3-{(E)-[4-(4-Hy­droxy-3-meth­oxy­phen­yl)butan-2-yl­idene]amino}-1-phenyl­urea: crystal structure and Hirshfeld surface analysis

Two independent mol­ecules (A and B) comprise the asymmetric unit of the title compound, C(18)H(21)N(3)O(3). The urea moiety is disubstituted with one amine being linked to a phenyl ring, which is twisted out of the plane of the CN(2)O urea core [dihedral angles = 25.57 (11) (A) and 29.13 (10)° (B)]. The second amine is connected to an imine (E conformation), which is linked in turn to an ethane bridge that links a disubstituted benzene ring. Intra­molecular amine-N—H⋯N(imine) and hydroxyl-O—H⋯O(meth­oxy) hydrogen bonds close S(5) loops in each case. The mol­ecules have twisted conformations with the dihedral angles between the outer rings being 38.64 (81) (A) and 48.55 (7)° (B). In the crystal, amide-N—H⋯O(amide) hydrogen bonds link the mol­ecules A and B via an eight-membered {⋯HNCO}(2) synthon. Further associations between mol­ecules, leading to supra­molecular layers in the ac plane, are hydrogen bonds of the type hydroxyl-O—H⋯N(imine) and phenyl­amine-N—H⋯O(meth­oxy). Connections between layers, leading to a three-dimensional architecture, comprise benzene-C—H⋯O(hy­droxy) inter­actions. A detailed analysis of the calculated Hirshfeld surfaces shows mol­ecules A and B participate in very similar inter­molecular inter­actions and that any variations relate to conformational differences between the mol­ecules.