Crystal and molecular structure of 6α-bromo-17β-hydroxy-17α-methyl-4-oxa-5α-androstan-3-one

Abstract

6a-Bromo-I 7@-hydroxy-I 7a-methyl-Paul," W. A. Noyes Chemical Laboratory, University of The crystal and molecular structure of 6a-bromo-l7~-hydroxy-l7a-methyl-4-oxa-5a-androstan-3-one (I) has been determined by three-dimensional X-ray analysis. The crystals of (I) are orthorhombic with a = 12.23, b = 7.30, and c = 20.1 4 8, and the space group is P212121 with Z = 4. The structure has been refined to an R of 0.1 2 on 1500 reflexions collected photographically. The A : B, B : C, and C : D ring junctions are all trans. The tactone group in ring A is significantly non-planar with a C(2)-C(3)-0(4)-C(5) torsion angle of -23". Some comparisons are made with other molecules containing factone groups. The molecules in the crystal are linked in the c-directon by O-H * 0 hydrogen bonding.barely moved from its original position. Re-positioning the bromine atom so that the angles were more reasonable and calculating structure factors on the new position for bromine and the established positions for atoms of the A and B rings gave an R of 0.43. A Fourier map based on this calculation revealed the position of all the non-hydrogen atoms in the molecule with reasonable molecular dimensions.