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National Exams December 2016 BS-12, Organic Chemistry 3 hours duration NOTES: 1. If doubt exists as to the interpretation of any question, the ent candidate is urged to submit with the answer paper, a clear statem of any assumptions made. 2. This is a CLOSED BOOK EXAM. Any non-communicating calculator is permitted. One aid sheet 8.5" x 11" hand-written on both sides. 3. TEN (10) questions constitute a complete exam paper. be The first 10 questions as they appear in the answer book will marked. 4. Each question is of equal value. 04-BS-12/Dec2016 1 of 6 Question 1: Many drugs are Bronsted-Lowry acids or bases. a) What is the most acidic proton in the analgesic ibuprofen? Draw the conjugate base. b) What is the most basic electron pair in cocaine? Draw the conjugate acid. COON ibupraun oc,cairy __ Question 2: THC Is the active component in marijuana and ethanol is the alcohol in alcoholic beverages. Explain why drug screenings are able to detect the presence of THC but not ethanol weeks after these substances have been introduced into the body 1 9H Cit, CKAH2—OH \-P- ImallydrOcannakinc4 THC Question 3: Although penicillin G has two amide functional groups, one is much more reactive than the other. Which amide is more reactive and why? Question 4: Draw the products of each of these SN2 reactions and indicate the stereochemistry where appropriate. 4- d. 04-BS-12/Dec2016 2 of 6 -001i2 Question 5: Propranolol, an antihypertensive agent is used in the treatment of high blood pressure, can be prepared from 1-naphthol, epichlorohydrin and isopropylamine using two successive nucleophilic substitution reactions. Devise a stepwise synthesis of propranolol from these starting materials. OH H Nti2 laapropyiEfrille ,:r11'191 Question 6: What acetylide anion and alkyl halide are needed to synthesize each of the following? ECCH2CH2CH(CH3)2 CH3 b. CH3—C'---- C—C—CH2CH3 c. C'ziC—CH2CH2CH3 Question 7: compounds Devise a synthesis of each compound from acetylene and organic reagents. required other containing two carbons or fewer. You may use any Br OH 04-BS-12/Dec2016 3 of 6 Question 8: Match each compound to its IR-spectrum. Compound F is (CH3CH2) COH pH, 0 o cH3cH2cH2cH2--c-OH cH2=c CH(CH3)2 CH2CH2CH2CH3 (CH3)2CHOCH(CH3)2 -0C(CH3)3 o A Spectrum [11 Spectrum [21 % Transmittance 100 0 4000 3500 3000 2500 2000 1500 Wavenumber (cm-1) 1000 4000 500 3500 Spectrum [31 Spectrum [41 100 100 I /Mit 4000 3500 3000 2500 2000 1500 Wavenumber (cm-1) 0 trTi.. 1000 2500 2000 1500 Wavenumber (cm-1) irtIlltrilt..11TI 4000 500 3000 3500 Spectrum [5] Spectrum [61 100 100 3000 11111,1 2500 2000 1500 Wavenumber (om-1) •s a e 2 50 I f t t1 - 11- 1,{ 0 I t I I f ti t I III- 111 4000 3500 3000 2500 2000 1500 1000 Wavenumber (cm-1) 04-BS-12/Dec2016 50 i.1 500 Wavenumber (cm-1) 4 of 6 1000 1000 Question 9: Treatment of 2-butanone (CH3 COCH2CH3) with a strong base followed by CH3I forms a compound W which gives a molecular ion in its mass spectrum at 86. The IR and 1H NMR spectra of W are given below. What is the structure of W. Explain your reasoning. __..._ H NMR o W 3H 6H 111 fit 4 PPm 1 % Transmittance 8' 3 2500 3000 Wavenumber (cm- ) Question 10: product is 2When 3,3-dimethy1-1-butene is treated with HBr alone, the major and br6mo-2 ' 3-dimethylbutane. When the same alkene is treated with HBr results these Explain 1-bromo-3,3-dimethylbutane. peroxide, the sole product is by referring to the mechanisms. 04-BS-12/Dec2016 5 of 6 Question 11: Synthesize each compound from benzene and any other organic or inorganic reagents. NO2 NH2 a. c. g. e. 3 Br NH2 b. Na f. d. HOOC (PABA) sunscreen component Question 12: Explain the following: a) The pKa of p-nitrophenol is lower than the pKa of phenol (7.2 vs 10). vs b) The pKa of p-nitrophenol is lower than the pKa of m-nitrophenol (7.2 8.3). c) Carboxylic acids A and B are both more acidic than CH3CH2COOH Question 13: a Compound A is a novel poly(ester amide) copolymer that can be used as of er copolym a is A bioabsorable coating for the controlled release of drugs. The ives. four monomers, two of which are amino acids or amino acid derivat polymer body's enzymes recognize the naturally occurring amino acids in the r and the backbone, allowing for controlled enzymatic breakdown of the polyme to used ers monom four the Identify steady release of an encapsulated drug. synthesize A and name the two amino acids. 14 5 poly(ester amide) A 04-BS-12/Dec2016 6 of 6