Show how you would convert glycine to following derivatives. Show the structure of the product in each case.

(a) Glycine isopropyl ester

(b) N-benzoylglycine

(c) N-benzyloxycarbonylglycine

(d) Tert-butyloxycarbonylglycine

Glycine when treated with propan-2-ol under acidic medium gets converted to glycine isopropyl ester. In acidic medium both the nitrogen of the amino group and the hydroxyl moiety present in the carboxylic acid gets protonated. The hydroxyl group gets converted to water which acts as a leaving group.In next step, hydroxyl group of propan-2-ol acts as a nucleophile and attacks at the carbonyl carbon of carboxylic acid group because of which required product is obtained.

Formation of the required derivative of glycine

Glycine when treated with benzoyl chloride in the presence of pyridine gets converted to N-benzoylglycine. Amino group of glycine is nucleophilic in nature and attacks at the carbonyl carbon of benzoyl chloride due to which a peptide bond is formed and chloride ion acts as a leaving group. Pyridine acts as a base and helps in the neutralization of the charge of the amino group after peptide bond formation.

Formation of the required derivative of glycine

Glycine when treated with benzyl carbonochloridate in the presence of base like triethylamine, gets converted to its derivative N-benzoyloxycarbonylglycine. Amino group of glycine is nucleophilic in nature and attacks at the carbonyl carbon of benzyl carbonochloridate due to which peptide bond is formed and chloride ion acts as a leaving group. Triethylamine acts as a base and helps in neutralisation of the charge of the amino group after peptide bond formation.

Formation of the required derivative of glycine

Glycine when treated with di-tert-butyl dicarbonate gets converted to tertiary butyl oxycarbonylglycine. Amino group acts as a nucleophile in glycine and attacks at the carbonyl carbon of di-tert-butyl dicarbonate and -OCOOCMe₃ eliminates as a leaving group due to which a peptide bond is formed and required product gets obtained.

Formation of the required derivative of glycine