Organic Compound Identification and NMR Spectra Analysis, Lecture notes of Chemistry

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Practice Exams From 2013-

Chemistry 3720 Practice Exam 1 Name:

This exam is worth 100 points out of a total of 600 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam and you may use the attached spectroscopy sheet as needed. Good Luck.

1. (8 points) Give the major final products from the following and explain the different regiochemical outcomes in terms of the mechanism(s) operating. (Klein Chapter 14)

3. (16 points) Give the expected major product from each step of the following reaction sequence. No need to show any mechanisms. (Klein Chapter 13)
4. (9 points) Give the expected final product(s) formed in each of the following cases. (Klein Chapter 14)

5. (7 points) Give the expected major product formed under the following reaction conditions, and then a detailed mechanism for the conversion. How would you tell the product is an alcohol by IR spectroscopy? (Klein Chapters 13-15)
6. (8 points) A recently isolated microbial metabolite is found to have the empirical formula C 4 H 7 O and its mass spectrum shows M+^ = 142. Significant signals are seen in the IR spectrum at 1740 and 1650 cm-1. The 1 H NMR spectrum, collected in CDCl 3 , is given below. Provide a structure for the organic compound that matches the data, and then match the protons in the molecule to the 1 H NMR signals. (Klein Chapter 15)

Unsaturation number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

(^1) H NMR (ppm): 1.06 (d, 6H, J = 7.1 Hz), 1.36 (t, 3H, J = 7.0 Hz), 2.52 (octet, 1H, J = 7.1 Hz), 4.20 (q, 2H, J = 7.0 Hz), 5.83 (d, 1H, J = 16.0 Hz), 6.88 (dd, 1H, J = 7.1, 16.0 Hz)

8. (20 points) Give the major organic product(s) expected from each step in the following reactions. You do not have to show any mechanisms. (Klein Chapters 13 and 14)

Chemistry 3720 Practice Exam 1 - Key Name:

This exam is worth 100 points out of a total of 600 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam and you may use the attached spectroscopy sheet as needed. Good Luck.

1. (8 points) Give the major final products from the following and explain the different regiochemical outcomes in terms of the mechanism(s) operating. (Klein Chapter 14)

3. (16 points) Give the expected major product from each step of the following reaction sequence. No need to show any mechanisms. (Klein Chapter 13)
4. (9 points) Give the expected final product(s) formed in each of the following cases. (Klein Chapter 14)

5. (7 points) Give the expected major product formed under the following reaction conditions, and then a detailed mechanism for the conversion. How would you tell the product is an alcohol by IR spectroscopy? (Klein Chapters 13-15)

The product would have a broad absorption at ~3600 cm-1^ in the IR spectrum

6. (8 points) A recently isolated microbial metabolite is found to have the empirical formula C 4 H 7 O and its mass spectrum shows M+^ = 142. Significant signals are seen in the IR spectrum at 1740 and 1650 cm-1. The 1 H NMR spectrum, collected in CDCl 3 , is given below. Provide a structure for the organic compound that matches the data, and then match the protons in the molecule to the 1 H NMR signals. (Klein Chapter 15)

Unsaturation number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

(^1) H NMR (ppm): 1.06 (d, 6H, J = 7.1 Hz), 1.36 (t, 3H, J = 7.0 Hz), 2.52 (octet, 1H, J = 7.1 Hz), 4.20 (q, 2H, J = 7.0 Hz), 5.83 (d, 1H, J = 16.0 Hz), 6.88 (dd, 1H, J = 7.1, 16.0 Hz)

8. (20 points) Give the major organic product(s) expected from each step in the following reactions. You do not have to show any mechanisms. (Klein Chapters 13 and 14)

Chemistry 3720 Practice Exam 2 Name:

This exam is worth 100 points out of a total of 600 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam and you may use the attached spectroscopy sheet as needed. Good Luck.

Unsaturation number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

1. (10 points) Give the expected major product(s) from the following nitration reaction, and then give a complete mechanism for the conversion that includes resonance structures for the intermediate(s) formed. Explain why you only get certain isomer(s) as the major product(s) in this reaction. (Klein Chapter 19)

4. (20 points) Give the major organic product(s) expected from each step in the following reaction sequences. You do not have to show any mechanisms here. (Klein Chapters 17-19)

5. (12 points) Provide syntheses of the compounds below, starting from benzene, that show each product formed along the way. You have access to all of the usual reagents in the lab (e.g. HNO 3 , Br 2 , NaOH, AlCl 3 , etc.), as well as techniques for separating any isomers and byproducts as needed. (Klein Chapter 19)
6. (12 points) Give the products from each step of the following synthetic sequence and then, on the NMR axis given below, draw the expected 1 H spectrum of the final product. (Klein Chapters 13 and 16)

8. (10 points) Provide a retrosynthetic plan for the molecule shown that goes back only to the organic compounds provided, and then show how you would build the molecule using chemistry seen in 3719 and
   3720. (Klein Chapter 19)
9. (6 points) Indicate which of the following molecules are aromatic and explain your choices based on applying Hückels’rule. (Klein Chapter 16)

Chemistry 3720 Practice Exam 2 Key Name:

This exam is worth 100 points out of a total of 600 points for Chemistry 3720/3720L. You have 50 minutes to complete the exam and you may use the attached spectroscopy sheet as needed. Good Luck.

Unsaturation number = [#C atoms – ½#H atoms – ½#Halogen atoms + ½#N atoms] + 1

1. (10 points) Give the expected major product(s) from the following nitration reaction, and then give a complete mechanism for the conversion that includes resonance structures for the intermediate(s) formed. Explain why you only get certain isomer(s) as the major product(s) in this reaction. (Klein Chapter 19)