It is possible to convert a carboxylic acid derivative into another carboxylic acid derivative. The following rules apply: (1) Any carboxylic acid derivative is converted to a carboxylic acid upon hydrolysis; (2) A carboxylic acid can be converted to an acid chloride via reaction with thionyl chloride; (3) A more reactive carboxylic acid derivative can be converted directly into a less reactive carboxylic acid derivative via reaction with a suitable nucleophile. A reaction scheme that summarizes these rules is explained. Closed captions were generated automatically.