Pleconaril Polymorphs: Crystal Structures of Form I and Form III, Evidence of the Enantiotropy, and Assessment of the Structural Purity
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- 作者：Servane Coste ; Jean-Marie Schneider ; Marie-Noë ; lle Petit ; and Gé ; rard Coquerel
- 刊名：Crystal Growth & Design
- 出版年：2004
- 出版时间：November 2004
- 年：2004
- 卷：4
- 期：6
- 页码：1237 - 1244
- 全文大小：611K
- 年卷期：v.4,no.6(November 2004)
- ISSN：1528-7505
文摘
Form I (HT) and form III (LT) of pleconaril are enantiotropically related with a calculated temperatureof transition T
= 35.7 
C (supposing an ideal behavior). Structural data obtained from single crystal X-ray diffractionat 100 K and room temperature show that (i) form I (HT) can be described as a network of dimers and form III canbe described as a three-dimensional weakly H-bonded network of monomers. (ii) These two varieties contradict thedensity rule. (iii) The solid-solid transition (not observed) could only occur via a destructive-reconstructivemechanism. Investigations on the pleconaril-ethanol binary system show that the conversion form I 
form III atT = 31 ± 2 C is only possible when mediated by a solvent. A favorable set of thermodynamical and kinetic conditionsallows quantification of form I in form III down to 0.1% by using differential scanning calorimetry. To assess thestructural purity, this method could be applied to other compounds fulfilling five restrictive conditions.
= 35.7 C (supposing an ideal behavior). Structural data obtained from single crystal X-ray diffractionat 100 K and room temperature show that (i) form I (HT) can be described as a network of dimers and form III canbe described as a three-dimensional weakly H-bonded network of monomers. (ii) These two varieties contradict thedensity rule. (iii) The solid-solid transition (not observed) could only occur via a destructive-reconstructivemechanism. Investigations on the pleconaril-ethanol binary system show that the conversion form I form III atT = 31 ± 2 C is only possible when mediated by a solvent. A favorable set of thermodynamical and kinetic conditionsallows quantification of form I in form III down to 0.1% by using differential scanning calorimetry. To assess thestructural purity, this method could be applied to other compounds fulfilling five restrictive conditions.