Addition of Ammonia Derivatives ($$NH_{2}-Z)$$ - Nucleophile addition reaction

Overall Reaction:

$$\text{R}_2\text{C=O} + \text{H}_2\text{N--Z} \xrightarrow{\text{H}^+ \text{ (pH } 3.5\text{--}4.5\text{)}} \text{R}_2\text{C=N--Z} + \text{H}_2\text{O}$$

Concept: Nucleophilic attack by a nitrogen derivative followed by continuous dehydration to form a carbon-nitrogen double bond. The environment must be strictly maintained at a weakly acidic pH of approximately $$3.5$$ to protonate the oxygen without completely deactivating the nucleophile.

Notation:

• $$\text{NH}_2\text{OH} \longrightarrow \text{Oximes}$$;
• $$\text{NH}_2\text{NH}_2 \longrightarrow \text{Hydrazones}$$;
• $$\text{2,4-DNP} \longrightarrow \text{2,4-Dinitrophenylhydrazone Derivative}$$.