Thiepine

Thiepine are a group of unsaturated seven-membered sulfur-containing heterocycles, which derive from thiepin. Thiepine itself is an unstable compound and can not be obtained in pure form, however, a number of its derivatives are known. The fully hydrogenated derivative is the Thiepan.

Properties

The Thiepingrundgerüst has the molecular formula C6H6S and has a system of eight π - electrons. Thiepine belong to the group of antiaromatics. The ring is not planar, but is located in a boat conformation before. Thiepine are unstable compounds, which tend to elimination of sulfur under the formation of benzene derivatives. Here, a Thianorcaradien intermediate is formed, from which ultimately the elimination of sulfur is a benzene derivative is formed. The driving force for this reaction is the formation of an aromatic system.

Stabilization

Thiepine can be stabilized by the substituents, which impede the formation of the planar Thianorcaradien ring. These include, for example, sterically demanding alkyl groups such as tert- butyl radicals. As has 2,7- di-tert- butylthiepin in refluxing toluene a half-life of 365 hours. And substituents at the C3 and C6 carbon atoms have a stabilizing effect. If there are, however, two substituents at the C4 and C5, they usually act destabilizing. The reason for this is that these substituents hinder each other more in the seven- membered ring than in the six-membered ring. The decomposition of benzene derivative thus causes relaxation.

Use

There are medicines whose active substances are Thiepinderivate. These include the atypical antipsychotic zotepine and the antidepressant dosulepin.