Conformation of glyburide in the solid state and in solution.

Nuclear magnetic resonance spectroscopy was combined with X-ray crystallography to determine the solution and solid-state conformations of glyburide (C23H28CIN3O5S). In solution, there is apparently free rotation about several of the single bonds. Crystals of glyburide belong to space group P2(1)/n with a = 9.414(3)A, b = 17.591(5)A, c = 14.410(4)A, beta = 93.42(3) degrees, V = 2382(1)A3, R = 0.0694, Z = 4. In the solid, the conformation about all of the bonds is frozen. The torsion angles about some of the important bonds are: C(7)-N(8)-C(9)-C(10), -86 degrees; N(8)-C(9)-C(10)-C(11), -179 degrees (extended); S(17)-N(18)-C(19)-N(20), 178 degrees (extended); and N(18)-C(19)-N(20)-C(21), -179 degrees (extended). Thus, except for the N(8)-C(9) bond, the conformation in the solid state is extended. The solution and solid-state NMR spectra are different as might be expected based on the differences in conformation discussed above.