21. Aldehydes and Ketones: Nucleophilic Addition

Predict the products formed when cyclohexanone reacts with the following reagents.

(a) CH₃NH₂, H⁺

Show how you would synthesize the following derivatives from appropriate carbonyl compounds.

(a) <IMAGE>

Predict the products formed when cyclohexanecarbaldehyde 

reacts with the following reagents.

(c) semicarbazide and weak acid

Show a complete mechanism for this reaction.

<IMAGE of reaction>

Show how you would synthesize the following derivatives

from appropriate carbonyl compounds.

(c) <IMAGE>

What are the products of the following reactions? (A trace amount of acid is present in each case.)

a. cyclopentanone + ethylamine

b. cyclopentanone + diethylamine

What aldehydes are formed when the following amino acids are treated with ninhydrin? 

b. leucine 

c. arginine

2,4-Dinitrophenylhydrazine is frequently used for making derivatives of ketones and aldehydes because the products (2,4-dinitrophenylhydrazones, called 2,4-DNP derivatives) are even more likely than the phenylhydrazones to be solids with sharp melting points. Propose a mechanism for the reaction of acetone with 2,4-dinitrophenylhydrazine in a mildly acidic solution.

Predict the major products of the following reactions. (a) <IMAGE of reaction>

Propose mechanisms for the following reactions. (b) <IMAGE of reaction>