Open AccessCrystal Structure Study of ( E )‐3‐(4‐Nitrobenzyloxyimino)hexahydroazepin‐2‐one Using Synchrotron Radiation
Author(s) -
TranQui D.,
Raymond S.,
Pecaut J.,
Kvick Å.
Publication year - 1997
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049597000320
Subject(s) - synchrotron radiation , crystal structure , intermolecular force , crystal structure prediction , crystallography , crystal (programming language) , chemistry , hydrogen bond , synchrotron , molecular dynamics , physics , molecule , computational chemistry , nuclear physics , computer science , organic chemistry , programming language
NOHA, 3‐(4‐nitrobenzyloxyimino)hexahydroazepin‐2‐one, is a potent anticonvulsive agent. It occurs in two stereoisomers, the Z and E forms. ( E )‐NOHA is about 1.5 times more active than ( Z )‐NOHA. While accurate structural data are available for ( Z )‐NOHA, those for the E form have remained, until recently, highly speculative due to the lack of single crystals of suitable size for X‐ray analysis and to the instability of the E isomer under radiation exposure. For structure‐activity correlation purposes, efforts have been made to solve the crystal structure of the E isomer. Data collection from tiny needle crystals has been performed using synchrotron radiation. An initial molecular‐packing model of this compound was obtained by energy‐based and X‐ray data modelling and successfully refined by molecular‐dynamics methods: space group P 2 1 / c , a = 6.225 (5), b = 17.885 (5), c = 12.157 (5) Å, β = 92.35 (5)°, R ‐factor = 3.5% for 343 reflections. In this contribution the crystal and molecular structure of ( E )‐NOHA is reported and the role of the hydrogen bond acting as the driving force in the intermolecular assembly in the ( E )‐NOHA crystal is highlighted.