Carboxylic acid derivatives


Carboxylic acid derivatives are formed by substitution of  -OH group of carboxylic acids by -X, -OR or -NH2 .So, there are four carboxylic acid derivatives. These are generally represented as R – C – Z, where Z is halogen (usually Cl), OCOR', OR' or NH2 (or NHR' or NR2'). 

·      When Z is halogen (usually Cl), the derivatives are called as acid chlorides i.e.RCOCl

·      When Z is —OR', the derivatives are called as esters i.e. RCOOR’       

·      When Z is – O – C – R', the derivatives are called carboxylic anhydrides i.e. (RCO)2O

·      Where Z is — NH2, the derivatives are called amides. i.e. RCONH2

·      When Z is –NHR' or –NR2'they are called N – substituted amides i.e. RCONHR


Nomenclature of Carboxylic Acid Derivatives
Acid Halides; Y = halogen, X;  RCOX
Change the -ic to -yl followed by the halide (e.g., acetyl chloride).

·         Acid Anhydrides; Y = acyl group;  RCO2COR
Symmetrical anhydrides of unsubstituted monocarboxylic acids and cyclic anhydrides of dicarboxylic acids are named by replacing the word acid with anhydride (e.g., acetic anhydride).
If the anhydride is derived from a substituted monocarboxylic acid, it is named by adding the prefix bis- (meaning two) to the acid name.   Unsymmetrical (mixed): give the name of the two acids followed by anhydride as a third word.

·         Amides; Y = NH2, NHR, or NR2;   RCONH2
Unsubstituted amides are named by replacing -oic with -amide or by replacing -carboxylic acid with -carboxamide.  Substituted nitrogen atoms are named by first identifying the substituent groups and then the parent amide name.  Nitrogen substituents are preceded by the letter N to identify them as bonded directly to nitrogen.

·         Esters, Y = OR;  RCO2R’
Using two separate words, identify the alkyl group attached to the oxygen and then the carboxylic acid, with the -ic ending replaced with -ate.

·         Nitriles,  RCN
Simple acyclic nitriles are named by adding -nitrile as a suffix to the alkane name, with the nitrile carbon number C1.



Carboxylic acid derivative reaction

1.    Hydrolysis: Reaction with water to yield a carboxylic acid.
            RCOY + H2O ----> RCO2H
2.    Alcoholysis: Reaction with an alcohol to yield an ester.
            RCOY + R’OH ----> RCO2R’
3.    Aminolysis: Reaction with ammonia or an amine to yield an amide.
            RCOY + NH3 ----> RCONH2
4.    Reduction: Reaction with a hydride reducing agent to yield an aldehyde or alcohol.
            RCOY + [H] ----> RCHO + [H] ----> RCH2OH
5.    Grignard: Reaction with an organometallic reagent to yield a ketone or an alcohol.
            RCOY + R’MgX ----> RCOR’ + R’MgX ----> RCOH(R’)2