What set of conditions would be useful for preparing a 2° amine?

Options

A. `2^(@) R - Br + NaNH_2`
B. `2^(@) R - Br + NaN_(3) , H_(2) // Pt`
C. `1^(@) R - NH_(2) + 1^(@) R CHO, H_(2) and Pt`
D.

Answer

To prepare a secondary amine, we can utilize the following steps based on the analysis of the provided options:

### Step-by-Step Solution:

1. **Understanding Secondary Amines**:
- A secondary amine is characterized by having a nitrogen atom bonded to two carbon groups and one hydrogen atom. The general structure is R2NH, where R represents carbon groups.

2. **Analyzing the Options**:
- We need to evaluate each option to determine which one can lead to the formation of a secondary amine.

3. **Option A**:
- The reaction involves a secondary alkyl bromide (R2Br) reacting with sodium amide (NaNH2).
- This reaction leads to the formation of a primary amine (RNH2) rather than a secondary amine.
- **Conclusion**: This option does not yield a secondary amine.

4. **Option B**:
- This option also involves a secondary alkyl bromide (R2Br) reacting with sodium azide (NaN3) followed by hydrogenation over platinum.
- The product formed is again a primary amine (RNH2).
- **Conclusion**: This option does not yield a secondary amine.

5. **Option C**:
- This involves the reaction of a primary amide (RCONH2) with an aldehyde (RCHO).
- The reaction leads to the elimination of water, forming an imine intermediate.
- When this imine undergoes hydrogenation (reduction) over platinum, it results in a secondary amine (R2NH).
- **Conclusion**: This option successfully yields a secondary amine.

6. **Option D**:
- This option involves a primary alkyl bromide (RBr) reacting with a nucleophile.
- The reaction leads to the formation of a primary amine (RNH2) rather than a secondary amine.
- **Conclusion**: This option does not yield a secondary amine.

7. **Final Conclusion**:
- The only option that leads to the formation of a secondary amine is **Option C**.

### Final Answer:
The set of conditions useful for preparing a secondary amine is found in **Option C**.

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