Benzyl N-(1-{N′-[(E)-2-chlorobenzylidene]hydrazinecarbonyl}-2-hydroxyethyl)carbamate

The molecule of the title compound, C18H18ClN3O4, is twisted about the chiral C atom with the dihedral angle between the two amide residues being 87.8 (5)°, but, overall, it can be described as curved, with the benzene rings lying on the same side of the molecule [dihedral angle = 62.8 (4)°]. The conformation about the imine bond [1.294 (7) Å] is E. In the crystal, a two-dimensional array in the ab plane is mediated by O—H⋯O and N—H⋯O hydrogen bonds as well as C—H⋯Cl interactions. The layers stack along the c-axis direction, being connected by C—H⋯.π contacts.

The molecule of the title compound, C 18 H 18 ClN 3 O 4 , is twisted about the chiral C atom with the dihedral angle between the two amide residues being 87.8 (5) , but, overall, it can be described as curved, with the benzene rings lying on the same side of the molecule [dihedral angle = 62.8 (4) ]. The conformation about the imine bond [1.294 (7) Å ] is E. In the crystal, a two-dimensional array in the ab plane is mediated by O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds as well as C-HÁ Á ÁCl interactions. The layers stack along the c-axis direction, being connected by C-HÁ Á Á. contacts.
The use of the EPSRC X-ray crystallographic service at the University of Southampton, England, and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES (Brazil).

Comment
Interest in the development of N-acylhydrazone derivatives from L-serine for use in anti-tumour testing Pinheiro et al., 2011a: Pinheiro et al., 2011bHowie et al., 2011) arises from the known anti-tumour activity of L-serine derivatives (Jiao et al., 2009;Yakura et al., 2007), and motivated the study of the title compound, (I).
Overall, the molecule of (I), Fig. 1, is curved with the benzene rings lying on the same side of the molecule. Nevertheless, the molecule is twisted about the chiral centre with the dihedral angle formed between the two amide residues, i.e. N2,C8,O1 and N3,C11,O3,O4, being 87.8 (5) °. The benzyl group is approximately co-planar with the carboxylate group with the dihedral angle between the carbamate group (N3,C11,O3,O4) and benzene ring (C13-C18) being 9.9 (2) °. By contrast, the benzene ring connected to the hydrazine group is twisted out of the plane through the latter as seen in the value of the C2-C1-C7-N1 torsion angle of 146.7 (5) °. The dihedral angle formed between the terminal benzene rings is 62.8 (4)°.
The conformation about the N1═C7 imine bond [1.294 (7) The crystal packing is dominated by hydrogen bonding interactions, Table 1. The hydroxyl group forms a O-H···O hydrogen bond with the carbamate-carbonyl group, and simultaneously accepts a hydrogen bond from carbamate-amine.
The hydrazine-amine forms a N-H···O hydrogen bond with the carbonyl adjacent to the hydrazine group. The result of the hydrogen bonds is the formation of a two-dimensional array in the ab plane, Fig. 2. Additional stabilization to the layer is afforded by C-H···Cl interactions, Table 1. Layers stack along the c direction and are connected via C-H···π interactions, Table 1 and Fig. 3.
The O-and N-bound H atoms were located from a difference map and refined with the distance restraints O-H = 0.84 ± 0.01 and N-H = 0.88±0.01 Å, and with U iso (H) = zU eq (carrier atom); z = 1.5 for O and z = 1.2 for N. Fig. 1. The molecular structure of (I) showing displacement ellipsoids at the 50% probability level.