5,17-Diethoxycarbonyl-25,26,27,28-tetrahydroxycalix[4]arene

The title compound, diethyl 25,26,27,28-tetrahydroxypentacyclo[19.3.1.1^3,7.1^9,13.1^15,19]octacosa-1(25),3,5,7(18),9,11,13 (27),15,17,19 (26),21,23-dodecaene-5,17-dicarboxylate, C₃₄H₃₂O₈, a tetrahydroxy calix[4]arene, adopts an open-cone conformation in the solid state; this conformation is dictated by the presence of intramolecular O-H...O hydrogen bonding of the phenolic OH groups [O...O 2.673 (2)–2.708 (2) Å]. The planes of the aromatic rings are inclined at 120.8 (1), 133.1 (1), 118.0 (1) and 128.5 (1)° to the plane of the methylene C atoms which link them. Self-inclusion occurs when the molecules assemble in pairs about inversion centres.

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