Two crystallographic forms and the absolute structure of 5α,14α-androstane,Acta Crystallographica Section C

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Two crystallographic forms and the absolute structure of 5α,14α-androstane
Acta Crystallographica Section C ( IF 0.7 ) Pub Date : 2021-08-20 , DOI: 10.1107/s2053229621008408
Christopher M Crittenden ₁ , Antonio G DiPasquale ₁

Affiliation

5α,14α-Androstane (C₁₉H₃₂) crystallizes in two different polymorphic forms in the same vapor diffusion experiment. The major form (Form I) crystallizes as thin plates in the space group P2₁, with Z = 4. These plates are twinned along a long c axis of length 43 Å and readily suffer from radiation damage when diffracted. The minor form (Form II) crystallizes as fine needles in the space group P2₁2₁2₁, Z = 3. In the minor form, 5α,14α-androstane cocrystallizes with 5α,14α-androstan-17-one, an oxidation product of 5α,14α-androstane. The presence of 5α,14α-androstan-17-one in the minor form of the crystals was confirmed by HR-MS. Form II can be crystallized as a pure form without the ketone impurity using a different solvent system. High level density functional theory (DFT) lattice free energy calculations were performed and show that both pure forms are isoergic within the estimated error of the calculations.

中文翻译：

5α,14α-雄甾烷的两种晶型和绝对结构

5α,14α-雄甾烷 (C ₁₉ H ₃₂ ) 在同一蒸汽扩散实验中以两种不同的多晶型形式结晶。主要形式（形式 I）在空间群P 2 _{1 中}结晶为薄板，Z = 4。这些板沿着长度为 43 Å的长c轴孪晶，并且在衍射时容易受到辐射损伤。次要形式（形式 II）在空间群P 2 ₁ 2 ₁ 2 ₁ , Z 中结晶为细针 = 3. 在次要形式中，5α,14α-雄甾烷与 5α,14α-雄甾烷-17-one（5α,14α-雄甾烷的氧化产物）共结晶。HR-MS 证实了 5α,14α-androstan-17-one 以次要形式的晶体存在。可以使用不同的溶剂系统将形式 II 结晶为不含酮杂质的纯形式。进行了高水平密度泛函理论 (DFT) 晶格自由能计算，结果表明两种纯形式在计算的估计误差内都是等能的。

更新日期：2021-09-06

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