3,3-Dimethyl-5-tridecyl-2,3,7,8-tetrahydro-1,4-oxazonin-9(6H)-one is an impurity in the synthesis of 5-DOXYL-stearic Acid, Free Radical (D535528), a spin label that is used for investigating structural changes in lipids. 5-DOXYL-stearic Acid, Free Radical can also be used in biological study of C-edge loops of arrestin function as membrane anchor.