The syntheses and crystal structures of five 2-benzylidene-1-benzosuberone [1-benzosuberone is 6,7,8,9-tetrahydro-5H-benzoannulen-5-one] derivatives, viz. 2-(4-methoxybenzylidene)-1-benzosuberone, C19H18O2, (I), 2-(4-ethoxybenzylidene)-1-benzosuberone, C20H20O2, (II), 2-(4-benzylbenzylidene)-1-benzosuberone, C25H22O2, (III), 2-(4-chlorobenzylidene)-1-benzosuberone, C18H15ClO, (IV) and 2-(4-cyanobenzylidene)-1-benzosuberone, C19H15NO, (V), are described. The conformations of the benzosuberone fused six- plus seven-membered ring fragments are very similar in each case, but the dihedral angles between the fused benzene ring and the pendant benzene ring differ somewhat, with values of 23.79 (3) for (I), 24.60 (4) for (II), 33.72 (4) for (III), 29.93 (8) for (IV) and 21.81 (7)° for (V). Key features of the packing include pairwise C—H⋯O hydrogen bonds for (II) and (IV), and pairwise C—H⋯N hydrogen bonds for (V), which generate inversion dimers in each case. The packing for (I) and (III) feature C—H⋯O hydrogen bonds, which lead to  and  chains, respectively. Weak C—H⋯π interactions consolidate the structures and weak aromatic π–π stacking is seen in (II) [centroid–centroid separation = 3.8414 (7) Å] and (III) [3.9475 (7) Å]. A polymorph of (I) crystallized from a different solvent has been reported previously [Dimmock et al. (1999[Dimmock, J. R., Kandepu, N. M., Nazarali, A. J., Kowalchuk, T. P., Motaganahalli, N., Quail, J. W., Mykytiuk, P., Audette, G. F., Prasad, L., Perjési, P., Allen, T. M., Santos, C. L., Szydlowski, J., De Clercq, E. & Balzarini, J. (1999). J. Med. Chem. 42, 1358-1366.]) J. Med. Chem. 42, 1358–1366] in the same space group but with a packing motif based on inversion dimers resembling that seen in (IV) in the present study. The Hirshfeld surfaces and fingerprint plots for (I) and its polymorph are compared and structural features of the 2-benzylidene-1-benzosuberone family of phases are surveyed.
|Number of pages||7|
|Journal||Acta Crystallographica Section E: Crystallographic Communications|
|Early online date||29 Oct 2019|
|Publication status||Published - Nov 2019|
- crystal structure
- Crystal structure