Question

Which one of the following compounds does not react with acetyl chloride?

• A. CH3CH2NH2
• B. CH3CH2CH2NHCH3
• C. (CH3CH2)3 N
• D. (CH3)3 CNH2

Answer 1

Answer: (C)

(CH₃CH₂)₃N

Answer 2

Acetyl chloride reacts with amines that have at least one replaceable N–H proton, allowing formation of an amide. Primary (RNH₂) and secondary (R₂NH) amines have available N–H bonds, while tertiary amines (R₃N) lack an N–H proton and hence cannot be acetylated.

• CH₃CH₂NH₂ is a primary amine and reacts.
• CH₃CH₂CH₂NHCH₃ is a secondary amine and reacts.
• (CH₃CH₂)₃N is a tertiary amine with no N–H proton, so it does not react.
• (CH₃)₃CNH₂ is a primary amine (despite steric hindrance) and can react.

Tertiary amines lack the N–H proton required for acetylation.