Tizzard, Graham J., Coles, Simon J., Edwards, Mark, Onyeabo, Romanus Oforbike, Allen, Mark and Spencer, John (2013) Synthesis and solid-state characterisation of 4-substituted methylidene oxindoles. Chemistry Central Journal, 7 (1):182. ISSN 1752-153X (doi:10.1186/1752-153X-7-182)

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Abstract

BACKGROUND: 4-substituted methylidene oxindoles are pharmacologically important. Detailed analysis and comparison of all the interactions present in crystal structures is necessary to understand how these structures arise. The XPac procedure allows comparison of complete crystal structures of related families of compounds to identify assemblies that are mainly the result of close-packing as well as networks of directed interactions.

RESULTS: Five 4-substituted methylidene oxindoles have been synthesized by the Knoevenagel condensation of oxindole with para-substituted aromatic aldehydes and were characterized in the solid state by x-ray crystallography. Hence, the structures of (3E)-3-(4-Bromobenzylidene)-1,3-dihydro-2H-indol-2-one, 3a, (3E)-3-(4-Chlorobenzylidene)-1,3-dihydro-2H-indol-2-one, 3b, (3E)-3-(4-Methoxybenzylidene)-1,3-dihydro-2H-indol-2-one, 3c, (3E)-3-(4-Methylbenzylidene)-1,3-dihydro-2H-indol-2-one, 3d and (3E)-3-(4-Nitrobenzylidene)-1,3-dihydro-2H-indol-2-one, 3e, were elucidated using single crystal X-ray crystallography.

CONCLUSIONS: A hydrogen bonded dimer molecular assembly or supramolecular construct was identified in all the crystal structures examined along with a further four 1D supramolecular constructs which were common to at least two of the family of structures studied. The 1D supramolecular constructs indicate that once the obvious strong interaction is satisfied to form hydrogen bonded dimer it is the conventionally weaker interactions, such as steric bulk and edge-to-face interactions which compete to influence the final structure formation.

Item Type:	Article
Additional Information:	[1] Acknowledgements (funding):The authors would like to thank EPSRC for funding the UK National Crystallography Service. [2] Copyright: © 2013 Tizzard et al.; licensee Chemistry Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Uncontrolled Keywords:	4-substituted methylidene oxindoles, Knoevenagel condensation, solid state x-ray crystallography
Subjects:	Q Science > QD Chemistry
Faculty / School / Research Centre / Research Group:	Faculty of Engineering & Science Faculty of Engineering & Science > School of Science (SCI) Faculty of Engineering & Science > Medway School of Pharmacy
Related URLs:	Publisher
Last Modified:	08 Nov 2019 13:29
URI:	http://gala.gre.ac.uk/id/eprint/13209

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