Aldol

In organic chemistry, an aldol describes a structural motif consisting of a 3-hydroxy ketone, R−CH(OH)−CHR'−C(=O)−R", or 3-hydroxyaldehyde, R−CH(OH)−CHR'−CH=O. Both are composed of a hydroxy group (−OH) and either a ketone (>C=O) or an aldehyde (−CH=O, which is merely a ketone with a hydrogen substituent). An aldol consisting of a 3-hydroxy ketone is called a β-hydroxy ketone, and an aldol consisting of a 3-hydroxy aldehyde is called a β-hydroxy aldehyde. The term "aldol" may refer to 3-hydroxybutanal.