Ethyl (E)-2-(2,7-dimethyl-5-oxo-4H,5H-pyrano[4,3-b]pyran-4-ylidene)acetate

Abstract

In the title compound, C14H14O5, the two heterocyclic rings are coplanar (r.m.s. deviation = 0.008 Å), with the largest deviation from the mean plane being 0.012 (1) Å. The mean plane through the acetate group is inclined slightly with respect to the oxopyrano[4,3-b]pyran-4-yl system, as indicated by the dihedral angle of 1.70 (7)° between them. Two intramolecular hydrogen bonds, completing S(6) ring motifs, are observed in the molecule. In the crystal, molecules are linked by weak C—H...O hydrogen bonds involving the same acceptor atom, forming chains propagating along the c-axis direction and enclosing R21(6) ring motifs. The chains are linked via offset π–π interactions [intercentroid distance = 3.622 (1) Å], involving inversion-related oxopyrano[4,3-b]pyran-4-yl ring systems, forming slabs parallel to the bc plane.

Keywords

• crystal structure
• oxopyrano[4,3-b]pyran-4-ylidene
• heterocyclic compounds
• C—H...O hydrogen bonding
• offset π–π interactions