(E)-2-({2-[(E)-(Hy-droxy-imino)-meth-yl]phen-oxy}meth-yl)-3-p-tolyl-acrylonitrile

Crystal structures and Hirshfeld surfaces of four meth-oxy-benzaldehyde oxime derivatives, 2-MeO-XC6H3C=NOH (X = H and 2-, 3- and 4-MeO): different conformations and hydrogen-bonding patterns

The crystal structures of four (E)-meth-oxy-benzaldehyde oxime derivatives, namely (2-meth-oxy-benzaldehyde oxime, 1, 2,3-di-meth-oxy-benzaldehyde oxime, 2, 4-di-meth-oxy-benzaldehyde oxime, 3, and 2,5-di-meth-oxy-benzaldehyde oxime, 4, are discussed. The arrangements of the 2-meth-oxy group and the H atom of the oxime unit are s-cis in compounds 1-3, but in both independent mol-ecules of compound 4, the arrangements are s-trans. There is also a difference in the conformation of the two mol-ecules in 4, involving the orientations of the 2- and 5-meth-oxy groups. The primary inter-molecular O-H(oxime)⋯O(hy-droxy) hydrogen bonds generate C(3) chains in 1 and 2. In contrast, in compound 3, the O-H(oxime)⋯O(hy-droxy) hydrogen bonds generate symmetric R 2 2(6) dimers. A more complex dimer is generated in 4 from the O-H(oxime)⋯O(hy-droxy) and C-H(2-meth-oxy)⋯O(hy-droxy) hydrogen bonds. In all cases, further inter-actions, C-H⋯O and C-H⋯π or π-π, generate three-dimensional arrays. Hirshfeld surface and fingerprint analyses are discussed.

8-Bromo-3-(4-ethyl-phen-yl)-1-phenyl-3,3a,4,9b-tetra-hydro-1H-chromeno[4,3-c]isoxazole-3a-carbo-nitrile

In the title compound, C25H21BrN2O2, the fused isoxazolidine ring adopts an envelope conformation with the N atom at the flap and the mean plane of the ring makes dihedral angles of 54.37 (12) and 87.32 (13)°, respectively, with the adjacent phenyl and benzene rings. The tetra-hydro-pyran ring has a half-chair conformation. In the crystal, mol-ecules are linked into a double-column structure along the b-axis direction through weak C-H⋯O and C-H⋯π inter-actions.

(E)-2-Bromo-methyl-3-(o-tol-yl)acrylo-nitrile

The title compound C11H10BrN, has an E conformation at the C=C bond of the acrylo-nitrile unit. The vinyl group makes a dihedral angle of 44.53 (12)° with the benzene ring. In the crystal, weak C-H⋯π inter-actions involving the benzene ring are observed.

(E)-2-[(2-Formyl-phen-oxy)meth-yl]-3-(4-iso-propyl-phen-yl)acrylo-nitrile

In the title compound, C20H19NO2, the dihedral angle between the benzene rings is 77.12 (8)°. The terminal isopropyl group is disordered over two orientations, with site occupancies of 0.720 (14) and 0.280 (14). In the crystal, mol-ecules are linked through a weak C-H⋯O inter-action, forming a zigzag chain along the c-axis direction.