Can I please have help with practical assignment 3 question 2. I need clear explanations and mechanisms related to this question. Everything should be in order including names of regeants used, solven

Page 1 of 6 CEM3B20 PRACTICAL ASSIGNMENT 1: ENOLATE ALKYLATION & ROBINSON ANNULATION DUE DATE : SATURDAY AUGUST 29, AT 12 :00 MIDNIGHT In this assignment, you are given the two -step synthesis of 1 0a-Methyl -1,9,10,10 a-tetrahydro -2H- phenanthren -3-one . This compound can be converted to a multitude of products in target -oriented synthesis. In STEP 1 , 3,4 -Dihydro -2H-naphthalen -1-one , known by its common/trivial name 1- tetralone, is alkylated with m ethyl iodide, using sodium ethoxide as the base. In STEP 2 , the alkylated 1-tetralone undergoes Robinson annulation with methyl vinyl ketone to give the desired 1 0a-Methyl - 1,9,10,10 a-tetrahydro -2H-phenanthren -3-one . PLEASE ANSWER THE FOLLOWING QUESTIONS 1. Look up the Material Safety Data Sheets (MSDS) of 1 -tetralone, methyl iodide and methyl vinyl ketone and summarize each in one paragraph . How many sections does a MSDS contain in general ? [15 ] 2. Sodium ethoxide can be bought as a solid , or as a solution in ethanol. It is prepared by reacting sodium metal with ethanol. If you were to do this in the laboratory yourself, how would yo u go about it? Please state the S afety Precautions that you would have to take in to account in doing so. [5] 3. Give a detailed reaction mechanism that explains formation of the product in STEP 2 . [5] 4. Laboratory experiments cost money and require careful financial planning . The costs include water and electricity, and waste disposal and thus very little waste should be generated in each experiment/process. For you as a student you just pay a nominal amount as tuition and get everything given to you. Companies do not have this privilege and invest a lot of money in scientific research , development a nd production, with the costs (plus profit) eventually borne by the consumer (patients in the case of pharmaceuticals ). Do the following Accounting Exercise to see how much it would cost to produce 2.00 grams of 10a - methyl -1,9,10,10a -tetrahydro -2H -phenanth ren -3-one , and compare that to the fe e you paid for tuition in this M odule. A ssum e 100% y ield for each step. Log into the Sigma Aldrich/Merck website O NaOEt, CH3I EtOH, 50 oC O 1-Tetralone NaOH EtOH-H2O, 50 oC O O STEP 1 STEP 2 10a-Methyl-1,9,10,10a-tetrahydro- 2H-phenanthren-3-one 1 9 3 8 4a 4b 5 10 10a 8a Page 2 of 6 to get current prices - please select the Country South Africa to get prices in Rands . You require a total of 150 ml of absolute ethanol : 100 ml in STEP 1 , and 50 ml (which you mix with 50 ml distilled water) in STEP 2 . [14 ] STEP 1 1-TETRALONE MINIMUM QUANTITY/PACKAGE required FROM MERCK GRADE/PURITY AND SIGMA -ALDRICH ITEM CODE Quantity required for the experiment Cost per gram METHYL IODIDE MINIMUM QUANTITY/PACKAGE required FROM MERCK GRADE/PURITY AND SIGMA -ALDRICH ITEM CODE Quantity required for the experiment Cost per gram SODIUM ETHOXIDE (Solid) MINIMUM QUANTITY/PACKAGE required FROM MERCK GRADE/PURITY AND SIGMA -ALDRICH ITEM CODE Quantity required for the experiment Cost per gram ABSOLUTE ETHANOL MINIMUM QUANTITY/PACKAGE required FROM MERCK GRADE/PURITY AND SIGMA -ALDRICH ITEM CODE Quantity required for the experiment 100 ml Cost per ml STEP 2 METHYL VINYL KETONE MINIMUM QUANTITY/PACKAGE required FROM MERCK GRADE/PURITY AND SIGMA -ALDRICH ITEM CODE Quantity required for the experiment Cost per ml SODIUM HYDROXIDE MINIMUM QUANTITY/PACKAGE required FROM MERCK GRADE/PURITY AND SIGMA -ALDRICH ITEM CODE Quantity required for the experiment Cost per gram ABSOLUTE ETHANOL MINIMUM QUANTITY/PACKAGE required FROM MERCK GRADE/PURITY AND SIGMA -ALDRICH ITEM CODE Quantity required for the experiment 50 ml Cost per ml TOTAL COST OF 2.00 GRAMS OF 10 a-Methyl -1,9,10,10 a-tetrahydro -2H- phenanthren -3-one. R…………………… Your 2020 Tuition Fee for this Module R…………………… Page 3 of 6 5. The following are the simulated 1H- and 13C-NMR spectral data of 10 a-Methyl -1,9,10,10 a- tetrahydro -2H-phenanthren -3-one. Please assign each signal to the appropriate Proton(s) and Carbon, using the same numbering scheme as given in the structure of the product. 1H-NMR (CDCl 3) δ/ppm : 1.26 (singlet, 3H); 1.36 (triplet, 2H); 1.58 (triplet, 2H); 2.55 (triplet, 2H) ; 2.94 (triplet, 2H) ; 6.22 (si nglet, 1H), 7.0 3 (triplet of doublets, 1H); 7.07 (doublet of doublets, 1H); 7.09 (triplet of doublets, 1H); 7.25 (doublet of doublets, 1H). Give the expected coupling constant ( J) values for each signal/peak. [10 ] 13C-NMR (CDCl 3) δ/ppm : 21.5; 27.2; 29.9; 38.4; 38.6; 42.4; 111.8; 125.6; 126.0; 127.5; 128.2; 134,7; 137.1; 166.5; and 197.6. [8] Look up the NMR Techniques called DEPT and in not more than 1 paragraph, explain how you would use these to accurately assign each 13C-NMR peak. [8] TOTAL: 65 MARKS Page 4 of 6 CEM3B20 PRACTICAL ASSIGNMENT 2: CONDENSATION REACTIONS IN NAPHTHALENE SYNTHESIS DUE DATE : SATURDAY SEPTEMBER 1 9, AT 12 :00 MIDNIGHT There are several methods of making naphthalenes, one of which is given in the experimental procedure below. Please read it carefully and answer the questions that follow. Step (a): To a solution of 2,4 -dimethoxybenzaldehyde ( (5.45 g , 32.80 mmol) and diethyl succinate (8. I 8 cm 3, 8.57 g, 49.20 mmol) in dry t -butyl alcohol (80 cm 3) stirred under nitrogen, was added potassium -t-butoxide (5.52 g, 49.19 mmol). The mixture was heated under reflux for 2 hours then allowed to cool to room temperature, poured into a separatory funnel containing ice and acid ified to pH 3 with cone. HCl (aq.). The product thus precipitate d was extracted into EtOAc (2x 100 crn 3), the combined extracts dried with magnesium sulfate, filtered through Celite and the filtrate concentrated on a rota ry evaporator. The resultant oi I was purified by column chromatography (10% EtOAc -hexane) to give the desired intermediate that was not characterized but immediately carried through step (b) below. Step (b): To the Stobbe co ndensation product from step (a) above, dissolved in acetic anhydride (100 cm 3), was added anhydrous sodium acetate (6.72 g, 81.91 mmol) and the mixture heated at 140 °C under argon for 2 hours then allowed to cool. Acetic anhydride was removed in vacuo, w ater (100 cm 3) was added, and the product extracted with dichloromethane (3 x 100 cm 3). Drying of the combined extracts (MgSO 4), filtration through C elite and removal of the solvent on a rotary evaporator gave a dark brown semisolid which was purified by c olumn chromatography (30% EtOAc -hexane, containing 2% v/v dichloromethane) to give an orange -white solid which was recrystallised from EtOAc to give the desired SUBSTITUTED NPHTHALENE (8.10 g) as yellow crystals (mp. 157 -158 °C) in two crops. Lit. 158 -159 °C. 1H NMR/300 MHz/ δ (ppm): 8.79 (1H, d, J 1.1, 1 -H), 7.81 (1H, d, J 1.1, 3 -H), 6.66 (1H, d, J 1.9, 5 -H), 6.51 (1H, d, J 1.9, 7 -H), 4.41 (2H, q, J 7.1, OC H2CH 3), 3.97 (3H, s, OCH 3), 3.91 (3H, s, OCH 3), 2.45 (3H, s, CH3COO) and 1.42 (3H, t, J 7.1, OCH 2CH3). H O CH3O H3CO O O H3CO OCH3 OH O (a) (b) SUBSTITUTED NAPHTHALENE Page 5 of 6 13C NMR/75 MHz/ δ (ppm): 169.2 (CH 3CO), 166.2 (Ar COOEt), 160.9 (6 -C), 157.8 (8 -C), 145.3 (4 -C), 131.0 (4 a-C), 124.4 (2 -C), 123.2 (1 -C), 122.2 (8 a-C), 119.1 (3 -C), 98.5 (7 -C), 91.6 (5 -C), 61.0 ( OCH2CH 3), 55.7 (OCH 3), 55.3 (OCH 3), 20.9 ( CH3COO) and 14.4 (OCH 2CH3). 1. Calculate the percentage yield of step (a) , step (b) and the overall yield of the substituted naphthalene over the two steps. [3] 2. Condensation of aromatic aldehydes with diethyl succinate [step (a)] is called Stobbe Condensation. Please give the detailed reaction mechanism for this reaction. [7] 3. What is Celite? Please google it and explain in not more than a few sentences. [3] 4. The Product of step b, the substituted Naphthalene, was purified by column chromatography, followed by recry stallization. How does recrystalli zation work? Please explain in d etails. [5] 5. The melting point of the product is given as a range within 1 degree Celsius, and not as one value.

Why do you think that is the case? A literature value is also given for compa rison ; what is the significance of this? [2] 6. On the basis of the given 1H- and 13C-NMR spectral data, please decipher the structure of the substituted naphthalene [the product of step (b)]. Give a detailed explanation of how you arrived at the structure. [20] TOTAL 40 MARKS Page 6 of 6 CEM3B20 PRACTICAL ASSIGNMENT 3: SYNTHESIS OF A POLYSUBSTITUTED BENZENE DUE DATE : SATURDAY OCTO BER 1 0, AT 12 :00 MIDNIGHT You are required to synthesize 5.00 grams of 1,2,3 -tribromobenzene, in sev eral steps, with aniline as your initial aromatic precursor as follows: You are allowed to use any acid, base, catalyst, solvent and reagent (organic and inorganic) of your choice. However, in your choice of reagents/solvents, please be mindful of the costs, by -products and waste generated. 1. Give an outline of your step -by -ste p total synthesis of 1,2,3 -tribromobenzene, from aniline [ 12]. 2. (i) For each step, give a brief description of the experimental procedure describing how much of each reagent you would use, in what solvent and at what temperature you would do the reaction. Please list the Safety Precautions of each step . [34 ] (ii) For each step, briefly explain how 1H- and /or 13C-NMR would help you differentiate between your starting material and product for each step in your synthesis . [24 ] TOTAL 70 MARKS NH2 Br Br Br