Crystal and molecular structure of cortisol (11β,17α,21-trihydroxypregn-4-ene-3,20-dione) methanol solvate

Abstract

Cortisol methanol solvate crystallises in the orthorhombic space group P2₁2₁2₁, with a= 14·372(4), b= 18·400(5), c= 7·706(2)Å, Z= 4. The structure was solved from diffractometer data by direct methods and refined to R 0·044 for 1908 observed reflexions.

Ring A is a distorted ‘sofa’, rings B and C are in the ‘chair’ configuration and ring D is close to a C(13) envelope, with a pseudorotational parameter Δ of 26·1°. The ring junctions B/C and C/D are both trans. The molecule as a whole is slightly convex towards the β-side, with an angle of 10·9° between the C(10)–C(19) and C(13)–C(18) vectors. The conformation of the C(17) side chain is compared with theoretical predictions based on MO and o.r.d. calculations.