@article {MCPHAIL590, author = {ANDREW T. MCPHAIL and MOHAMED B. ABOU-DONIA and GERALD M. ROSEN}, title = {X-ray Crystal Structure and Conformation of a Spin-Labeled Acetylcholine, DL-4-[N,N-Dimethyl-N-(ethan-2{\textquoteright}-olacetate)amino]-2,2,6,6-tetramethylpiperidine-1-oxyliodide}, volume = {12}, number = {4}, pages = {590--597}, year = {1976}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {The detailed molecular geometry of the title compound, a muscarinic blocking agent, has been established by single-crystal X-ray analysis. Crystals are orthorhombic, space group Pbca, a = 18.00(1), b = 11.42(1), c = 18.42(1) A,Z = 8. The structure was solved by the heavy-atom method, and atomic parameters were refined by full-matrix, least-squares calculations to R 0.049 over 1082 statistically significant reflections from diffractometer measurements. Comparison of the results with those for known muscarinic agents revealed that whereas the O-C-C-N+ torsion angle at 78{\textdegree} is similar to those in other potent muscarinic agents, the C-O (ester)-C-C torsion angle at 99{\textdegree} lies outside the range predicted for muscarinic agonists.}, issn = {0026-895X}, URL = {https://molpharm.aspetjournals.org/content/12/4/590}, eprint = {https://molpharm.aspetjournals.org/content/12/4/590.full.pdf}, journal = {Molecular Pharmacology} }