Nomenclature of natural products

The nomenclature of natural products is a specialised part of chemical nomenclature. The term "natural products" has a distinct meaning in "natural product chemistry": it does not usually include carbohydrates, peptides and proteins or nucleic acids, which have their own specific nomenclatures. The three main groups of natural products are alkaloids, steroids, and terpenes and terpenoids, although some natural products (e.g., many antibiotics) fall out side these main classes.

Nomenclature operations

Skeletal modifications

nor-

the removal of an unsubstituted skeletal atom (with its attached hydrogen atom(s), if any) from a ring or an acyclic portion of a fundamental parent structure.

homo-

the addition of a methylene group between two skeletal atoms of a fundamental parent structure.

cyclo-

the formation of an additional ring by means of a direct link between any two atoms of the fundamental parent structure.

seco-

the cleavage of a ring bond (saturated or unsaturated) with the addition of the appropriate number of hydrogen atoms at each new terminal group so created.

abeo-

the migration of one end of a single bond in the fundamental parent structure; the notation is X(Y→Z)-abeo-, where X is the locant that remains unchanged, Y is the locant of the other end of the single bond in the defined fundamental parent structure and Z is the locant of the end of the single bond in the modified structure.

retro-

in carotenoid nomenclature, the migration by one position of all single and double bond in a conjugated system; the notation is X,Y-retro-, where X is the locant of the atom that has lost a hydrogen atom in the bond migration and Y is the locant of the atom which has gained a hydrogen atom.

des-

the removal of a terminal ring from the defined fundamental parent structure, most commonly used in steroid nomenclature.