Crystal structure analysis of the biologically active drug molecule riluzole and riluzolium chloride

This study is an investigation into the crystal structure of the biologically active drug molecule riluzole [RZ, 6-(trifluoromethoxy)-1,3-benzothiazol-2-amine], C8H5F3N2OS, and its derivative, the riluzolium chloride salt [RZHCl, 2-amino-6-(trifluoromethoxy)-1,3-benzothiazol-3-ium chloride], C8H6F3N...

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Main Authors: Pradip Kumar Mondal, Athulbabu T, Varun Rao, Deepak Chopra
Format: Article
Language:English
Published: International Union of Crystallography 2019-08-01
Series:Acta Crystallographica Section E: Crystallographic Communications
Subjects:
Online Access:http://scripts.iucr.org/cgi-bin/paper?S2056989019009022
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author Pradip Kumar Mondal
Athulbabu T
Varun Rao
Deepak Chopra
author_facet Pradip Kumar Mondal
Athulbabu T
Varun Rao
Deepak Chopra
author_sort Pradip Kumar Mondal
collection DOAJ
description This study is an investigation into the crystal structure of the biologically active drug molecule riluzole [RZ, 6-(trifluoromethoxy)-1,3-benzothiazol-2-amine], C8H5F3N2OS, and its derivative, the riluzolium chloride salt [RZHCl, 2-amino-6-(trifluoromethoxy)-1,3-benzothiazol-3-ium chloride], C8H6F3N2OS+·Cl−. In spite of repeated efforts to crystallize the drug, its crystal structure has not been reported to date, hence the current study provides a method for obtaining crystals of both riluzole and its corresponding salt, riluzolium hydrochloride. The salt was obtained by grinding HCl with the drug and crystallizing the obtained solid from dichloromethane. The crystals of riluzole were obtained in the presence of l-glutamic acid and d-glutamic acid in separate experiments. In the crystal structure of RZHCl, the –OCF3 moiety is perpendicular to the molecular plane containing the riluzolium ion, as can be seen by the torsion angle of 107.4 (3)°. In the case of riluzole, the torsion angles of the four different molecules in the asymmetric unit show that in three cases the trifluoromethoxy group is perpendicular to the riluzole molecular plane and only in one molecule does the –OCF3 group lie in the same molecular plane. The crystal structure of riluzole primarily consists of strong N—H...N hydrogen bonds along with weak C—H...F, C—H...S, F...F, C...C and C...S interactions, while that of its salt is stabilized by strong [N—H]+...Cl− and weak C—H...Cl−, N—H...S, C—H...F, C...C, S...N and S...Cl− interactions.
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spelling doaj.art-507ab40c20094f2ab79a00e6c457485d2022-12-22T04:09:38ZengInternational Union of CrystallographyActa Crystallographica Section E: Crystallographic Communications2056-98902019-08-017581084108910.1107/S2056989019009022xi2017Crystal structure analysis of the biologically active drug molecule riluzole and riluzolium chloridePradip Kumar Mondal0Athulbabu T1Varun Rao2Deepak Chopra3Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhauri, Bhopal 462066, IndiaDepartment of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhauri, Bhopal 462066, IndiaDepartment of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhauri, Bhopal 462066, IndiaDepartment of Chemistry, Indian Institute of Science Education and Research, Bhopal, Bhauri, Bhopal 462066, IndiaThis study is an investigation into the crystal structure of the biologically active drug molecule riluzole [RZ, 6-(trifluoromethoxy)-1,3-benzothiazol-2-amine], C8H5F3N2OS, and its derivative, the riluzolium chloride salt [RZHCl, 2-amino-6-(trifluoromethoxy)-1,3-benzothiazol-3-ium chloride], C8H6F3N2OS+·Cl−. In spite of repeated efforts to crystallize the drug, its crystal structure has not been reported to date, hence the current study provides a method for obtaining crystals of both riluzole and its corresponding salt, riluzolium hydrochloride. The salt was obtained by grinding HCl with the drug and crystallizing the obtained solid from dichloromethane. The crystals of riluzole were obtained in the presence of l-glutamic acid and d-glutamic acid in separate experiments. In the crystal structure of RZHCl, the –OCF3 moiety is perpendicular to the molecular plane containing the riluzolium ion, as can be seen by the torsion angle of 107.4 (3)°. In the case of riluzole, the torsion angles of the four different molecules in the asymmetric unit show that in three cases the trifluoromethoxy group is perpendicular to the riluzole molecular plane and only in one molecule does the –OCF3 group lie in the same molecular plane. The crystal structure of riluzole primarily consists of strong N—H...N hydrogen bonds along with weak C—H...F, C—H...S, F...F, C...C and C...S interactions, while that of its salt is stabilized by strong [N—H]+...Cl− and weak C—H...Cl−, N—H...S, C—H...F, C...C, S...N and S...Cl− interactions.http://scripts.iucr.org/cgi-bin/paper?S2056989019009022crystal structureriluzolemolecular saltweak interactionselectrostatic potential
spellingShingle Pradip Kumar Mondal
Athulbabu T
Varun Rao
Deepak Chopra
Crystal structure analysis of the biologically active drug molecule riluzole and riluzolium chloride
Acta Crystallographica Section E: Crystallographic Communications
crystal structure
riluzole
molecular salt
weak interactions
electrostatic potential
title Crystal structure analysis of the biologically active drug molecule riluzole and riluzolium chloride
title_full Crystal structure analysis of the biologically active drug molecule riluzole and riluzolium chloride
title_fullStr Crystal structure analysis of the biologically active drug molecule riluzole and riluzolium chloride
title_full_unstemmed Crystal structure analysis of the biologically active drug molecule riluzole and riluzolium chloride
title_short Crystal structure analysis of the biologically active drug molecule riluzole and riluzolium chloride
title_sort crystal structure analysis of the biologically active drug molecule riluzole and riluzolium chloride
topic crystal structure
riluzole
molecular salt
weak interactions
electrostatic potential
url http://scripts.iucr.org/cgi-bin/paper?S2056989019009022
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AT athulbabut crystalstructureanalysisofthebiologicallyactivedrugmoleculeriluzoleandriluzoliumchloride
AT varunrao crystalstructureanalysisofthebiologicallyactivedrugmoleculeriluzoleandriluzoliumchloride
AT deepakchopra crystalstructureanalysisofthebiologicallyactivedrugmoleculeriluzoleandriluzoliumchloride