A 3,5-dinitro­benzoyl derivative of a stereoisomer of glycerol menthonide

The title compound, [(2S,5R,6S,9R)-6-isopropyl-9-methyl-1,4-dioxaspiro­[4.5]dec-2-yl]methyl 3,5-dinitro­benzoate, C(20)H(26)N(2)O(8), was synthesized as part of a study of three-carbon stereochemical systems. The crystallographic assignment of the absolute stereochemistry is consistent with having started with (−)-menthone, the acetal carbon is R and the secondary alcohol is S. This brings the dinitro­benzoate into approximately the same plane as the menthyl ring and anti to the isopropyl group. Close inter­molecular C=O⋯NO(2) contacts between neighboring mol­ecules [2.8341 (16) Å] contribute to the packing arrangement. The structure was refined as a pseudo-merohedral twin (monoclinic space group P2(1) emulating the ortho­rhom­bic space group C222(1)). Application of the twin law 100, 0[Image: see text]0, [Image: see text]0[Image: see text] gave a 2:1 ratio of twin moieties [refined BASF value = 0.3790 (7)].