Question

OH Diclofenac Identify all the functional groups. For each functional group must be given an example of a characteristic reaction.

Answer 1

The functional groups present are:

1. Carboxylix acid: -COOH

Characteristic reaction: nucleophilic substitution reaction where the nucleophile (-OH) is substituted by another nucleophile (Nu).

Example: R-COOH + SOCl2  $\rightarrow$ RCOCl

2. Amine: -NHR2 (a secondary aromatic amine)

Characteristic reaction: Reaction with Nitrous Acid, HNO2 ,

Example: Secondary amines (aliphatic or aromatic) reacts with HONO to form Nitrosamines:

(Ar/R)2NH + HONO  $\rightarrow$ (Ar/R)2-N-NO

3. Phenyl group: -Ph ; that is the benzene ring Or, substituted benzene

Characteristic reaction: electrophilic substitution reaction where a hydrogen of a ring is substituted by an electrophile.

Example: Ph-H + R-Cl + AlCl3 $\rightarrow$ Ph-R   ; Friedel crafts alkylation

4. *Chloro : -Cl, Note that nucleophilic substitution reaction is the characteristic reaction of aliphatic halides :R-Cl

Example
R-Cl+ Nu- $\rightarrow$ R-Nu + Cl-

*But, when R is aromatic, as in this case an aryl halide, They are relatively unreactive toward nucleophilic substitution reactions; and mainly electrophilic substitution reactions occur in such case, with -Cl group acting as -ortho, -para directing to incoming electrophile.