3-(3,4-Dimeth­oxy­benz­yl)chroman-4-one

In the title compound, C₁₈H₁₈O₄, the six-membered chroman-4-one ring adopts an envelope conformation with the C atom bonded to the bridging CH₂ atom as the flap. The dihedral angle between the mean plane of the fused pyranone ring and the dimeth­oxy-substituted benzene ring is 89.72 (2)°. In the crystal, adjacent molecules are linked via C—H...π inter­actions.

Ethyl 5-bromo-3-eth­oxy­carbonyl­amino-1-benzofuran-2-carboxyl­ate

In the title compound, C₁₄H₁₄BrNO₅, the ester group is disordered [occupancy ratio 0.52 (2):0.48 (2)]. The major component is nearly coplanar with the benzofuran plane, subtending a dihedral angle of 7.84 (2)°, while the amide group is twisted out of the benzofuran plane making a dihedral angle of 39.69 (2)°. An intra­molecular N—H...O hydrogen bond occurs. In the crystal, pairs of weak C—H...O hydrogen bonds link the mol­ecules into inversion dimers, which are further linked via strong N—H...O hydrogen bonds, generating a zigzag chain extending along [100].

Ethyl 3-amino-5-bromo-1-benzo­furan-2-carboxyl­ate

The title compound, C₁₁H₁₀BrNO₃, is close to planar with the benzo­furan unit and the ester group subtending a dihedral angle of 5.25 (2)°. The mol­ecular structure features an intra­molecular N—H...O inter­action. In the crystal, N—H...O hydrogen bonds involving carboxyl O-atom acceptors generate a chain extending along [201].

rac-3-(4-Hy­droxy­benz­yl)chroman-4-one

In the racemic title compound, C₁₆H₁₄O₃, the ring of the 4-hy­droxy­benzyl substituent group forms a dihedral angle of 80.12 (12)° with the benzene ring of the chromanone system. Two C atoms of the pyran­one ring and the H atoms on the benzyl α-C atom are disordered over two sites, with site-occupation factors of 0.818 (8) and 0.182 (8). The crystal structure is stabilized by O—H...O hydrogen bonds, which form parallel one-dimensional zigzag chains down the c axis and are inter­connected by both methine C—H...O hydrogen bonds and weak aromatic C—H...π inter­actions, giving a sheet structure lying parallel to [011].