5,17-Diformyl-25,26,27,28-tetra-propoxy-calix[4]arene.

The title compound, C42H48O6, was obtained via formyl-ation of 25,26,27,28-tetra-propoxycalix[4]arene with dichloro-methyl methyl ether and tin tetra-chloride. It adopts a pinched cone conformation, which leads to an open cavity. The two opposite aromatic rings bearing formyl groups are almost parallel, making a dihedral angle of 29.1 (2)°. The other pair of opposite rings are close to being perpendicular, making a dihedral angle of 73.6 (1)°. Adjacent rings are almost perpendicular, making dihedral angles of 78.8 (2), 81.6 (1), 78.2 (1) and 74.7 (1)°.