Crystallization of a Desired Metastable Polymorph by Pseudoseeding, Crystal Structure Solution from Its Powder X-ray Diffraction Data, and Confirmation of Polymorphic Transition
Crystallization of a Desired Metastable Polymorph by Pseudoseeding, Crystal Structure Solution from Its Powder X-ray Diffraction Data, and Confirmation of Polymorphic Transition
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DOI：
10.1021/cg034051u
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发表时间：
2003-07
影响因子：
3.8
通讯作者：
H. Miura;T. Ushio;K. Nagai;D. Fujimoto;Z. Lepp;Hiroki Takahashi;R. Tamura
中科院分区：
文献类型：
--
作者：
H. Miura;T. Ushio;K. Nagai;D. Fujimoto;Z. Lepp;Hiroki Takahashi;R. Tamura
描述了（±）-[2-[4-（2-甲氧基苯基）氨基]-3-甲基-2-苯基]-2-甲基-3-甲基-2-甲基-（3-乙氧基-2-羟基丙氧基）苯基氨基甲酰基]乙基]二甲基锍对甲苯磺酸盐（1a），其被认为作为与优先富集机理相关的瞬时关键中间体结晶相存在，在从溶剂中结晶某种外消旋体时观察到的不寻常的对映体拆分现象。在过饱和溶液中假晶种（pseudo-seeding）δ晶种，可得到（±）-1a的δ晶型，为单相粉末样品。这种选择性结晶可以解释为不希望的稳定α-多晶型的成核或晶体生长过程的抑制与通过外延生长的所希望的亚稳δ-形式的异质成核之间的相互作用。对δ型晶体的熔点、溶解度等理化性质进行了测定。
Described are the successful, selective crystallization and characterization of one (δ-form) of the metastable polymorphs of (±)-[2-[4-(3-ethoxy-2-hydroxypropoxy)phenylcarbamoyl]ethyl]dimethylsulfonium p-toluenesulfonate (1a), which is assumed to exist as a transient key-intermediate crystalline phase relevant to the mechanism of Preferential Enrichment, an unusual enantiomeric resolution phenomenon observed upon crystallization of a certain kind of racemates from solvents. By pseudoseeding the supersaturated solution with the δ-form seed crystals of an anlogous compound, the desired δ-form crystals of (±)-1a could be obtained as a monophasic powder sample. This selective crystallization can be interpreted in terms of the interplay between an inhibition of the nucleation or crystal growth process of the undesired stable α-polymorphic form and a heterogeneous nucleation of the desired metastable δ-form through epitaxy. The physicochemical properties of the δ-form crystal such as melting point and solubilit...