Key Concepts In Organic Chemistry: Derivatives Of Carboxylic Acids
-All carboxylic derivatives are formed from a substitution reaction of a carboxylic acid. All carboxylic acid
derivatives have the acyl group in common.
-For esters, change the “-ic acid” to “ate,” preceded by the name of the alkyl group on the ester OR
group. Cyclic esters are called lactones and are designated σ, β, ϒ, δ, or ε depending on the number of
carbon atoms the ester O atom is from the C =O. Esters are used frequently in phosphoric acid as they
can make more ester bonds than carbon (mono-, di- or triphosphate esters). More variety is present
with phosphoric acid as opposed to carboxylic acids.
-For acid halides, change the “-ic acid” to “-yl halide.” For symmetrical anhydrides change “acid” to
“anhydride.” Anhydrides are formed by coupling two carboxylic acids with the loss of water and cyclic
anhydrides are easily formed by heating dicarboxylic acids (intramolecular reaction).
-For amides, change “-oic acid” or “-ic acid” to “amide.” If the N of the amide group bears groups other
than H, designate their attachment to the nitrogen by using the prefix “N” for each group. Amide bonds
that like α-amino acids together is known as a peptide bond. Cyclic amides are called lactams, and when
two acyl groups form amide bonds to the same N atom an imide results. *Remember that no sp
carbons can ever enter into resonance stabilization (no electron pairs). Lactams = cyclic amides, while
lactones = cyclic esters.
-All acid derivatives contain a strong C = O stretch in the normal 1630-1800cm region.
-*Acid chlorines are the most reactive of the acid derivatives and esters, anhydrides and amides are
usually made from acid chlorides.
-Acid derivatives can be interconverted one to another, and all can be converted to the parent
carboxylic acid by nucleophilic acyl substitution. This mechanism involves the addition of a Nu to the
C=O, followed by an elimination of the acyl substituent Y (acting as a LG). The mechanism of other acid-
catalyzed nucleophilic acyl substitution reactions differs from this general mechanism only in the nature
of the Nu.
-When writing mechanisms for all chemical reactions, anions (but not cations) are the allowed species in
basic conditions and cations (but not anions) are the allowed species in acidic conditions (base = anions
only; acid = cations only).