Thalassemia is a genetic blood disorder requiring life‐long blood transfusions. This process often results in iron overload and can be treated by an iron‐chelating agent, like deferiprone (3‐hydroxy‐1,2‐dimethylpyridin‐4‐one), C₇H₉NO₂, in an oral formulation. The first crystal structure of deferiprone, (Ia), was reported in 1988 [Nelson et al. (1988). Can. J. Chem.66, 123–131]. In the present study, two novel polymorphic forms, (Ib) and (Ic), of deferiprone were identified concomitantly with polymorph (Ia) during the crystallization experiments. Polymorph (Ia) was redetermined at low temperature for comparison of the structural features and lattice energy values with polymorphs (Ib) and (Ic). Polymorph (Ia) crystallized in the orthorhombic space group Pbca, whereas both polymorphs (Ib) and (Ic) crystallized in the monoclinic space group P2₁/c. The asymmetric units of (Ia) and (Ib) contain one deferiprone molecule, while polymorph (Ic) has three crystallographically independent molecules (A, B and C). All three polymorphs have similar hydrogen‐bonding features, such as an R₂²(10) dimer formed by O—H…O hydrogen bonds, an R₄³(20) tetramer formed by C—H…O hydrogen bonds and π–π interactions, but the polymorphs differ in their molecular arrangements in the solid state and are classified as packing polymorphs. O—H…O and C—H…O hydrogen bonds lead to the formation of two‐dimensional hydrogen‐bonded parallel sheets which are interlinked by π–π stacking interactions. In the three‐dimensional crystal packing, the deferiprone molecules were aggregated as corrugated sheets in polymorphs (Ia) and (Ic), whereas in polymorph (Ib), they were aggregated as a square‐grid network. The characteristic crystalline peaks of polymorphs (Ia), (Ib) and (Ic) were established through powder X‐ray diffraction analysis. The Rietveld analysis was also performed to estimate the contribution of the polymorphs to the bulk material.

中文翻译：

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铁螯合剂去铁酮的两种新型多晶型形式。

地中海贫血是一种遗传性血液病，需要终生输血。此过程通常会导致铁超负荷，可以通过口服制剂中的铁螯合剂（例如去铁酮（3-羟基1,2-二甲基吡啶-4-酮），C ₇ H ₉ NO ₂）进行处理。1988年，报告了去铁酮的第一个晶体结构（Ia）[Nelson等。（1988）。能够。J.化学 66，123–131]。在本研究中，在结晶实验过程中，与去铁酮（Ia）同时鉴定出两种新的多铁酮形式（Ib）和（Ic）。在低温下重新确定多晶型物（Ia），以比较多晶型物（Ib）和（Ic）的结构特征和晶格能量值。多晶型物（Ia）在正交空间群Pbca中结晶，而多晶型物（Ib）和（Ic）都在单斜晶空间群P 2 ₁ / c中结晶。（Ia）和（Ib）的不对称单元包含一个去铁酮分子，而多晶型物（Ic）具有三个晶体学独立的分子（A，B和C）。这三种多晶型物都具有相似的氢键特征，例如由OH-O氢键形成的R ₂ ²（10）二聚体，R ₄ ³（20）由C–H…O氢键和π–π相互作用形成的四聚体，但多晶型物在固态下的分子排列不同，被分类为堆积多晶型物。O–H…O和C–H…O氢键会导致形成二维氢键键合的平行片，它们通过π–π堆积相互作用相互连接。在三维晶体堆积中，去铁酮分子在多晶型物（Ia）和（Ic）中聚集为波纹片，而在多晶型物（Ib）中则聚集为方格网。通过粉末X射线衍射分析确定了多晶型物（Ia），（Ib）和（Ic）的特征结晶峰。还进行了Rietveld分析，以估算多晶型物对块状材料的贡献。