Chemistry Questions and Answers May 05, 2020

a)i) Apply Lipinskis Rules to the structure of indinavir. a)ii) What does your Lipinski analysis tell you about the suitability of indinavir as a drug? Briefly explain the limitations of this analysis. b)i) Demonstrate your understanding of retrosynthetic analysis by redrawing step (iii) in the retrosynthetic direction. Show the disconnection,

N. OH OH Indinavir 1 Molecular Weight 613.80 logP 2.49 ZI

(a) In the first stage of step (i) a reaction between DMSO and oxalyl chloride takes place to generate the active intermediate 12. Provide a curly arrow mechanism to show how the reaction of 12 with alcohol 8 gives aldehyde 9. (Hint: remember triethylamine is also present in the reaction mixture.) (b) Demonstrate your understanding of

) DMSO, (COCI), EtN OTBS MOM H OTBS 8 osa 12 OH ) a) nBuli (2 equiv.) OTBS 10 b) H OTBS MOMO 11 TBS tertbutyldimethylsily MOM methoxymethyl DMSO dimethylsultoxide

(a) In a recent synthesis of the cyclic peptide 13, which has antibiotic activity, the authors chose the disconnection point illustrated in the retrosynthetic scheme below, to give two protected fragments 14 and 15. I. Suggest a reason why this might be considered a good point for a first disconnection. 1 mark II. Fragments 14 and 15 could be

HN H HN NH2 NH HN OH NH 13 NCN DCC, NEI, DCC HN OMOM NBoc NH2 HO 15 NH HN 14

(a) Imidazole is a much stronger base than pyrrole (the pKa's of the conjugate acids are 7.1 and -3.8, respectively). Explain why this order of basicity occurs and show the position of protonation. 6 Marks (b) The pyridine N-oxide, compound A, is a new drug claimed to be useful for the treatment of senile dementia. Industrial synthesis of it is

Z Z

(a) The companys chemical development group completed a three-step synthesis (outlined below) of compound E from which they proposed to make molecules of the type D. I. Outline a mechanism for Step II. Account for the selectivity seen in the electrophilic aromatic substitution reaction that has occurred in Step 3. Give a brief mechanistic

NHAlkyl N D Aryl

In Prof. Patersons synthesis, the thioester (1) was deprotonated to generate an enolate (2) with defined stereochemistry, which then participates in an aldol reaction with aldehyde (3) to give the product (4) (a) Suggest a structure for enolate (2) (b) Using cyclic deprotonation models, justify why the enolate (2) has a particular stereochemistry

ebelactone A OH

During Prof. K. C. Nicolaous synthesis of the oestradiol analogue, methylcyclopentanone (5) underwent a reaction cascade to give a stereodefined product (7). (a) Suggest a structure for the organometallic reagent. 2 marks (b) Suggest a structure for the intermediate (6). 1 mark (c) Using curly arrow notation, draw out the mechanism for the

H H HO oestradiol oestradiol analogue

A solution prepared by dissolving 682 mg of a sugar jar molecular compound and a nonelectrolyte) in 100g of water froze at-372C. What is the molar mass of this sugar? The value of K is 1.86C/m. 9mol

4. The Unknown Sample Solution will contain between 40 and 70 soluble Chloride lon in grams. Assuming a initial mass of 0.2 grams of unknown sample in solution and 0.2 M solution of Silver Nitrate precipitating agent, estimate the volume of Silver Nitrate solution that should be added to insure complete precipitation of the Chloride. MW AgCl

When 5.00 mol of benzene is vaporized at a constant pressure of 1.00 arm and at its normal boiling point of 80.1 degrees Celcius, 169.5 kJ are absorbed and P delta V for the vaporization process is equal to 14.5 kJ then....

A) AE 184.0kJ and AH 169.5 kJ. AE 169.5 kJ and AH 184.0 kJ. B) AE 155.0 kJ and AH 169.5 kJ. AE 1695 k and AH 155.0 kJ. 3 i

While performing absorbance measurements of standard solutions, Taranpreet used 8 mL of solution in the cuvette for each determination. She then repeated the same measurements using 6 mL of solution in the cuvette for each determination. For each set of measurements, she used the same spectrometer with the same cuvette, and assume that for each

A weak acid A with K, 1.82 x 10 has a partition coefficient K between water and an organic solvent of 2.5. A weak base B with a K 3.45 x 10 has a K of 1.2 with the same organic solvent is mixed with A. Is it possible to obtain an extract that is 90 pure, or greater, in either A or B Explain. 3D

50 ml of an aqueous solution of 0.1 moL toluene was extracted into 10 mL of octanol. If Log K is 3.6, calculate the concentration of toluene left in the aqueous phase.

A 100 mL solution contains 0.0010 molL of calcium chloride and 0.0010 molL of strontium chloride. 50 ml of 0.1000 molL sodium sulfate is added. Determine the percentage by mass of calcium sulfate in the product. The solubility products value of calcium sulfate is 9.1 x 10 and for strontium sulfate it is 3.2 x 107. 6 marks 50 mL of an aqueous

1. In an electrolytic cell, reduction occurs at the _____ and oxidation occurs at the _____.

3.If an electric current is passed through a solution of molten potassium bromide, KBr, the product at the cathode is _____. Answer: 4. When a secondary battery provides electrical energy, it is acting as a voltaic cell. When the battery is recharging, it is operating as a(n) _____ cell.

4. When a secondary battery provides electrical energy, it is acting as a voltaic cell. When the battery is recharging, it is operating as a(n) _____ cell. Answer: 6. Calculate the copper(II) ion concentration at 25 C in the cell Zn(s) | Zn2+(aq, 1.0 M) || Cu2+(aq) | Cu(s) if the measured cell potential is 1.06 V. The standard cell potential is

7. Use the following standard reduction potentials to determine which species is the strongest reducing agent. 2 H+(aq) + 2 e H2(g); 0.00 V K+(aq) + e K(s); 2.93 V F2(g) + 2 e 2 F(aq); 2.87 V Al3+(aq) + 3 e Al(s); 1.66 V Pb2+(aq) + 2 e Pb(s); 0.13 V Answer: 8. Write a balanced net ionic equation for the overall reaction represented by the

10. Give any three uses of lime. Answer:

11. What is the chemical formula for quick lime and slaked lime? Answer: 12. When the given oxidationreduction reaction in an acidic solution is balanced, what is the lowest whole-number coefficient for H+, and on which side of the balanced equation should it appear? MnO4(aq) + Br(aq) Mn2+(aq) + Br2(l)

13. Which of the following statements is/are CORRECT? 1.For a chemical system, if the reaction quotient (Q) is greater than K, reactant must be converted to products to reach equilibrium. 2.For a chemical system at equilibrium, the forward and reverse rates of reaction are equal. 3.For a chemical system at equilibrium, the concentrations of

15. What is the relationship between Kp and Kc for the reaction below? N2(g) + 3 H2(g) 2 NH3(g) a. b. c. d. e. Answer: _____ 16. Given the following chemical equilibrium, COCl2(g) CO(g) + Cl2(g) calculate the value of Kc, given that Kp = 6.5 x 1011 at 298 K. (R = 0.08206 L.atm/mol.K) a. 1.5 x 1012 b. 3.8 x 1011 c. 1.1 x 109 d. 2.7 x 1010 e. 1.6 x

At a high temperature, equal concentrations of 0.160 mol/L of H2(g) and I2(g) are initially present in a flask. The H2 and I2 react according to the balanced equation below. H2(g) + I2(g) 2 HI(g) When equilibrium is reached, the concentration of H2(g) has decreased to 0.036 mol/L. What is the equilibrium constant, Kc, for the reaction? 18. At 25

19. Given the following chemical equilibria, N2(g) + O2(g) 2 NO(g)K1 N2(g) + 3 H2(g) 2NH3(g)K2 H2(g) + O2(g) H2O(g)K3 Determine the method used to calculate the equilibrium constant for the reaction below. 4 NH3(g) + 5 O2(g) 4NO(g)+6 H2O(g) K c Answer: _____ 20. Assume that the following endothermic chemical reaction is at equilibrium. C(s) +

Thiamine 1 is an essential component of the human diet; in is absence, the human vitamin deficiency known as beriberi develops. i. List the requirements for aromaticity. ii. Show that each ring of thiamine 1 fulfills the requirements for aromaticity. iii. If the acetamide (H2N-CNH-CH3), in Step 1 was replaced by urea (H2N-CO-NH2), what would the

c NH2 CH3 H3C CH2CH2OH 1

21. What is the conjugate base of [Fe(H2O)6]3+(aq)? a. H3O+ b. [Fe(H2O)6]2+ c. [Fe(H2O)5H3O]4+ d. [Fe(H2O)5OH]2+ e. [Fe(H2O)5]3+ Answer: _____ 22. Which is NOT an amphiprotic species in water? a. HClO3 b. HSO3 c. H3O+ d. HS e. HCO3

23. A solution is prepared by diluting 0.055 mol HNO3 with water to a volume of 1.75 L. What is the pH of the solution? Answer: 24. An aqueous solution with a pH of 2.00 is diluted from 1.0 L to 3.0 L. What is the pH of the diluted solution? a. 0.67 b. 2.00 c. 2.48 d. 4.33 e. 6.00

25. At 25 C, all of the following ionic compounds produce a basic aqueous solution, except ____. a. NaF b. Na3PO4 c. NaNO2 d. NaHSO4 e. NaCH3CO2 Answer: _____ 26. What is the equilibrium constant for the following reaction, HCO2H(aq) + CN(aq) HCO2(aq) + HCN(aq) and does the reaction favor the formation of reactants or products? The acid

27. Given the following acid dissociation constants, Ka (H3PO4) = 7.5 x 103 Ka (NH4+) = 5.6 x 1010 determine the equilibrium constant for the reaction below at 25 C. H3PO4(aq) + NH3(aq) NH4+(aq) + H2PO4-(aq) a. 4.2 x 1012 b. 7.5 x 108 c. 4.2 x 102 d. 1.3 x 107 e. 2.4 x 1011 Answer: _____ 30. When a Lewis acid combines with a Lewis base, the base

29. The chemical equations below show the reaction of Al(OH)3 as a Lewis acid and as a Lewis base, respectively. Al(OH)3(s) + OH(aq) Al(OH)4(aq) Al(OH)3(s) + 3 H3O+(aq) Al3+(aq) + 3 H2O( ) Substances that can behave as either Lewis acids or bases are called ________ substances. Answer: 30. The following reaction occurs spontaneously. 2 H+(aq) +

31. All of the following statements concerning voltaic cells are true EXCEPT a. a salt bridge allows cations and anions to move between the half-cells. b. electrons flow from the cathode to the anode in the external circuit. c. oxidation occurs at the anode. d. a voltaic cell can be used as a source of energy. e. a voltaic cell consists of

a. Lamivudine 1 is an inhibitor of HIV reverse transcriptase and is used to combat HIV. i. Apply Lipinskis Rules to the structure of lamivudine. ii. What does your Lipinski analysis tell you about the suitability of lamivudine as a drug? What are the limitations of this analysis? iii. By comparing the structure of lamivudine 1 to cytosine

NH2 NH2 N. HO HO S HO Lamivudine 1 Cytosine deoxyribonucleotide 2 Molecular Weight 229.25 LogP 1.4

i. Demonstrate your understanding of retrosynthetic analysis by redrawing step (i) in the retrosynthetic direction. Show the disconnection, retrosynthetic arrow, and synthons corresponding to the starting materials. 2 marks ii. Now redraw step (iii) in the retrosynthetic direction, showing disconnections and synthons corresponding to the starting

OEt SH Br i. KOtBu OEt ii. NaOH OEt Ph HS Et DMF THF H20 Et Et 3 4 6 benzothioic Sacid iii. TSOH Ph. PhMe, 120 C OEt Lamivudine 1 Ph S 7 OtBu tertbutoxide (OC(CH3)3) Et ethyl (CH2CH3) DMF dimethylformamide Ph phenyl (CeHs) TSOH ptoluenesulfonic acid THF tetrahydrofuran PhMe toluene

Genome mining is an emerging approach to drug discovery. i. Genome mining involves a combination of genomics, bioinformatics, molecular biology, and analytical chemistry. Briefly outline what takes place at each of these steps in the process. ii. What are the general features of a pleiotropic approach to activating a silent biosynthetic gene

Consider these steps from the recent literature and answer the questions that follow. i. Briefly explain what is happening at each step (i)(iv). 2 marks ii. By considering the acetate (CH3CO), tert-butyldimethylsilyl (TBDMS) and benzyl (Bn or PhCH2) groups used in this example, explain what is meant by an orthogonal protecting group strategy. 2

i. TBDMSCI, Et,N HO . COTBDMS ii. KCO3, CHOH 8 iii. BNCI, Et,N iv. TBAF v. DMSO, (COCI)2, EtN TBDMS tertbutyldimethylsilyl TBAF tetranbutylammonium fluoride BnCI CI DMSO dimethylsulfoxide 10 H

Consider these steps the recent literature and answer the questions that follow. i. Propose a mechanism for step (i), formation of the thioacetal 12. 3 marks ii. Propose a mechanism for step (ii). (Note that n-BuLi is a strong base, and assume that the alkoxide intermediate is protonated upon workup.) 2 marks iii. Draw the synthon corresponding to

HO, R i. HS R SH H H R ii. nBuLi HCK9) then o H 11 12 R OBn 13 Bn OBn Bn O..

Consider liquid water at 1 atm. At 25C, the density of water is 0.997044 g cm 3 . The coefficient of thermal expansion, , is well fitted by = e + ft + gt 2 where t is in celsius and e = 1.00871 10 -5 K 1 , f = 1.20561 10 -5 C 1 K 1 , and g = 5.4150 10 -8 C 2 K 1 . What is the density of the water at 38C

The Shapiro Reaction involves the base-mediated decomposition of sulfonyl hydrazones like 14 below. Methyl lithium (CH3Li) is a strong base; Ar = p-tolyl (i.e. para-methylphenyl, -C6H4CH3). i. Under conditions A, doubly-deuterated product 15 is formed. Draw a mechanism to explain this outcome. 3 marks ii. Under conditions B, the mono-methylated

Os.Ar N. N D A i. 2x CHLI, 78 C. ii. D20 Ph. D 15 O Ar Ar N. NH i. 2 x CH3LI, 78 C ii. 1x CH3I iii. H20 (workup) Ph. N Ph. 14 16 D i. 2x CHLI, 25 C ii. D20 Ph. 17 z

i. Consider the following ring systems 1-4. List the properties that are needed for a molecule to be aromatic. Comment briefly about each and indicate clearly (with reasons) whether or not it should be aromatic? 4 marks ii. 4-Amino-N-(5-methylisoxazol-3-yl)-benzenesulfonamide) is an antibiotic with the trade name sulfamethoxazole. It was recently

N. CIO, 1 4 IZ 2.

Rationalise the following observations using valence-bond structures for the possible intermediates. Pyridine undergoes electrophilic substitution only with difficulty and predominantly in the 3-position, while pyridine N-oxide undergoes electrophilic substitution very easily and predominantly at the 2- and 4-positions. (8 marks)

E difficult E E easy NF E

Give the constitutional formula of the major product of each of the following reactions. Give a brief mechanistic justification of your answer in each case. (8 marks) i. ii. iii. iv.

1. NaNH2 C3H9N CH2CH3 2. CH31

a. There are three diazines (C4H4N2) differing in the relative arrangements of the two nitrogens in the six-membered ring. i. Why is it difficult to diprotonate a diazine? 1 mark ii. Which is the only chlorodiazine that does not undergo easy nucleophilic substitution of the chloro group, and why? 2 mark iii. The 1,3-diazine derivative,

.N. NN pyridazine pyrimidine pyrazine

i. Suggest a structure for product B. ii. Draw a plausible mechanism for the conversion of the Pd(II) reagent PdCl2(PPh3)2 into the catalytically active Pd(0) species. 6 marks iii. The vinyl stannane used in this cross-coupling is extremely toxic. Suggest another organometallic reagent that could be used instead of the stannane. 1 mark

SnBuz Br PdCl2(PPH32 product (B) dioxane, A 91 (A)

i. When ketone C is reacted with LDA a single enolate isomer is formed. Using 3D representations, rationalize which enolate isomer (E or Z) is formed. 8 marks

OH recall that LDA i. LDA N. N. N ii. Li Bn Bn (C) H. (D)

i. Illustrate your knowledge of metathesis processes by drawing the mechanism for the cross-metathesis reaction of compounds E and F. Ensure that you use appropriate curly arrow notation

Grubbs(Il) cat. Grubbs(II) cat. OMe OMe mesNNmes (E) CRUE Ph OMe OMe O,Me (G) O,Me (F)

i. Demonstrate your understanding of aldol chemistry by drawing Zimmer-Traxler structures to account for the syn stereochemical relationship between the new stereogenic centres in compound J marked 1 and 2. 9 marks n

OLi OH TBSO OBn TBSO OBn (H) (1) (J) 2.

i. The reduction of ketone K with sodium triacetoxyborohydride yields the anticonfigured alcohol L. Using your knowledge of Felkin-Anh control, rationalize this stereochemical outcome. 9 marks

OH OTBS OBn OTBS Na HB(OAc)3 OBn R R (K) (L)

Briefly describe your understanding of the role/functions of each element of the AIS model that follows. Provide an example where applicable: (i) Data Sources (ii) Data collection (iii) Data processing (iv) Information Generation (v) Feedback

Consider the H, molecule with atoms HA and Hg separated by a distance R HAHa. The probability density for the 0y and o 1,orbitals of H, are given below ois Node 015 42 42 HA HA H. Within the LCAO approximation, the wavefunction of the 01, orbital of H, can be written as (18A 1sB) with an energy of E, HAAHAR 14SAB V225 AB The wavefunction of the

Draw an organic-rich wastewater contaminant plume propagating from a cesspool and within the plume draw a possible sequence of redox zonation, indicate solutes and microbial processes of importance you expect to see in each zone. Discuss the role of autotrophic and heterotrophic microbially mediated reactions that are associated with the redox

For the following hypothetical reaction, A B2AB, the reciprocal of the plot of A (in moles per 22.4 L) versus time has a slope of 5 when both A and B are at unit concentrations. Determine the rate constant for the disappearance of B2 in units of mmols and ms.

For the protein sequence given below which is known as an alpha-helix: 1)Ile-Arg-Lys-Leu-Ala-Asp-Ile-Leu-Thr-Arg-Leu-Trp-Lys-Val How can you calculate the maximum possible number of turns of this a-helix? (you should explain your way of thinking) 2) Examine and think carefully about the protein sequence given below which is known as an a-helix:

Given the following minerals which one(s) would you choose as a possible material for a first order compensator, please explain why for each material even if the material is not a good fit you must explain why its not a good fit. Agat, Obsidian, Beryl, plagioclase, garnet, anatase, apatite, perovskite

Consider this reaction 2N,0, (g) 2N,04 (g) 02 (g) At a certain temperature it obeys this rate law. rate (0.0117 s)N,05 S Suppose a vessel contains N,0, at a concentration of 0.270 M. Calculate the concentration of N,0, in the vessel 56.0 seconds later. You may assume no 5. other reaction is important. Round your answer to 2 significant digits.

if you burn 40 g of oil and produce 30 g of carbon dioxide, what is the total mass of all the products produced from the buming of this O 30 g O less than 40g O More than 40 g O 40 g

Dipole moment, (Hexane,Cyclohexane,Toluene) and refractive index, The data are as follows Flask 1 2 3 20 18 1.89 2.015 18.5 0.9484 2.379 The factor (27, KTL) has the value 1.633x1054 cm 1. V1 108.1X106 (mmol) 16 14 DMR 12 10 8 6 DMR measurement of three solvents were obtained along with their dipole moment reading 1.8 DMR RI Hexane 7.25 3.7400

In this experiment, the mass of pure copper provided is 0.491 gram, and then it was dissolved in nitric acid. An ammonia solution was added into it and transferred to a 100mL volumetric flask and dilute to 100ml with distilled water. This is the original standard solution. Then a diluted solution was prepared by adding 11 mL original standard

Predict the product of the following reaction HC (1 equiv.) No reaction

name for the following compound ,Enter the correct name of the following compound

I) Calculate the milliliters of NaOH solution, and the grams of NaCl, necessary to create 50.00 mL of a pH 5.00 buffer at an ionic strength of 0.1000. Use Activities, alpha(Ac), the charge balance equation, and the ionic strength equation. II) Calculate the milliliters of NaOH solution necessary to create 50.00 mL of a pH 5.00 buffer. Use the

A water sample from which 10, 1, and 0.1 ml/100mL dilutions resulted in 5, 4 and 3 positive lactose-fermentation tubes, respectively. Determine the MPN/100 mL through finding the maximum value of y*a. .

What is the appropriate [H+] of a solution with a measured pH of 5.31? Give your answer to two significant figures. Do not include the unit label M in your answer.

100.0 ml of solution that is o.700 M in chloride anion, Cl, using magnesium chloride. Eneter the calculated mass of MgCl, needed. Enter the concentrations of ions as seen in the information panel of the virtual lab. Mg CI IN

10)Examine each of the errors below, discuss how the error would affect the separation. Describe how each error would impact the efficacy of the purification (better separation, worse separation, no effect). (Error) a) Overbunched cotton ball at bottom of column b) The silica gel is not level when the sample is loaded onto the column c) Half as

Which of the following cell reactions would require the use of an inert conducting electrode Ba(s) 2Ag(aq) 2Ag(s) Ba2(aq) O Co(s) 2MNO2(s) 2NH4 (aq) Co(aq) Mn203(s) 2NH3(aq) H20) 3Li (aq) Al(s) 3Li(s) Al (aq) O 3Ba(s) 2AU3(aq) 3Ba2 2Au(s) Cuts) 2Ag(aq) Cu2(aq) 2Ag(s)

If you were to prepare a concentrated buffer and a diluted buffer both at the same pH and then add HCI to each one, what should happen O The pH of both solutions will increase, with the pH of the diluted buffer increasing most. O The pH of both solutions will decrease, with the pH of the diluted buffer decreasing most. O The pH of both solutions

1. A 1.00 L Tris buffer solution is made by mixing 121.14 g of Tris base (MW = 121.14 g/mol), 84 mL of 10 M HCl and 916 mL of water. What is the pH of the prepared Tris buffer? 2. A lab mate accidentally spilled 10 mL of 10 M HCl onto the petri dish culturing Azotobacter. How much do you expect the pH of the solution to change (little, a lot or

Compound 8 cannot be prepared by the bromination of the parent thiazole ring system. By consideration of the intermediates involved rationalize why the 5- position is the site of the first bromination.

heat .CI H2N NH2 with aq. HCI Br, excess POBr3 98 yield Br 85 yield 8

Compound A has a larger enthalpy (heat) of condensation than compound B. Which of the following statements is true i. Heat will be released during the condensation of both substances. ii. Compound A will have a lower normal boiling point than compound B. ii. CompoundA will have a lower vapour pressure at 25C than compound B. All three statements

What are the similarities and differences in the biosynthesis of glycosphingolipids, GPI anchors, and N-linked glycans?

Suppose one were able to prepare a onedimensional chain of Be with a long interatomic spacing of, say, 2.5 . Lets take, a 10 eV, a 5 eV, B 0.8 eV, B 1.4 eV. 2 P P S a, 10 eV, ap 5 eV, P, 0.8 eV, P 1.4 eV. Draw the band structure (the dispersion curves and the DOS). If the scattering time for all the carriers in the system at 298 K is 2.0

The PT phase diagram of a certain substance shows a positive solidliquid slope. What will happen when pressure is increased on an equilibrium mixture of the solid and liquid O Liquid will solidify O Solid will melt liquid will vaporize O Nothing, since the system is at equilibrium

Select 14) Which category for organic reactions is shown in the equation below ELOH, ELONA Br heat A) Addition B) Substitution C) Elimination Rearrangement Select 15) Which category for organic reactions is shown in the equation below Br A) Addition B) Substitution C) Elimination D) Rearrangement

(2) EntKaurene is an important (diterpene) biosynthetic intermediate in making many bio active agents, including plant hormones such as gibberellins. Indicate the isoprene units in entkaurene. Note the biosynthetic pathway for this diterpene shown starting from geranylgeranyl pyrophosphate (GGPP) shown below1 I expect you to identify the correct

Reagents to accomplish the following transformation are (a) 1. (Sia) BH H20, HO 2. Na Cr0, H3O 3. NH, heat 4. POCI, (c) (Sia) BH H2O, HO 2. HCN, KCN (b) (Sia) BH H,O, HO 2. NABH, CH,OH 3. PBr, 4. NaCN, DMSO (d) 1. (Sia) BH H,O2 HO 2. Na,Cr,O, HO 3. NH, heat 4. LIAIH HO O a Oc

(a) A synthesis of pyrimidine is outlined below (i) Give a mechanism for Step 1. (5 marks) (ii) Give a mechanism for Step 2. (2 marks) (b) Give the structure of the product formed in the following reaction. (2 marks) (c) Uracil can be converted into cytosine by the following reaction sequence: i) Provide a reaction mechanism for Step 3. (2 marks)

cat. HCI N. H H. H2N NH2 in EtOH, heat Step 1 POCI3 heat Step 2 N. H2PdC N. in EtOH N CI Step 3 ZI

In Prof. Tokuyamas synthesis, the oxazolinone (A) was deprotonated to generate an enolate (B) with defined stereochemistry, which then participated in an aldol reaction with the chiral aldehyde (C) to give the product (D). (a) Suggest a structure for enolate (B) (2 marks) (b) Using cyclic deprotonation models, justify why the enolate (B) has a

i. LDA N enolate (B) (A) ii. Li 4 recall that LDA H3 (C) iii. HH20 OH OH NaOMe MeO 1 4 3 (E) (D)

4. We consider a DHKE protocol over a Galois fields GF(2m). Up to now, we have been using groups but it is possible (and simple) to use GF for DHKE. Here, the generator is a polynomial (denoted as g(x)) and we have an irreducible polynomial instead of our public prime p (denoted as p(x)). (a) In our example here, all arithmetic is done in GF(25)

Consider a methane molecule and assume the rigid rotor approximation. Quantify the signed error (incorrect minus correct answer) in its rotational entropy if the point group of the molecule was incorrectly assigned as C1 instead of Td. Provide your answer in units of J/K.mol and to two decimal places

14. a) An unknown compound has a mass spectrum showing an M peak at 137, with an (M1) peak that has a relative intensity of 11.1. There is no observed (M1) peak. What is the molecular formula of the unknown compound and what is the Hydrogen Deficiency Index (HDI) Molecular formula HDI

A reaction had initial concentrations of Fe3 and SCN equal to 0.0020 M and 0.00050 M respectively. After mixing the solution and measuring the absorbance, the concentration of FESCN2 was found to be 6.2 x 105 M. Set up the ICE table for this reaction AND calculate the value of Kc. Kc

The detection limit or Cm is defined as the smallest quantity of analyte that is significantly different from the blank. A calibration curve was collected for A 0.845xZn, ppm). The average and standard deviation of the blank was calculated to be 0.027 and 0.002, respectively. What is the concentration detection limit Cm in ppm Report your answer

1. a) Describe the intermolecular and intramolecular forces for Chlorpromazine. (please list all of them with detail) b) Connect and discuss how the molecular structure and forces relate to its physical/chemical properties. Please show detail. Thank you

A S0.0 mt ample wt 0,04 M CCHycoOR ie tiuated with a.040 M aol. hat the pf of the eolution after 30.0 nt of NaoH have beei added to the atid IK1.3 10 4.94 4.02 3.95

Would alpha-D-glucopyranose and alpha-D-fructopyranose be equally likely to be the substrate for a given enzyme? Refer to both shape and noncovalent interactions in your answer. Make one generalization about protein-carbohydrate interactions

1. a. On average, people use one tea bag (2.5 g of tea) to make an 8 ounces glass of iced tea. The 8 ounces glass of iced tea contains 10 mg of caffeine per ounce of iced tea. Given this information and the data above the % recovery in this experiment is? b. Is the % recovery a good yield? If not, suggest reasons why your experimental results were

The reaction below proceeds with a direct attack by a water molecule on the substrate, but the hydrolysis could be expected to proceed through two possible mechanisms. Draw two possible mechanisms for the reaction run in H182OH218O. Trace the progress of the 180180 label throughout each mechanism to see where it ends up this should indicate to you

Fill in blanks with the reagents or intermediate in the following road map. A B HO Br Br HNO3 H2S04 Zn HCI E Eto NO2

What would be the order from fastest to slowest if dichloromethane added to these compounds reacted with a bromine solution ?: toluene, ethylbenzene, isopropylbenzene, t-butylbenzene, cyclohexene, and cyclohexane. Note: No catalysts were used and light was only used for two of the compounds above to get a reaction.

5) Provide the initiation, propagation and 3 termination steps for the reaction. You dont have to show the radical initiator in your mechanism and you can start from bromine instead of NBS for the initiation step. Ph Ph NBr (benzoyl peroxide) (Br2) a) Initiation step(s) b) Propagation step(s) c) termination steps

An analytical chemist is titrating 117.3 ml of a 0.2700 M solution of butanoic acid (HC,H,CO,) with a 1.200 M solution of KOH, ThepK, of butanoic acid is 4.82. Calculate the pH of the acid solution after the chemist has added 14.63 mL of the KOH solution to it. Note for advanced students you may assume the final volume equals the initial volume of

Set up and solve the secular determinants for (a) hexatriene, (b) the cyclopentadienyl radical in the Hckel p-electron scheme; find the energy levels and molecular orbitals, and estimate the delocalization energy.

Draw a schematic pathway, specifically naming components and state (in a few sentences) how membrane bound Phosphatidylinsoitol (PI) leads to the regulation of protein function by the phosphorylation.

(a) Suggest a structure for enolate (B) (b) Using cyclic deprotonation models, justify why the enolate (B) has a particular stereochemistry (E or Z). (8 marks) (c) Using Newman projects, account for why compound (D) has the syn stereochemical relationship between the stereogenic centres labelled 3 and 4. (8 marks) (d) When the auxiliary is

i. LDA N enolate (B) (A) ii. Li 4 recall that LDA H3 (C) iii. HH20 OH OH NaOMe MeO 1 4 3 (E) (D)