The Novel GABAA Receptor Ligand NNC 14-0764: 5-(3-Cyclopropyl-1,2,4-oxadiazol-5-yl)-2,3-dihydrodiimidazo[1,5-a:1',2'-c]quinazoline

Abstract

The structure was solved by direct methods and refined by full-matrix least squares using SHELX76 (Sheldrick, 1976). A difference map after anisotropic refinement of the TTT molecule revealed the peaks for all H atoms of TTT and additional prominent peaks near the inversion centre at t, I l a These peaks were identified, with difficulty, as the disordered acetone solvate, based on the interpretation of the geometrical relationships of the peaks, the NMR spectra and the elemental analysis data of the crystal. In the final cycle of refinement, each H atom was assigned a fixed isotropic displacement parameter 1.3 times greater than the isotropic equivalent of the atom to which it is attached. H atoms in the acetone molecule could not be located and were not included in the structurefactor calculations.