Halogen bonding of neutral donors using imine groups of porous organic cage compounds as acceptors leads to the formation of halogen-bonded frameworks. We report the use of two different imine...

Crystallization and multicomponent crystal formation of active pharmaceutical ingredients Baclofen and Phenibut with dicarboxylic acid co-formers are discussed. The crystallization process of several crystalline entities is elucidated via single crystal—as well as powder X-ray—diffraction, followed by thermal analysis and phase stability studies over time. Both APIs form increasingly complex crystalline phases with co-formers malic and tartaric acid, where phase purity of a desired compound is not necessarily a given. Therefore, the influence of different solution and milling environments during crystallization on the outcome is studied. Emphasis is laid on how molecular influences such as the chirality, propensity to form hydrates as well as low solubility of Baclofen and Phenibut impede attempts to gather high-quality single crystals. The results highlight that targeted crystallization of these compounds with dicarboxylic acids can be difficult and unreliable.

We present several multicomponent crystalline species formed by zwitterionic GABA analogues Pregabalin and Phenibut. These compounds are evaluated based on their crystal structure in congruence with properties such as melting...

The controlled pH-based crystallization approach with acetic acid to the pharmaceutical interesting metastable polymorph II of the API γ-aminobutyric acid (GABA), which is hitherto accessible by sublimation under reduced pressure and high temperature, is described. Furthermore, the synthesis and single crystal characterization of a nonhydrated chiral [GABA-H][malate] compound is presented.

A typical approach of a multicomponent crystal design starts with a retrosynthetic analysis of the target molecule followed by a one-pot reaction of all components. To develop protocols for multicomponent crystal syntheses, controlled stepwise syntheses of a selected crystalline ternary multicomponent system 1 involving 2-methylresorcinol (MRS), tetramethyl-pyrazine (TMP), and 1,2-bis(4-pyridyl)ethane (BPE) are presented. The obtained binary cocrystals 2 (involving MRS and TMP) and 3 (involving MRS and BPE) as well as the final resulting ternary multicomponent system 1 were characterized by X-ray analysis.