ISSN 1070-3632, Russian Journal of General Chemistry, 2010, Vol. 80, No. 7, pp. 1324–1330. © Pleiades Publishing, Ltd., 2010. Original Russian Text © S.N. Morozkina, Sh.N. Abusalimov, G.L. Starova, S.I. Selivanov, A.G. Shavva, 2010, published in Zhurnal Obshchei Khimii, 2010, Vol. 80, No. 7, pp. 1158–1164. 1324 Synthesis and Structure of Some 8α-Analogs of Steroid Estrogens S. N. Morozkina, Sh. N. Abusalimov, G. L. Starova, S. I. Selivanov, and A. G. Shavva St. Petersburg State University, Universitetskii pr. 26, St. Petersburg, 198504 Russia e-mail: Alexandr.Shavva@gmail.ru Received December 24, 2009 Abstract—The distances between the protons of four 8α-analogues of steroid estrogens as determined by X-ray data are consistent with the calculated values obtained by ab initio, PM3 and MM+ methods, that can be used for docking of these stereochemical analogs onto α-estrogen receptors. The broad clinical application of modified steroid estrogens [1–4] revealed the presence of a variety of significant side effects, so the search for new substances of this group of hormones with improved biological properties remains an actual task. Since the synthesis of new steroids is very laborious it is essencial to pre-evaluate potential biological properties of the model substances. To forecast the efficiency of ligand binding with different proteins (in particular, with nuclear estrogen receptors) computer simulation is used [5–13] by docking ligands to the appropriate site of a protein. Therefore the choice of method for calculating the conformations of model steroids of a certain stereochemical series is crucial. In the first stage of solving the problem the results of X-ray diffraction (XRD) of model compounds and computer simulation carried out using ab initio and semiempirical methods [14] are compared. The aim of the current work was to study the structures of 8α-analogs of steroid estrogens, as this group of steroids may have better biological properties than the compounds with the natural ring junction [15–22]. In selecting model compounds for the study we took into account that the 8α estrogen analogs with hydroxy groups at C 3 and C 17 effectively bind with the α-estrogen receptors [16, 17]. Since in the crystals of such compounds conformers may appear, whose formation is caused by intermolecular hydrogen bonds, we chose as the model compounds 8α-analogs I–IV lacking hydroxy groups at C 3 and C 17 . The choice of modifications in the carbon skeleton is connected with a noticeable influence of the substituents on the uterotropic action of the analogs [18–20]. DOI: 10.1134/S1070363210070182 O CH 3 H H H OAc H 3 C I AcO H H H II O CH 3 O H H H OAc H 3 C III O H H H OAc H 3 C IV CH 3 O