Four-membered rings

Thietane is a heterocyclic compound containing a saturated four-membered ring with three carbon atoms and one sulfur atom. Some derivatives are of interest as drugs.

Azete, also known as azacyclobutadiene, is a heterocyclic compound consisting of an unsaturated four-membered ring with three carbon atoms and one nitrogen atom. It is inherently unstable due to its 4π-electron antiaromatic character and the strain of the four-membered ring.

chemical compound

Thiete is a heterocyclic compound containing an unsaturated four-membered ring with three carbon atoms and one sulfur atom. It is more commonly encountered not on its own, but in anellated derivatives, several of which have been synthesized. Thietes are generally not very stable.

chemical compound

chemical compound

3-Oxetanone, also called oxetan-3-one or 1,3-epoxy-2-propanone, is a chemical compound with formula C3H4O2. It is the ketone of oxetane, and an isomer of β-propiolactone.

Cyclobutyne (C4H4) is a hydrocarbon molecule containing a triple bond within a four carbon atom ring. This cycloalkyne is very unstable due to its high ring strain and has not been isolated in the pure state. However, osmium coordination complexes containing cyclobutyne have been synthesized.

chemical compound

Oxetene is an unsaturated heterocycle. The compound is unstable and has been synthesized. Compared to oxetane, the saturated compound, oxetene is destabilized because the double bond increases the ring strain. Synthesis of some substituted derivatives has been reported.

chemical compound

Benzocyclobutadiene is the simplest polycyclic hydrocarbon, being composed of an aromatic benzene ring fused to an anti-aromatic cyclobutadiene ring. It has chemical formula . Though the benzene ring is stabilized by aromaticity, the cyclobutadiene portion has a destabilizing effect. This results into it being a non-aromatic compound - neither behaving as aromatic nor an antiaromatic one. For this reason, benzocyclobutadiene will readily dimerize or polymerize and it reacts as a dienophile in Diels-Alder reactions.

Dithiete is an unsaturated heterocyclic compound that contains two adjacent sulfur atoms and two sp2-hybridized carbon centers. Derivatives are known collectively as dithietes or 1,2-dithietes. With 6 π electrons, 1,2-dithietes are examples of aromatic organosulfur compounds. A few 1,2-dithietes have been isolated; one (low-yielding) route is oxidation of a dithiolene complex. 3,4-Bis(trifluoromethyl)-1,2-dithiete is a particularly stable example.