Cortexolone

Cortexolone or cortodoxone or 11-deoxycortisol or 11-desoxycortisol or 11-deoxyhydrocortisone or 11-desoxyhydrocortisone or Reichstein's Substance S or, most commonly, Compound S, is a steroid that can be oxygenated to cortisol (hydrocortisone). It was first synthesized by Tadeusz Reichstein.

On April 5, 1952, biochemist Durey Peterson and microbiologist Herbert Murray at Upjohn published the first report of a breakthrough fermentation process for the microbial 11α-oxygenation of steroids (e.g. progesterone) in a single step by common molds of the order Mucorales. 11α-oxygenation of Compound S produces 11α-hydrocortisone, which can be chemically oxidized to cortisone, or converted by further chemical steps to 11β-hydrocortisone (cortisol).

Subsequent fermentation processes for the microbial 11β-oxygenation of steroids in a single step were developed that could convert Compound S directly to 11β-hydrocortisone (cortisol).