Butopyronoxyl（Cat No.:R069331）is a stable nitroxide free radical compound used primarily as a spin label and spin probe in electron paramagnetic resonance (EPR) spectroscopy. It serves as a molecular tool to investigate membrane dynamics, molecular motion, and microenvironments in biological systems. Due to its paramagnetic nature, butopyronoxyl can detect changes in oxygen concentration and lipid membrane fluidity. Its structural stability and reactivity make it suitable for studying redox biology and oxidative stress. Though not used therapeutically, it holds significant value in biochemical and biophysical research, particularly in the fields of membrane biochemistry and free radical biology.