▎ 摘　　要

The H-1 and C-13 NMR spectra of 17-alpha-ethinylestradiol (EE2), a well-known contraceptive, including diastereotopic methylene groups, were fully assigned with the help of residual dipolar couplings (RDC) measured in the recently developed grafted graphene oxide orienting medium. RDC analysis, which included all D-1(CH) couplings and the long-range D-2(CH) H-1-C C-13 coupling, also pointed to the presence of a minor conformation arising from pseudo-rotation of the steroid B ring. Saturation-transfer difference (STD) measurements revealed that the most likely interaction between EE2 and orienting medium occurred on the C and D ring. Copyright (C) 2016 John Wiley & Sons, Ltd.