Skip to content
dronacharya.ai
← JEE Advanced 2024 · Paper 1
ChemistrySingle correct+3 / -1Question 37 of 51

JEE Advanced 2024 · Paper 1, Chemistry question 3

Aspartame, an artificial sweetener, is a dipeptide aspartyl phenylalanine methyl ester. The structure of aspartame is

(Structures of phenylalanine and aspartic acid are given below.)

Phenylalanine: H₂N-CH(CH₂Ph)-COOH, drawn with the CH₂Ph group on a wedge (L-configuration).Aspartic acid: H₂N-CH(CH₂COOH)-COOH, drawn with the CH₂COOH side chain on a wedge (L-configuration).
Choose one option
Answer and worked solution

Official answer: B

Aspartame is L-aspartyl-L-phenylalanine methyl ester:

  • the α-carboxyl of aspartic acid forms the amide with the amino group of phenylalanine;
  • phenylalanine's carboxyl is the methyl ester;
  • aspartic acid keeps its free NHX2\ce{NH2} and its side-chain CHX2COOH\ce{CH2COOH}.

Only option (B) matches. (A) uses the side-chain carboxyl, (C) reverses the residues, and (D) esterifies the wrong carboxyl.

Topics:Amino acids and proteinsOptical isomerism and chirality
← Previous questionNext question →