chem 2262, sections 1 and 2 name key exam 3 april 21, 2003...
TRANSCRIPT
1
Chem 2262, Sections 1 and 2 NAME_____KEY____________EXAM 3 April 21, 2003 Professor___________________
The exam has 6 printed pages of questions, a grading sheet, and 2 tables. Check now to makesure you have all 9 questions and 9 total pages. Put all answers on these sheets. The exam isworth a total of 125 points. Please write your name and other required information on cover pageand page 7.
Multiple Choice (5 points each, 25 points total). Circle the one best answer for each question.1. Which of the following compounds would be the most susceptible towards
nucleophilic attack at the acyl carbon?CH3 Cl
OA) B)
CH3 O
O O
CH3C)
CH3 NH2
OD)
CH3 OCH3
OE)
A-D are of similar reactivity
2. Which of the following is an anhydride?
O O
OO OO
OO
O
O
A B C D3. Which of the following statements concerning nitriles is incorrect?
A) Nitriles can be transformed to carboxylic acids via acid, water and heat.
B) Nitriles can be formed from alkyl halides by nucleophilic substitution by cyanide ion.
C) Nitriles can be reduced with excess lithium aluminum hydride to primary amines.
D) Nitriles can form via cyanide’s preference to react at the α-carbon of an α,β-unsaturated carbonyl.
E) Nitriles can be transformed to carboxylic acids via base, water and heat.
4. Which of the following compounds would be the most acidic?
A) CHF2CH2CH2COOH B) CH2FCHFCH2COOH C) CH3CF2CH2COOH
D) CH3CH2CF2COOH E) CH3CH2CH2COOH
5. Which of the following would not undergo an aldol reaction with benzaldehyde (PhCHO)?
EA B C D
O O O O
B, C and D
2
6. Draw a structure for the major organic product or starting materials as indicatedfor each of the following. Place only one appropriate structure in each box (5points each, 70 points total):
OBr2,
H2O,H3O+
OBr2, excess
H2OOH- excess
+CHBr3 +NaBr + H2O
ONaOH
H2Oheat
crossed aldol condensation product
Ph
O
NaOH
H2Oheat
O
O NaCN
O LiAlH4
C10H16O2
O
Br
O
O
O
O
O
O
CN
OH
3
OCH3
O
CYCLIC DIKETONE 4-CARBON α,β-UNSATURATED CARBONYL
OH
Oheat
n
O
NH
HN
KMnO4
heat
CNH2O
H3O+heat
Cl
O O-Na+
O
O
OR O
OHO
O
O
O O
O
O
O
OHO
OHO H2N
NH2
O
OHO
HO
CO
OH
4
7. (10 points total) Show the complete arrow-pushing mechanism for the followingreaction:
A. Deprotonation to form enolate (4 points)
HO
OH
O + H2O
B. Nucleophilic attack (4 points)
O
O
OCH3
O
C. Protonation to form product alcohol (2 points)
OCH3
O
HOH
OCH3
OH
HO+
ONaOH, H2O O
CH3
H
2OH
5
8. (10 points) Propose an efficient synthesis to effect the following transformation usingany necessary organic or inorganic reagents. Show the product of each synthetic step:
OH
O
O
O
CN
OH
OO
O
CN
Br2, P
Br
OBr
HOO
OBr NaCN
6
9. (10 points total) Propose a structure for the unknown acyl compound whose 1H NMRand IR spectral data are shown below (2 points). Clearly indicate your assignment ofall proton resonances as well by labeling protons a-d on the structure (2 points each).Refer to the attached tables of IR and NMR data if necessary keeping in mind thatchemical shifts are approximate and vary with varying neighboring magneticenvironments.
C5H10O2 1H NMR: (a) triplet δ 1.12 ppm 3H(b) triplet δ 1.27 ppm 3H(c) quartet δ 2.32 ppm 2H(d) quartet δ 4.13 ppm 2H
IR: 1740 cm-1 (strong)
CH3CH2 O
CH2CH3
O D
C BA
