Butanediol

Butanediol, also called butylene glycol, may refer to any one of four stable structural isomers:


 * 1,2-Butanediol
 * 1,3-Butanediol
 * 1,4-Butanediol
 * 2,3-Butanediol

Geminal diols
There are also two geminal diols (gem-diols), which are less stable:
 * 1,1-Butanediol, hydrate of butanal
 * 2,2-Butanediol, hydrate of butanone

Isobutylene glycol and methylpropanediol
Isobutylene glycol may be considered a kind of butylene glycol, similarly to butane historically including n-butane and i-butane (isobutane). The modern name for the closely related type of compounds is methylpropanediol. There are two stable structural isomers: and one unstable geminal diol: These three methylpropanediols are structural isomers of butanediols. They are not chiral.
 * 2-methylpropane-1,2-diol
 * 2-methylpropane-1,3-diol
 * 2-methylpropane-1,1-diol (not a glycol), hydrate of 2-methylpropanal (isobutyraldehyde)

Examples
2-Methylpropane-1,3-diol derivatives:
 * Crisnatol, an experimental medication
 * 2-Methyl-2-propyl-1,3-propanediol, medication precursor and active metabolite