amides

amides

organic molecules which contain a carbonyl to nitrogen single bond

amide bond

bond that breaks when amides are hydrolysed - amide bond is also called a peptide bond

physical properties

amides are quite polar and have very strong intermolecular forces - high BP

chemical properties

amides are not proton acceptors (bases)

the carbonyl attracts the lone pair on nitrogen to prevent it from bonding to H+

amide preparation

1. amines + carboxylic acids

2. amines + acid chlorides

amines + carboxylic acids

poor method of preparation

poor reactivity of carboxylate group towards nucleophilic substitution

amines + acid chlorides

works for primary amines, secondary amines and ammonia

leaving group (Cl-)

excess of amine to neutralise all HCl

acidic hydrolysis

amine product is converted into its ammonium salt

basic hydrolysis

carboxylic acid product is converted into its carboxylate salt

biological hydrolysis

enzymes catalyse amide hydrolysis - digestion of proteins

amide bonds are readily cleaved in the stomach - pectin