X-RAY STRUCTURAL STUDY OF TERGURIDE SOLVATES - TERGURIDE METHANOL SOLVATE

The structure of the unstable solvate of the semisynthetic ergot deriv ate - terguride methanol solvate C20H28N4O . CH3OH, was solved by dire ct methods and refined to an R value of 0.093 for 1 462 unique observe d reflections. The title alkaloid crystallizes in the orthorhombic spa ce 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 indo le moiety of the terguride molecule is almost perfect planar, ring C h as an E6 envelope conformation and ring D adopts a C-1(4) chair shape. As found from X-ray powder diffraction study, terguride methanol solv ate completely transforms to terguride monohydrate in air during sever al hours.