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. 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. 3-Oxetanone is a liquid at room temperature, that boils at 140 °C. It is a specialty chemical, used for research in the synthesis of other oxetanes of pharmacological interest.Oxetan-3-one also has been the object of theoretical studies.