Which of the following does not give claisen condensation reaction :

Options

A. `C_(6)H_(5)COOC_(2)H_(5)`
B. `C_(6)H_(5)CH_(2)COOC_(2)H_(5)`
C. `CH_(3)COOC_(2)H_(5)`
D. None of the above

Answer

To determine which of the given compounds does not undergo Claisen condensation, we need to analyze each compound for the presence of alpha hydrogen atoms. The Claisen condensation reaction requires at least one of the reactants to have alpha hydrogen atoms.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- A: C6H5COOC2H5 (Ethyl benzoate)
- B: CH2(COOC2H5) (Ethyl acetoacetate)
- C: CH3COOC2H5 (Ethyl acetate)
- D: C6H5CH2COOC2H5 (Benzyl acetate)

2. **Analyze Compound A (C6H5COOC2H5)**:
- Structure: C6H5-C(=O)-O-C2H5
- The carbonyl carbon (C=O) does not have any alpha hydrogen atoms because the phenyl group (C6H5) does not have any hydrogen atoms attached to the carbon adjacent to the carbonyl carbon.
- Conclusion: **Does not undergo Claisen condensation**.

3. **Analyze Compound B (CH2(COOC2H5))**:
- Structure: CH2-C(=O)-O-C2H5
- The carbon adjacent to the carbonyl (C=O) has two alpha hydrogen atoms (the CH2 group).
- Conclusion: **Undergoes Claisen condensation**.

4. **Analyze Compound C (CH3COOC2H5)**:
- Structure: CH3-C(=O)-O-C2H5
- The carbon adjacent to the carbonyl has three alpha hydrogen atoms (the CH3 group).
- Conclusion: **Undergoes Claisen condensation**.

5. **Analyze Compound D (C6H5CH2COOC2H5)**:
- Structure: C6H5-CH2-C(=O)-O-C2H5
- The carbon adjacent to the carbonyl has two alpha hydrogen atoms (the CH2 group).
- Conclusion: **Undergoes Claisen condensation**.

### Final Answer:
The compound that does not give Claisen condensation reaction is **A: C6H5COOC2H5**.