(E)-1-(Furan-2-yl)-3-(2,4,5-trimeth­oxy­phen­yl)prop-2-en-1-one

In the title chalcone derivative, C16H16O5, the dihedral angle between the furan and benzene rings is 2.06 (17)°. The two meth­oxy groups at the ortho and para positions are essentially coplanar with the benzene ring [C—O—C—C angles = −1.0 (5) and 178.5 (3)°], whereas the third one at the meta position is slightly twisted [C—O—C—C = 9.6 (5)°]. In the crystal, weak C—H⋯O inter­actions link the mol­ecules into a sheet parallel to (02). An inter­molecular π–π inter­action between the furan and benzene rings is present [centroid–centroid distance = 3.772 (2) Å]. A short C⋯C contact [3.173 (5) Å] is also observed between neighbouring furan rings

(E)-1-(4-Amino­phen­yl)-3-(pyridin-3-yl)prop-2-en-1-one

The title chalcone derivative, C14H12N2O, consists of 4-amino­phenyl and pyridine rings bridged by a prop-2-en-1-one unit and exists in a trans configuration with respect to the C=C double bond. The mol­ecule is slightly twisted with a dihedral angle of 29.38 (7)° between the benzene and pyridine rings. The prop-2-en-1-one bridge is nearly planar with an r.m.s. deviation of 0.0384 (1) Å and makes dihedral angles of 15.40 (9) and 16.30 (9)°, respectively, with the benzene and pyridine rings. In the crystal, mol­ecules are linked by N—H⋯N and N—H⋯O hydrogen bonds into a layer parallel to the ab plane. A π–π inter­action with a centroid–centroid distance of 3.6946 (10) Å is also observed

(E)-1-(2-Hydroxyphenyl)-3-(2,4,5-trimethoxyphenyl)prop-2-en-1-one

In the title chalcone derivative, C18H18O5, the dihedral angle between the hydroxy-substituted benzene ring and the trimethoxy-substituted benzene ring is 16.3 (1)°. The three methoxy groups are essentially coplanar with the benzene ring to which they are attached, with an r.m.s. deviation of 0.0208 Å. An intramolecular O—H...O hydrogen bond generates an S(6) ring motif. In the crystal, weak C—H...O interactions link molecules into helical chains along the b axis. These chains are connected into sheets parallel to the bc plane by further weak C—H...O interactions