Carboxylic acids contain a carboxyl group (-COOH). They are named according to IUPAC rules with the suffix "oic acid". Esters are produced from a reaction between carboxylic acids and alcohols in the presence of an acid catalyst. The ester name indicates the parent acid and alcohol. Amides are derived from carboxylic acids by replacing the -OH group of the carboxyl with an -NH2 group. They are named by replacing the "oic acid" ending of the parent acid with "amide".