Question

Identify the major product A and B in the following reaction sequence
CH3Br--Agcn(a/c)-A--liAlH4-B

Answer 1

Answer:

CH₃Br + AgCN ⇒ CH₃NC ⇒ CH₃NHCH₃ (N,N dimethyl amine)

                            (reduction)

Explanation:

Answer 2

CH3Br--Agcn(a/c)-CH₃NC--liAlH4-CH₃-NH-CH₃.

When alcoholic Silver cyanide (AgCN) reacts with CH₃Br, we get Methyl Isocyanide ( CH₃NC) as the main product.

This is because, the attack happens from N atom, and the resultant formed is NC⁻, isocyanide ion.

CH₃Br + AgCN → CH₃NC + AgBr.

Thus CH₃NC is A.

Reduction reaction occurs when CH₃NC reacts with LiAlH₄.

As, the N atom is already bonded with 2 C atoms, so only 1H atoms get associated with N (valency is 3). As in reduction, H atoms get attached.

Whereas the C atom is bonded with 3 atoms of H (valency is 4), and the other bond is with N.

CH₃NC + LiAlH₄ → CH₃-NH-CH₃

So, the reduced product formed is CH₃-NH-CH₃, this is B.