Question

What alkyl halide is used in the acetamidomalonic ester synthesis to prepare a. lysine? b. phenylalanine?

Short answer

Formation of phenylalanine

Step-by-step solution

Ester synthesis

$\alpha$-Bromomalonic ester and potassium phthalimide undergo an SN₂ reaction. A proton is easily removed from the a-carbon of N-phthalimidomalonic ester because it is flanked by two carbonyl groups. The resulting carbanion undergoes an SN₂reaction with an alkyl halide.

Preparation of given amino acid

a)

4-Bromo-1-butanamine is used in the acetamido malonic ester syntheses to prepare lysine which is given as follows:

b)

Benzyl bromide is used in the acetamido malonic ester synthesis to prepare phenylalanine which is represented as follows:

Formation of phenylalanine (b)