Pregnenolone

Other Names: 3β-Hydroxypregn-5-en-20-one, Pregn-5-en-3β-ol-20-one
Chemical Formula: C₂₁H₃₂O₂
Molar Mass: 316.48 g/mol
CAS Number: 145-13-1
Appearance: White crystalline powder
Odor: Not specified in the reviewed scientific publications.

Pregnenolone is a C21 steroid characterized by a tetracyclic steroid framework, a hydroxyl group at the 3β-position, a carbonyl group at C20 and a double bond within the steroid nucleus. Its molecular formula, molar mass and CAS number are reported in scientific studies investigating its physicochemical and analytical properties. In biological steroidogenesis, pregnenolone is formed from cholesterol and serves as a central intermediate in steroid biosynthetic pathways. The compound has also attracted interest in solid-state and solution chemistry. Recent experimental research has investigated its polymorphic forms, solid–liquid equilibrium and solvent-dependent solubility, while other studies have examined its molecular interactions in model systems. Its defined steroidal structure and reactive functional groups additionally make pregnenolone a useful starting scaffold for chemical modification and the synthesis of structurally diverse steroid derivatives.

Chemical and physical properties

Pregnenolone is a crystalline steroid with the molecular formula C₂₁H₃₂O₂ and a molar mass of 316.48 g/mol. Experimental solid–liquid equilibrium studies describe the compound as a white crystalline powder and demonstrate that its solubility depends strongly on the solvent and solid-state form. Pregnenolone exhibits polymorphism, which is relevant to studies of crystallization, phase behavior and thermodynamic properties.

The molecule contains both hydroxyl and ketone functionalities within a rigid steroidal framework. Differences in molecular packing and intermolecular interactions have been investigated to explain the distinct solid-state behavior of structurally related steroids such as pregnenolone and progesterone.

Applications

Pregnenolone is used as a reference compound and analytical standard in steroid analysis. It has been included in quantitative methods based on UHPLC–MS/MS, LC–MS/MS and NMR spectroscopy for the identification and quantitative determination of steroid compounds.

In organic and synthetic chemistry, pregnenolone serves as a steroidal starting scaffold for structural modification. Published studies describe its use in the preparation of derivatives modified at different positions of the steroid framework, including ester, carbonyl and other functionalized derivatives.

Pregnenolone is also used in biochemical and metabolic research as a model substrate for investigating steroid biosynthesis, enzymatic transformations and microbial steroid conversion processes.

Safety

Not classified as dangerous according to WE 1272/ 2008 (CLP)