The crystal structures, molecular structures, and absolute configurations of the hydrobromides of the aporphine alkaloids leucoxine and isoboldine

Abstract

The X-ray crystal-structure analysis of leucoxine (I) hydrobromide (C20H21OsN.HBr) completes the elucidation of the molecular structure of this alkaloid and establishes its absolute configuration as that of the S series of aporphines. The structure analysis of isoboldine (II) hydrobromide (Cj9H2104N .HBr) furnishes details of its molecular structure and confirms the absolute configuration (also S series) implied from the configurational assignment made previously for its isomer isoboldine from an optical rotatory dispersion study. The twist from coplanarity about the central bond of the biphenyl moiety is ~14 ° in (I).HBr and ~21 o in (II).HBr (cf. ~30 ° in the N-methylbulbocapninium ion). The different twists result from the different substituents on the basic aporphine ring system. Both hydrobromides are orthorhombic (P2~2~21) with Z = 4.

Antipoliovirus Structure−Activity Relationships of Some Aporphine Alkaloids

“…According to AM1 calculations, in the H-6a-α-series of aporphines, the energetically favored conformations are those in which the NCH 3 exhibit a pseudo-trans/pseudoaxial position in their free base form and a pseudo-trans/pseudoequatorial position in their protonated form. This latter result fits the X-ray crystal structure of isoboldine hydrobromide . In the absence of information about the interaction between substrate and target, the conformational studies were performed both on the free base and on protonated forms in their lowest energy conformation.…”

“…This latter result fits the X-ray crystal structure of isoboldine hydrobromide. 20 In the absence of information about the interaction between substrate and target, the conformational studies were performed both on the free base and on protonated forms in their lowest energy conformation. The conformational analysis was directed at predicting the preferred states about τ 1 (C 2 -C 1 -O 1 -X 1 ) and τ 2 (C 3 -C 2 -O 2 -X 2 ) dihedral angles for isoboldine (7) and N-methyllaurotetanine (4), both strong antipoliovirus compounds, and for the inactive boldine (6) (X ) H or CH 3 ).…”

Configurational Study of an Aporphine Alkaloid from Annona purpurea

“…The absolute configuration (AC) of aporphine alkaloids has been established by optical rotatory dispersion [13], electronic circular dichroism [14,15] and X-ray diffraction [16,17]. These methods allowed to correlate the AC to their substitution pattern, specific rotation, or the sign of their Cotton effect [10], since it has been established that aporphines possessing two or more oxygenated substituents in ring D possess the S configuration, while aporphines with or without one substituents on that ring may have R or S configuration [18].…”

The molecular structure of adrenergic and dopaminergic substances

“…42 Leucoxine Brown & Hall (1977) H3CO Brown & Hall (1977) 44 iV,AT-Dipropyl-5hydroxy-( + )-2aminotetralin Giesecke (1979a) VI. INTERATOMIC BOND LENGTHS AND ANGLES (A) The average model Interatomic bond lengths and angles for all 44 compounds were used to calculate an average model ( Fig.…”