Stereochemistry of benzodiazepine receptor ligands. Possible role of C-H ⋯X interactions in drug-receptor binding and crystal structures of CL218-872, zopiclone and DMCM

The crystal structures of three benzodiazepine (BDZ)- receptor ligands, i.e. CL218-872, Zopiclone and DMCM, are reported. CL218-872 crystallizes in the space group Pccn with a = 22.624(2), b = 13.073(2), c = 8.385(1) Å. 1 160 reflections with l > 3σ(l) were used in the refinement. The structure was solved by direct methods and refined by weighted full-matrix least-squares with anisotropic non-H and isotropic H atoms to R = 0.038. Zopiclone crystallizes in the space group p212121 with a = 5.567(3), b = 8.852(2), c = 35.677(17) Å. 915 reflections with / > 1.5σ(/) were used in the refinement. The structure was solved by direct methods and refined by weighted fullmatrix least-squares with anisotropic non-H and calculated H atoms to R = 0.060. DMCM crystallizes in the space group P2,/n with a = 13.801 (3), 0 = 10.980(2), c = 10.620(2) Å, β= 103.81(2)°. 1 857 reflections with / > 2σ(/) were used in the refinement. The structure was solved by direct methods and refined by weighted full-matrix...