Crystal Structure of 17α-Dihydroequilin, C18H22O2, from Synchrotron Powder Diffraction Data and Density Functional Theory

James Kaduk,Thomas Blanton,Amy Gindhart

doi:10.3390/cryst7070218

Abstract

The crystal structure of 17α-dihydroequilin has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. 17α-dihydroequilin crystallizes in space group P212121 (#19) with a = 6.76849(1) Å, b = 8.96849(1) Å, c = 23.39031(5) Å, V = 1419.915(3) Å3, and Z = 4. Both hydroxyl groups form hydrogen bonds to each other, resulting in zig-zag chains along the b-axis. The powder diffraction pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ as the entry 00-066-1608.

Highlights

Introduction17α-dihydroequilin naturally-occurring steroidal estrogen found the of urine of female17α-dihydroequilin isisa anaturally-occurring steroidal estrogen found in theinurine female horses. ® horses
Its 3-sulfate ester sodium salt is one of the components of Premarin, a mixture of conjugated estrogens estrogens which is used to treat of symptoms of menopause for the of prevention of osteoporosis
Most powder measurements performed at ambient low-temperature single crystal structure often differ significantly from those measured at ambient expansion means that the peak positions calculated from a low-temperature conditions

Summary

Introduction

17α-dihydroequilin naturally-occurring steroidal estrogen found the of urine of female. National Laboratory to include reference patterns in the PDF, and of determine thepharmaceutical crystal structures of theseinclude active measurethese high-quality synchrotron powder patterns commercial ingredients, pharmaceutical ingredients (APIs). Most powder measurements performed at ambient low-temperature single crystal structure often differ significantly from those measured at ambient expansion (generally anisotropic) means that the peak positions calculated from a low-temperature conditions. These peak shifts result in the failure default search/match algorithms to identify a single crystal structure often can differ significantly fromofthose measured at ambient conditions. Critical for straightforward identification of APIs using standard powder diffraction practices

Results

C18 Hof22the

Comparison

Comparison of the and DFT structures of

Materials and Methods

Conclusion