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Seven 3-methylidene-1H-indol-2(3H)-ones related to the multiple-receptor tyrosine kinase inhibitor sunitinib

Acta Cryst. (2010). C66, o71–o78 (doi.org/10.1107/S0108270109054134)

[Indolone hydrogen bonding]

The structural features of the compounds presented in the solid state correlate strongly with those found in solution. For example, stereoisomer characterisation [(E)- or (Z)-] and the presence of intramolecular hydrogen bonding are confirmed by both techniques although the X-ray study reveals extended intermolecular hydrogen bonding, which is not observed in solution-based techniques (1H NMR). The predominant motif in the crystal structures is that of intermolecular hydrogen bonding (N–H…O=C) between the 1H-indol-2(3H)-one units. This motif is maintained in the one structure that contains a hydrogen-bonding hydrate molecule. However, one structure, methyl 3-(1-methylethylidene)-2-oxo-2,3-dihydro-1H-indole-1-carboxylate, a carbamate analogue lacking an N–H bond, displays no intermolecular hydrogen bonding.

J. Spencer, B. Z. Chowdhry, S. Hamid, A. P. Mendham, L. Male, S. J. Coles and M. B. Hursthouse
28 April 2010