Abstract
The 21-palmitate of the stereochemically pure glucocorticosteroid rofleponide [(22__R__)-6__α__,9__α__-difluoro-11__β__,21-dihydroxy-16__α__,17__α__-propylmethylenedioxypregn-4-ene-3,20-dione], C~41~H~64~O~7~F~2~, was synthesised, and its solid-state conformation and absolute configuration were determined at T = 163 ± 2 K using single-crystal X-ray diffraction. The structure has an orthorhombic (P__2~1~2~1~2~1~, No. 19) unit cell with a = 8.007(2) Å, b = 17.399(5) Å, c = 27.927(6) Å, V
~c~ = 3891(2) Å^3^, containing four molecules [D
~c~ = 1.2069(5) g cm^−3^, F(000) = 1536]. The R configuration for the chiral centre at C(22), created during the synthesis of rofleponide, is deduced using the knowledge of the absolute configuration of the hydrocortisone-related part of the molecule. The long-chained angular 17__β-substituent is partially disordered, exhibiting at least two different conformations: it is approximately equatorially connected to the cyclopentane D ring and axially to the dioxolane E ring in the ‘a’ conformer, but has a bisectional attachment to both five-membered rings in the ‘b’ conformer. The O(11)H···O(3) hydrogen bond links the steroid molecules so as to form endless parallel strings. The final structure model, comprising two major disorder sites for each of the eleven most disordered non-hydrogen atoms and also for the hydrogens linked to them, was refined to R = 0.061 for 1332 observations with I > 2__σ__(I).