Crystal structure of 22,24,25-trimethyl-8,11,14-trioxa-25-aza-tetra-cyclo-[19.3.1.0(2,7).0(15,20)]penta-cosa-2,4,6,15(20),16,18-hexaen-23-one.

The title compound, C24H29NO4, is the product of a Petrenko-Kritchenko condensation of 1,5-bis-(2-formyl-phen-oxy)-3-oxa-pentane, pentan-3-one and methyl-ammonium acetate in ethanol. The mol-ecule has mirror symmetry. The aza-14-crown-3 ether ring adopts a bowl conformation stabilized by a weak intra-molecular C-H⋯O hydrogen bond. The conformation of the C-O-C-C-O-C-C-O-C polyether chain is t-g(+)-t-t-g(-)-t (t = trans, 180°; g = gauche, ±60°). The dihedral angle between the benzene rings fused to the aza-14-crown-4-ether moiety is 72.68 (4)°. The piperidinone ring adopts a chair conformation. The nitro-gen atom has a trigonal-pyramidal geometry, the sum of the bond angles being 335.9°. In the crystal, the mol-ecules are linked by weak C-H⋯O inter-actions, forming zigzag chains propagating along the [100] direction.