# Heterocycles

## Definition

A heterocycle is an organic compound whose carbon ring contains one or more heteroatoms ($O$, $S$, $N$ ...)

Nicotine

## Scientific Nomenclature

The body of the name refers to (in order of precedence!) the heteroatoms:

The suffix denotes the ring size:

## Examples

Oxetane

Thiepine

The order $O \gt S \gt N$ is for the body of the name and the numbering!

## Examples

1,2,4-Triazine

1,2,4-Oxathiazinane

If the cycle contains the maximum possible double bonds (completely unsaturated), hydrogen attached to an atom bound by two single bonds should be indicated with the prefix H

## Examples

1- H -azirine

2- H -azirine

If the cycle does not contain the maximum possible double bonds, the hydrogen atoms attached to two ring atoms bound by single bonds are indicated by the prefixes dihydro , trihydro ... The rest of the name is the name of the cycle with the maximum possible double bonds.

## Examples

2,3-Dihydroazete

2,3,4-Trihydrothiine

## Usual nomenclature

In the case of simple molecules the traditional names are preferred:

See →    here: