to adopt different forms, e.g., half-chair (Mafuszyriska et al, 1979;Skrzypczak-Jankun et al, 1980a), sofa (Doucerain et aL, 1976), distorted chair (Skrzypczak-Jankun et al, 1980b) Ka-l'uski, 1978; this work). The chair conformation of ring D excludes the possibility of a trans-annular effect in the crystal structure of 13-oxolupanine.…”

Lupin alkaloids 6. Stereochemistry of bis-quinolizidine alkaloids with γ-oxo-α,β-enamine system

“…Lupanine has a boat conformation of ring C both in the solid (8) and in solution (9) (more precisely, the conformational equilibrium in solution is heavily shifted towards conformer 5b; cf. ref.…”

“…Such couplings can be explained best by the significant contribution of a "chair" conformer in which the H8proR and H170:, as well as H11 and H 17a, are coplanar. Table 6 lists torsion angles HCCH calculated for multiflorine (1) and 13a-hydroxymultiflorine (2) from the Haasnoot equation (3) and X-ray diffraction data for l (7), lupanine (5) (8), and 13a-hydroxylupanine (6) (10) with the typical geometry of methylene groups taken into account (I I). In the case of some angles, in particular those that belong to rings B and D in 1 and 2, agreement between results obtained via the two methods is satisfactory.…”

Calpurmenin and its 13α-(2'-pyrrolecarboxylic acid) ester

“…The former occurs in a-© 1979 International Union of Crystallography isosparteine (Przybylska & Barnes, 1953), 7-hydroxyfl-isosparteine (Pinkerton & Steinrauf, 1967), fl-isosparteine copper chloride (Childers, Folting, Merritt & Streib, 1975) and sparteine N(16)-oxide (Srivastava & Przybylska, 1969); the latter exists in the lupin alkaloids lupanine N(16)-oxide (compound II: Kaluski, Gusiev, Struchkov, Skolik, Baranowski & Wiewi6rowski, 1972), (+)-lupanine hydrochloride dihydrate (compound III: Skrzypczak-Jankun & Kaluski, 1978) and (+)-lupanine (compound IV: Doucerain, Chiaroni & Riche, 1976). The purpose of the present investigation is the structure determination of the 13-(2'-pyrrolecarboxylic acid) ester of calpurmenin (hereafter I) by X-ray diffraction in order to establish the position and orientation of the substituents and to determine the overall shape of the molecular framework.…”