User interface language: English | Español

Date November 2016 Marks available 2 Reference code 16N.3.hl.TZ0.26
Level HL Paper 3 Time zone TZ0
Command term Outline Question number 26 Adapted from N/A

Question

Excess stomach acid leads to medical conditions that affect many people worldwide. These conditions can be treated with several types of medical drugs.

Omeprazole exists as a racemic mixture whereas esomeprazole is a single enantiomer. Outline how, starting from a non-chiral molecule, esomeprazole but not omeprazole, could be synthesized. Details of chemicals and conditions are not required.

Markscheme

Any two of:

chiral molecule/auxiliary/optically active species is used/added/connected «to the starting molecule to force reaction to follow a certain path»

chiral intermediate forms «only» one enantiomer
OR
auxiliary creates stereochemical condition «necessary to follow a certain pathway» / stereochemical induction
OR
existing chiral centre affects configuration of new chiral centres

«after new chiral centre created» chiral auxiliary removed «to obtain desired product»

Examiners report

[N/A]

Syllabus sections

Options » D: Medicinal chemistry » D.7 Taxol—a chiral auxiliary case study (HL only)
Options » D: Medicinal chemistry
Options

View options