The title molecule, C21H25NO7, has four Bag stereogenic centres and crystallized as a racemate.It consists of enantiomeric pairs with the relative configuration rac-(1R*,2S*,3R*).The cyclohexenone ring adopts an envelope conformation; the dimethyl-substituted C atom lies 0.
640 (1) Å out of the mean plane formed by the rest of the ring atoms (r.m.s.
deviation = 0.016 Å).The oxacyclohexene ring adopts a half-chair conformation, the hydroxy- and carboxyl-substituted C atoms lying −0.
336 (1) and 0.419 (1) Å, respectively, out of Wedding Card the mean plane formed by the rest of the ring atoms (r.m.
s.deviation = 0.002 Å).
In the crystal, O—H.O hydrogen bonds link the molecules into a chain along the c-axis direction.