Crystal structure of (3E)-3-(2,4-di­nitro­phen­oxy­meth­yl)-4-phenyl­but-3-en-2-one

In the title compound, C₁₇H₁₄N₂O₆, the conformation about the C=C double bond [1.345 (2) Å] is E, with the ketone moiety almost coplanar [C—C—C—C torsion angle = 9.5 (2)°] along with the phenyl ring [C—C—C—C = 5.9 (2)°]. The aromatic rings are almost perpendicular to each other [dihedral angle = 86.66 (7)°]. The 4-nitro moiety is approximately coplanar with the benzene ring to which it is attached [O—N—C—C = 4.2 (2)°], whereas the one in the ortho position is twisted [O—N—C—C = 138.28 (13)°]. The mol­ecules associate via C—H...O inter­actions, involving both O atoms from the 2-nitro group, to form a helical supra­molecular chain along [010]. Nitro–nitro N...O inter­actions [2.8461 (19) Å] connect the chains into layers that stack along [001].

Crystal structure of ethyl 2-[(4-bromo­phen­yl)amino]-3,4-di­methyl­pent-3-enoate

In the title compound, C₁₅H₂₀BrNO₂, there are two independent mol­ecules (A and B) comprising the asymmetric unit and these adopt very similar conformations. In A, the dihedral angle between the CO₂ and MeC=CMe₂ groups is 80.7 (3)°, and these make dihedral angles of 3.5 (3) and 84.09 (16)°, respectively, with the bromo­benzene ring. The equivalent dihedral angles for mol­ecule B are 78.4 (3), 2.1 (3) and 78.37 (12)°, respectively. The most prominent inter­actions in the crystal packing are amine-N—H...O(carbon­yl) hydrogen bonds between the two independent mol­ecules, resulting in non-centrosymmetric ten-membered {...OC₂NH}₂ synthons. Statistical disorder is noted for each of the terminal methyl groups of the ethyl residues.