82-95-1Relevant articles and documents
Buclizine crystal forms: First Structural Determinations, counter-ion stoichiometry, hydration, and physicochemical properties of pharmaceutical relevance
Bitencourt, Monalisa,Doriguetto, Antonio Carlos,Freitas, Jennifer Tavares Jacon,Viana, Andre Luiz Machado,Viana, Olimpia Maria Martins Santos,de Melo, Cristiane Cabral
, (2020)
Buclizine (BCZ) is a chiral synthetic piperazine derivative which has antihistaminic, anti-muscarinic and antiemetic properties, and has been reintroduced as an appetite stimulant, especially for pediatric patients. Structural information about this drug, as well as other buclizine crystalline forms (solvates, salts and co-crystals) including the BCZ free-base (BCZ-FB), is non-existent. Here, we present for the first time the crystal structure of the monohydrochloride monohydrate salt of BCZ (BCZHCl·H2O), and of its anhydrous form, BCZHCl. Interestingly, BCZHCl·H2O was obtained by recrystallization from the raw material (BCZH2Cl2) in ethanol:water solution showing that BCZ anhydrous dihydrochloride salt changes easily to a monohydrochloride monohydrate salt modification, which raise concerns about formulation quality control. BCZHCl·H2O and BCZHCl crystallize in the orthorhombic space groups (Pna21 and Pca21) belonging to the mm2 point group and are thus classified as non-centrosymmetric achiral structures (NA). Intuitively, we expect these salts to crystallize in a space group with a center of symmetry, since less than 5% of the known racemic compounds crystallize in the NA type. The crystal structures of BCZH2Cl2 and BCZ-FB were not determined, but their existence was verified by other techniques (chloride ion analysis, PXRD, HPLC, FT-IR, DSC, TGA) and by comparison of the obtained results with those found for BCZHCl. Additionally, we have also performed an evaluation of the equilibrium solubility (at six different aqueous media) and the dissolution profile of the BCZHCl salt compared to the raw material and BCZ-FB. Different equilibrium solubility values were found comparing the three forms in acidic and neutral pH ranges and all of them were insoluble at pH > 7.0. Moreover, tablets prepared with BCZH2Cl2, BCZHCl or BCZ-FB show significant differences in terms of dissolution profile.
Photocatalytic Water-Splitting Coupled with Alkanol Oxidation for Selective N-alkylation Reactions over Carbon Nitride
Xu, Yangsen,Zhang, Zhaofei,Qiu, Chuntian,Chen, Shaoqin,Ling, Xiang,Su, Chenliang
, p. 582 - 589 (2020/12/09)
Photocatalytic water splitting technology (PWST) enables the direct use of water as appealing “liquid hydrogen source” for transfer hydrogenation reactions. Currently, the development of PWST-based transfer hydrogenations is still in an embryonic stage. Previous reports generally centered on the rational utilization of the in situ generated H-source (electrons) for hydrogenations, in which photogenerated holes were quenched by sacrificial reagents. Herein, the fully-utilization of the liquid H-source and holes during water splitting is presented for photo-reductive N-alkylation of nitro-aromatic compounds. In this integrate system, H-species in situ generated from water splitting were designed for nitroarenes reduction to produce amines, while alkanols were oxidized by holes for cascade alkylating of anilines as well as the generated secondary amines. More than 50 examples achieved with a broad range scope validate the universal applicability of this mild and sustainable coupling approach. The synthetic utility of this protocol was further demonstrated by the synthesis of existing pharmaceuticals via selective N-alkylation of amines. This strategy based on the sustainable water splitting technology highlights a significant and promising route for selective synthesis of valuable N-alkylated fine chemicals and pharmaceuticals from nitroarenes and amines with water and alkanols.
