Reactions of Aldehydes & Ketones. Part II.

Lecture Notes: Reactions of Aldehydes & Ketones. Part II.

ACETAL FORMATION






















Non-aqueous acid shifts the equilibrium to the right (favors acetal) Aqueous acid shifts the equilibrium to the left (favors carbonyl)
ACETALS AS PROTECTING GROUPS

Characteristics of a Good Protecting Group: Must be easy to put on Alters the chemistry of the protected functionality Must be easy to remove




REACTION OF PRIMARY AMINES Nucleophilic Addition-Elimination












2,4-DNP TEST Reaction of the carbonyl functionality of an aldehyde or ketone with 2,4-DNP (2,4-dinitrophenylhydrazine) yields a yellow, orange, or red precipitate. This is a simple chemical test to detect the presence of aldehyde or ketone carbonyl. The carbonyls of carboxylic acids, esters, acid halides and amides do not give positive tests.

REACTION WITH SECONDARY AMINES Enamines