X-ray crystal structure
Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract An improved synthesis of 20-thiocrown-4 is reported, which exploits the Kellogg method of cesium carbonate in DMF mediated macrocyclization of precondensed synthones which converge at the cycloicosane structure. The crystal structure of 20-thiocrown-4 reveals a rectangular conformation for the free ligand. Each sulfur is in onegauche and oneanti torsion angle. Four carbon positions make up the corners. There are two short sides comprised of −C−C− torsion angle sequencesg −ag− and two long sides (aaa, g −ag+). The S−C and C−C bond distances average 1.816(2) Å and 1.523(3) Å, respectively.
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