Identification, isolation and characterization of a pharmaceutical impurity in levocetirizine hydrochloride

2020 ◽  
Vol 16 ◽  
Author(s):  
Shuchen Pei ◽  
Junlin Chen ◽  
Shihao Xia ◽  
Jieyu Wang ◽  
Buyin Xue ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Quaternary Ammonium ◽  
First Generation ◽  
Formation Mechanisms ◽  
Human Metabolite ◽  
Chromatographic Methods ◽  
Isolation And Characterization ◽  
Piperazine Derivative

: Levocetirizine is the active R-enantiomer of the racemate cetirizine, the latter being a piperazine derivative and human metabolite of the first-generation antihistamine hydroxyzine. In this study, a pharmaceutical impurity was detected and isolated through various chromatographic methods. The structure was identified as levocetirizine quaternary ammonium by mass spectrometry and NMR spectroscopy. The formation mechanisms of the impurity were also presented.

A twist on Hellwinkel’s salt, [P(2,2′-biphenyl)2]+[P(2,2′-biphenyl)3]–

2018 ◽  
Vol 96 (6) ◽  
pp. 526-533 ◽  
Author(s):  
Khatera Hazin ◽  
Derek P. Gates
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Spiro Compound ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Isolation And Characterization

Treating PCl5 with C12H8Li2, generated from either C12H10, C12H8Br2, or C12H8I2, affords three products in different ratios depending on the source of the lithiated biphenyl. Hellwinkel’s salt [P(C12H8)2][P(C12H8)3] ([1][2]) and another product [P(C12H8)(C24H16)][P(C12H8)3] ([1′][2]) were obtained by reacting PCl5 with 2,2′-dilithiobiphenyl [Route A: 2.5 equiv.; obtained from biphenyl, n-BuLi, and TMEDA; Route B: 3.0 equiv.; obtained from 2,2′-diiodobiphenyl and n-BuLi; Route C: 4.0 equiv.; obtained from 2,2′-dibromobiphenyl and n-BuLi]. The synthesis, isolation, and characterization of the chiral spiro-compound [1′][2] and the characterization of the pentavalent phosphorane [P(C12H8)2(C12H9)] (3) are reported. The complex [1′][2] was characterized by 31P{1H} NMR spectroscopy, X-ray crystallography, and mass spectrometry. The pentavalent compound (3) was characterized by 31P{1H} NMR spectroscopy and X-ray crystallography.

scholarly journals Characterization of the synthetic cannabinoid MDMB-CHMCZCA

2016 ◽  
Vol 12 ◽  
pp. 2808-2815 ◽  
Author(s):  
Carina Weber ◽  
Stefan Pusch ◽  
Dieter Schollmeyer ◽  
Sascha Münster-Müller ◽  
Michael Pütz ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Hplc Method ◽  
Enantiomeric Purity ◽  
Synthetic Cannabinoid ◽  
Spectroscopic Techniques ◽  
Chiral Hplc ◽  
Tandem Mass ◽  
Synthetic Sample

The synthetic cannabinoid MDMB-CHMCZCA was characterized by various spectroscopic techniques including NMR spectroscopy and tandem mass spectrometry. The synthetic sample was found to be of S-configuration by VCD spectroscopy and comparison of the data with DFT calculations, while ECD spectroscopy was found to be inconclusive in this case. The enantiomeric purity of samples from test purchases and police seizures was assessed by a self-developed chiral HPLC method.

scholarly journals Efficient resolution of racemic crown-shaped cyclotriveratrylene derivatives and isolation and characterization of the intermediate saddle isomer

2019 ◽  
Vol 15 ◽  
pp. 1339-1346
Author(s):  
Sven Götz ◽  
Andreas Schneider ◽  
Arne Lützen
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Nmr Spectroscopy ◽  
High Performance ◽  
Chiral Stationary Phase ◽  
Hplc Separation ◽  
Promising Alternative ◽  
Isolation And Characterization ◽  
C Nmr

The preparative resolution of a trifunctionalized C 3-symmetrical chiral cyclotriveratrylene derivative was achieved via high-performance liquid chromatography (HPLC) on a chiral stationary phase. This approach is a promising alternative to the previously reported resolution through formation of diastereomeric esters because it involves fewer synthetic steps and is less prone to thermal (re)racemization. During these studies an intermediate saddle conformer could also be isolated and characterized by 1H and 13C NMR spectroscopy. The HPLC separation method was further developed in order to allow investigations on the racemization behavior of the cyclotriveratrylene derivative.

Nine- and Eight-Vertex Polyhedral Dicarbaborane Chemistry: New arachno and hypho Dicarbaboranes from arachno-4,5-C2B7H13: Isolation and Characterization of the [arachno-4,5-C2B7H12]- and [hypho-7,8-C2B6H13]- Anions, and of the Neutral Ligand Derivatives exo-6-(MeNC)-arachno-4,5-C2B7H11 and exo-5-L-hypho-4,9-C2B7H13 (L = NMe3 and NEt3)

1994 ◽  
Vol 59 (7) ◽  
pp. 1584-1595 ◽  
Author(s):  
Tomáš Jelínek ◽  
Josef Holub ◽  
Bohumil Štíbr ◽  
Xavier L. R. Fontaine ◽  
John D. Kennedy
Keyword(s):  
Nmr Spectroscopy ◽  
Selective Removal ◽  
High Yield ◽  
Two Dimensional ◽  
Neutral Ligand ◽  
Tertiary Amines ◽  
Proton Sponge ◽  
H Nmr ◽  
Isolation And Characterization

Deprotonation of neutral arachno-4,5-C2B7H13 (1) either with 1, 8-(NMe2)2C10H6 (proton sponge, PS) or with a mixture of aqueous K2CO3 and [NMe4]Cl leads to the isolation in high yield of the [arachno-4,5-C2B7H12]- anion (2). Isostructural with this anion is the ligand derivative exo-6-(MeNC)-arachno-4,5-C2B7H11 (3), which is prepared in 20% yield from the reaction between arachno-4,5-C2B7H13 and MeNC in dichloromethane. Under comparable conditions compound 1 with tertiary amines gives the first representatives of the nine-vertex hypho family of dicarbaboranes, the ligand derivatives exo-5-(NR3)-hypho-4,9-C2B7H13 (4a and 4b, where R = Me and Et, respectively) in moderate yields (20 - 55%), whereas the reaction between 1 and aqueous NaCN results in the selective removal of one boron vertex to yield the eight-vertex [hypho-7,8-C2B6H13]- anion (5) in 61% yield. All compounds isolated were characterized by 11B and 1H NMR spectroscopy, with two-dimensional and selective decoupling techniques giving unambiguous assignments.

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