Question

1) What type of reaction occurs when aniline (PhNH₂ ) is added to benzaldehyde (PhCHO)? Draw the full mechanism for this formation of aldimine (proton transfers should be drawn using strongest base). I solved is (Z)-N,1-diphenylmethanimine

2) What is the by-product of Reaction A? Write the balanced reaction that would occur between this by-product and sodium borohydride.

3) What reaction could occur with Product A if it sits out on the benchtop that would cause it to revert back to starting materials? If sodium borohydride is added to these starting materials, which one would react to give a new product after neutralizing workup? What is the structure of this product?

4) Explain which compound in each pair is expected to a) be more polar and b) have a higher Rfbenzaldehyde vs. ortho-vanillin and aniline vs. para-toluidine

5) The same reaction A can be carried out with starting materials para-anisaldehyde and para-toluidine. Explain using the structural features of each compound the expected order of largest to smallest Rf on a TLC plate between para-toluidine, para-anisaldehyde, and their imine intermediate.

6) What is the problem if there are large, hard lumps and no remaining MgSO₄powder in B8?

Answer 1