X-Ray Structural Study Of Terguride Solvates - Terguride Methanol Solvate

The structure of the unstable solvate of the semisynthetic ergot derivate - terguride methanol solvate C20H28N4O . CH3OH, was solved by direct methods and refined to an R value of 0.093 for 1 462 unique observed reflections. The title alkaloid crystallizes in the orthorhombic space group P2(1)2(1)2, with lattice parameters a = 10.438(1), b = 13.200(4), c = 15.495(5) angstrom , V = 2 134.8(9) angstrom3, Z = 4. An indole moiety of the terguride molecule is almost perfect planar, ring C has an E6 envelope conformation and ring D adopts a C-1(4) chair shape. As found from X-ray powder diffraction study, terguride methanol solvate completely transforms to terguride monohydrate in air during several hours.