Radical Structure in — Irradiated Single Crystal of 17α- Hydroxyprogesterone
17α - Hydroxyprogesterone is a natural metabolite of the female hormone, progesterone and differs from the latter only by the presence of a hydroxyl group at C17 atom /Fig. 1/. Orthorhombic structure crystals  were grown from acetone solution and γ-irradiated with a dose of 160 kGy. The kind and value of the hyperfine split, obtained from EPR spectra, suggest that the radical is formed by hydrogen atom abstraction from carbon atom C6. The unpaired electron is delocalized on the four carbon atoms C6, C5, C4 and C3 and on the oxygen atom 03. The mean values of the hyperfine interaction tensors are: A=1.13 mT, A1 = 1.96 mT, A2 = 2.58 mT and the tensor of g coefficient /factor/: gx=2.0027, gy=2.20037, gz=2.055.