(i) What is the drug target of Relenza (structure see below)? (5) (ii) Give the structure ((including stereochemistry) of the transition state (TS) that the drug is trying to mimic. (iii) Relenza is a close mimic to this TS apart from the guanidinyl group. What is the rationale behind the introduction of the guanidinyl group in the drug? (10) (iv) Tamiflu was developed from Relenza. Give the structure of Tamiflu and explain the rationale behind the structural changes made as compared to Relenza. (15) (v) Discuss why it is not possible to develop a glycoconjugate vaccine against viruses. (10) OH OH ACHN COOH HN. NH NH Zanamivir (Relenza)