Structure and Nomenclature of Steroids

Abstract

A formula of a steroid compound is easily recognized by its four-membered hydrocarbon core (Fig. 1.1a). My little grand daughter called it "a little cottage", more advanced beginners may recall the term "cyclopentenoperhydrophenanthrene". All the thousands of natural and synthetic steroids are derivatives of that core. Ring A is the cyclohexane ring on the left; it is attached to another six-membered ring B. The C ring follows, the D ring is a cyclopentane system. Numbering of the core is shown in the most prolific steroid-cholesterol (Fig. 1.1b): it starts at the A ring, continues at B, C, and then D rings. Methyl groups at angular positions 13 and 10 are ascribed numbers 18 and 19, the numbering then continues in the side chain. The numbers are used to describe positions at which substituents or multiple bonds are attached in individual compounds. Most steroid compounds are derived from the following six basic hydrocarbons:

Rapid Self-Healing and Thixotropic Organogelation of Amphiphilic Oleanolic Acid–Spermine Conjugates

“…66 They are precursors for steroids, which compounds, contrary to triterpenoids, are characterized by at least 17 carbon atoms and bear tetracyclic systems with three six-membered rings (A, B, and C) and a five-membered ring (D). 67 This class of compounds, including cholesterol (a sterol), and bile acids, has already been extensively studied for their self-assembly and gelation properties. 1−5,10,26−32 Oleanolic acid [(3β)-3-hydroxyolean-12-en-28-oic acid, 1] is a pentacyclic triterpenoid (Figure 1) found throughout the plant kingdom in more than 120 plant species, of which especially in Panax ginseng root and Sambucus chinensis (Chinese elder) in high concentrations.…”

“…Triterpenoids, being structurally different from steroids, are a class of triterpenes, compounds with 30 carbon atoms, either in linear structure or fused rings, but containing additional heteroatoms or functional groups . They are precursors for steroids, which compounds, contrary to triterpenoids, are characterized by at least 17 carbon atoms and bear tetracyclic systems with three six-membered rings (A, B, and C) and a five-membered ring (D) . This class of compounds, including cholesterol (a sterol), and bile acids, has already been extensively studied for their self-assembly and gelation properties. − ,,− …”

Prospective Leads from Endophytic Fungi for Anti-Inflammatory Drug Discovery

“…Ten compounds containing cyclopentanoperhydrophenanthrene as the basic nucleus (i.e., steroids [56]) had been reported from endophytic fungi, which belong to different genus. They were ergosterol-3-O-β-D-glucopyranoside (37), 5α,8α-epidioxyergosta-6,22-dien-3β-ol (38), 3β,5α-dihydroxy-6β-methoxy ergosta-7,22diene (39), phomopsterone B (40), β-sitosterol (41), β-sitosterone (42), 5α,8α-epidioxyergosta-6,9(11),22-trien-3-ol (43), 5α,8αepidioxy-(22E,24 R)-23-methylergosta-6,22-dien-3β-ol (44), and fusaristerol A and B (45-46) (▶ Fig.…”

Direct Production of Bio-Recalcitrant Carboxyl-Rich Alicyclic Molecules Evidenced in a Bacterium-Induced Steroid Degradation Experiment

“…Steroids are a series of compounds with the structure of a four-membered hydrocarbon core (perhydrocyclopentanophenanthrene) ( 16 ). Within this, ring A is a cyclohexane ring on the left; it is attached to another six-membered ring, ring B.…”