.. o: º· · ~ .. -------- ~~~ .·.'' '''•· ester b drol si inside tb body HN .. OH :oA O ltamivir ( old Tomiílu) O ltamivir carbo ylic cid Oselta mivir ( old a Tamiflu) is pre cribed for prevention and treatment of influenza . It is converted into oseltamivir carboxy lic acid by variou hydrolytic enzymes in the bloodstrearn. Oseltarnivir carboxylic acid i an active metabolite of Tamiflu, which i ultimately responsible for inhibiting the action of viral neuraminida e enzyme . Provide your re pon e for Boxes 1-4 based on o eltamivir carboxylic acid. Box 1: A ign the configuration to the alkene in oseltamivir carboxylic acid. Boxes 2 & 3: Specify the configuration of the chiral center marked with an asterisk (*) in oseltamivir carba ylic acid in Bo 2. List the Cahn-Ingold -Prelog priorities in Box 3 to show your work. Box 4: U e the benchmark pKa value to how the predominant ionization state of oseltamivir carboxylic in the blood tream (pH = 7 .2) in Box 4. Redraw the tructure of o eltarnivir carboxylic acid and do not forget to include the non-zero formal charges to indicate tbe ionized functional groups. 1 2 3 4 Problem 2: Boxes S & 6 (B points) OH o HO OH Y NHOH OH o - cetylneurnminic acid Glycoproteins decorated with N-acetylneuraminic acid derivatives are typicaJly found on tbe cell membrane and serve as receptors for influenza viruses. Tamiflu, with structural similarities to N-acetylneuraminic acid, was rationally designed to impede the entry of influenza viruses into rnammalian cells. Complete boxes 5 & 6 based on the structure of N-acetylneuraminic acid shown above. Box 5: How many chiral centers does N-acetylneuraminic acid possess? Box 6: Convert the line and wedge representation of N-acetylneuraminic acid into the corresponding chair representation. The C-1 substituent is already shown in the template provided in Box 6. Pay attention to the numbering and show the axial and equatoriaJ substituents in tbe correct orientation to get any credit for this problem. (Caution : Many students lost points on the previous quiz because they did not pay attention to the overall connectivity and the total numher of carbons.) Proltlem 2: (Boxes 5, 6) 5 6 OH OH Problem 3: Boxes 7, 8, 9 (26 points) . ,• , • ... .. .. ----··.· .··--· .._ .,a·•· o.. ~ ...., .. This probl em is based on the bases shown in t/ze above oval: Box 7: Draw the structures of bases indicated in the above oval in the order of INCREASING basicity. Start with the weakest base on the left and finish with the strongest base on the right. Box 8: Complete the equilibrium indícated in Box 8 by following the steps indicated below: Step 1: Among various bases indicated in the oval above, identify a suitable base that resu1ts in the overal1 Keq significantly greater than 1. Step 2: Comp lete the equilibrium by drawing the structures of conjugate acid and conjugate base on the right. These specie are NOT sbown in the above oval . Step 3: Show curved arrows to depict the flow of electrons among the reactants in the equilibrium you write. Box 9: Use your knowledgc of benchmark pKa values to calcuJate the equilibrium constant for the reaction you wrote in Box 8. Powers of 10 are acceptable AND you need to show your calculations explicitly. Problem 3: Boxes 7, 8, 9 7 8 + conjugare acid conjugat e base 9 Problem 4: Boxes 10 & 11 (10 points) e~ OH 3-cbJoro-3-mcthylbutanoiac id ( MB ) (pK ~ 4.0) Complete Boxes 10 & 11 by providing the tructure related to 3-chloro-3-methylbutanoic acid (abbreviated a 3C3MBA) that meet ali indicated criteria. Box 10: Provide the tructure of a constitutional i omer of 3C3MBA that po esses one chiral center and is expected to be 10 times moreiacidic than 3C3MBA itself (roughly one pKa unit below 4.0). Show the chiral center in R configuration . Box 11: Provid the tructure of a con titutional i omer of 3C3MBA that po sesses no chiral centers and i expected to be 10 times le acidic than 3C3MBA it elf (roughly one pKa unit above 4.0). Problem 4: Boxes 10, 11 10 11 Problem 5: Boxes 12, 13, 14, 15, 16 (18 points) .. o: H 0 \ N..- pcci Part I: Copy the tructure of pecie A in Box 12 and draw three additional valid re onance strucrures for the species (A) in Boxes 13-15. In lude the curved arrow to how the flow of electron from tructure Box 12 ~ 13 ~ 14 ~ 15 ~ 12. You mu t how all l · rmal charg§_to receive full credit on thi problem. di cu ed in lecture , following the ommand men for drawing re onance structure correctly i non-negotiable. AVOID STRUC TURE WITH CHARGE EPARATIO . Part Il : Box 16: Draw the resonance structure of Species A that contr ibutes the most to the overall resonance hybrid . Show all lone pairs and non-zero formal charges. Problem 5: Boxes 12 - 16 12 13 l l 15 14 16