Question

Which of the following amino compound(s) CANNOT be prepared by Gabriel phthalimide synthesis? 

(A) n-Butylamine 
(B) Alanine 
(C) Aniline 
(D) t-Butylamine 
Choose the correct answer from the options given below:

• A. (B) and (D) only
• B. (C) and (D) only
• C. (A) and (B) only
• D. (B), (C) and (D) only

Hint:

Gabriel phthalimide synthesis is effective for primary amines, but aromatic and bulky amines are not readily formed by this method.

Answer 1

The Correct Option is D

Step 1: Gabriel Phthalimide Synthesis Overview.
The Gabriel phthalimide synthesis is a method for preparing primary amines. It involves the reaction of phthalimide with an alkyl halide under strong base conditions, followed by hydrolysis. This method is generally effective for primary amine preparation, though it has limitations.

Step 2: Analysis of Options.
- (A) n-Butylamine: This can be synthesized via Gabriel phthalimide synthesis because the alkylation step is effective with primary alkyl halides.
- (B) Alanine: Alanine's synthesis is complicated by the presence of both an amino and a carboxyl group, and it involves a secondary amino group. Therefore, alanine cannot be synthesized using this method.
- (C) Aniline: Aniline is an aromatic amine. The Gabriel phthalimide synthesis is ineffective for preparing aromatic amines; thus, aniline cannot be prepared by this method.
- (D) t-Butylamine: The bulky tertiary-butyl group in t-butylamine prevents the alkylation step from proceeding effectively in the Gabriel synthesis. Consequently, t-butylamine cannot be synthesized by this method.

Step 3: Conclusion.
Accordingly, compounds (B), (C), and (D) cannot be prepared by Gabriel phthalimide synthesis.

Final Answer: \[\boxed{\text{(4) (B), (C) and (D) only}}\]