Collect. Czech. Chem. Commun. 1993, 58, 2944-2954

A Conformational Study of the Semisynthetic Ergot Alkaloid - Terguride

Michal Hušáka, Bohumil Kratochvíla, Petr Sedmerab, Josef Stuchlíkc and Alexandr Jegorova

a Department of Solid State Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6, Czech Republic
b Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20 Prague 4, Czech Republic
c Galena Co., Research Unit, 370 05 České Budějovice, Czech Republic


Conformational analysis studied by 2D NMR techniques and X-ray diffraction methods are reported for the semisynthetic ergot alkaloid - terguride, in the form of free base and as the protonated species. The structure of terguride hydrogen maleate monohydrate (C20H29N4O)+(C4H3O4)- . H2O (II) was solved by direct methods and refined anisotropically to an Rvalue of 0.068 for 1 991 unique observed reflections. The title compound crystallizes in the triclinic space group P1 with lattice parameters a = 7.061(2), b = 9.205(1), c = 12.223(4) Å, α = 96.36(2), β = 107.15(2), γ = 106.67(1)°. Studies revealed that terguride monohydrate (I) and its protonized form (terguride hydrogen maleate monohydrate) possesses the identical conformations both in solutions and in the solid state - an envelope for C and Chair for D ergoline rings.