Rp. Litvinovskaya et al., Crystal and molecular structure of (5 ' R)-17 beta-hydroxy-17 alpha-(3 '-isopropylisoxazolin-5 '-yl)-3-methoxyestra-1,3,5 (10)-triene, RUSS J G CH, 70(9), 2000, pp. 1476-1479
The crystalline minor epimer formed by 1,3-dipolar cycloaddition of isobuty
ronitrile oxide to 17 beta -hydroxy-17-vinylsteroids relates to the space g
roup C2; the stereochemistry of the newly formed chiral center is 5'R. The
molecules in the structure are dimerized due to H-bond formation.