130BL FINAL EXAM

Instructor: Dr. John K.M. Mouser

June 7th, 1999, Winter Quarter

 

 

 

 

 

 

 

 

Place in this box the first two initials of your last name (e.g., if your last

name is SMITH then you would place "SM" in the box).

DO NOT START UNTIL INSTRUCTED TO DO SO!

 

Question

 Points Possible Score Grader's Signature
1. 15 points    
2. 15 points    
3. 10 points    
4. 10 points    
5. 10 points    
6. 10 points    
7. 30 points    
TOTAL: 100 points    

 

1. (15 points) In the first multistep synthesis (formation of tetraphenylnaphthalene), what volume of carbon monoxide (mw = 28.0) is given off if 1.0 gram of benzil (mw = 210) and 1.0 gram of dibenzyl ketone (mw = 210) were used.

Given: mol. wght. of tetraphenylcyclopentadienone = 384 g/mole

Assume: all other reagents are in excess

reaction goes 100% to completion

standard room temperature and pressure

Show your work for full credit.

 

2. (15 points) Give the detailed mechanism for the formation of benzyne starting from anthranilic acid and isopentyl nitrite.

3. (10 points) Benzyne has 8 pi electrons yet it is still aromatic. Explain.

4. (10 points) What products are formed when thionyl chloride is reacted with water.

5. (10 points) What products are formed when acetyl chloride is reacted with water.

6. (10 points) What is the exact mass of methyl m-nitrobenzoate?

7. Compound W is an unknown. It was determined that the base peak has a molecular formula of C7H13. Given the IR, MS and carbon-13 spectrum, answer the following questions:

a. (3 pts) What is the molecular weight of compound W? _______________

b. (3 pts) What is the molecular formula of compound W _______________

c. (3 pts) Which of the below peaks in the MS is the parent peak? _______________

PLACE YOUTR ANSWER IN THIS BOX

 

e. (9pts) Supply structures for in the MS peaks at 83, 97, 179.

 

 

 

 

 

 

 Peak at 83

  

 

 

 

 

 

Peak at 97

  

 

 

 

 

 

Peak at 179

Mass Spetrum

IR Spectrum of Compound W

Carbon-13 NMR (proton decoupled) of Compound W

Detection Presence of Isotopes:

Element Isotope Exact Mass Abundance
Hydrogen 1H

2H

3H

 1.00783

2.01410

3.01605

 99.985

0.015

trace
Carbon 12C

13C

14C

 12.00000

13.00336

14.00324

 98.90

1.10

trace
Nitrogen 14N

15N

 14.0031

15.0001

 99.632

0.368
Oxygen 16O

17O

18O

 15.9949

16.9991

17.9992

 99.762

0.038

0.200
Fluorine 19F 18.9984 100.000
Sulfur 32S

33S

34S

 31.9721

32.9715

33.9679

 94.93

0.76

4.29
Chlorine 35Cl

37Cl

 34.9689

36.9659

 75.77

24.23
Bromine 79Br

81Br

 78.9183

80.9163

 50.69

49.31
Iodine 127I 126.9045 100