Key indicators: single-crystal X-ray study; T = 296 K; mean (C-C) = 0.003 Å; disorder in main residue; R factor = 0.053; wR factor = 0.141; data-to-parameter ratio = 17.7.The title compound, C 20 H 26 O 6 , is chiral and crystallizes as a racemate: the relative configuration of the stereogenic centres is 1R*,2R*,3S*,4R*. The cyclohexane ring has a chair conformation. The ethyl fragment of the ethoxycarbonyl group in the 3-position is disordered over two sets of sites in a 0.650 (6):0.350 (6) ratio. The hydroxy group acts as a bifurcated hydrogen-bond donor, forming both intra-and intermolecular hydrogen bonds with ester carbonyl O atoms. The intermolecular hydrogen bonds form inversion dimers in the crystal. Related literatureFor applications of related compounds as synthetic intermediates, see: Gein et al. (2003Gein et al. ( , 2004 Sorokin et al. (2000). ExperimentalCrystal data

The title compound, C18H22N2O3, represents a (4S,5R,6S)-stereoisomer, crystallizing as a racemate in a centrosymmetric space group. The six-membered aliphatic ring adopts a half-chair conformation, with the hy­droxy- and acetyl-substituted C atoms deviating by 0.458 (2) and −0.366 (2) Å, respectively, from the plane defined by other four ring atoms. The pyrazole ring is essentially planar [r.m.s deviation = 0.004 (2) Å]. In the crystal, the mol­ecules are linked into chains along the b axis by N—H⋯N hydrogen bonds. The chains are linked by O—H⋯N hydrogen bonds into layers parallel to the bc plane.