An impurity from the synthesis of Levonorgestrel (N689510), an oral contraceptive.

Yoshida, F. et al.: J. Am. Chem., 43, 2575 (2000); Chem. Res. Tox., 21, 2280 (2008); Holm, R. et al.: Phys. Chem. Chem. Phys., 11, 5070 (2009);