LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

LM 19

SIXTH SEMESTER – APRIL 2006

                                                        CH 6604 – NATURAL PRODUCTS

(Also equivalent to CHE 604)

 

 

Date & Time : 24-04-2006/9.00-12.00         Dept. No.                                                       Max. : 100 Marks

PART – A

Answer ALL the questions.                                                               (10 X 2 = 20)

1. Explain isoprene rule with respect to geraniol.
2. Draw the structure of piperonylic acid and caffeine.
3. Predict the product for the reaction between anthracene and maleic anhydride.
4. How is the presence of unsaturation tested in alkaloids?
5. How is urea converted into parabanic acid?
6. Give the resonance structure of naphthalene.
7. Apply Huckel’s rule to predict the aromatic character of thiophene and explain.
8. How is 2-aminopyridine obtained from pyridine?
9. What is nicotinic acid? How is it obtained?
10. What are alkaloids? Give an example for pyridine alkaloid.

PART – B

Answer any EIGHT questions only.                                                   (8 X 5 = 40)

11. Explain Hoffmann’s exhaustive methylation of coniine.
12. Naphthalene on sulphonation at 50 ⁰C and at 150 ⁰C yields different products. Explain.
13. What are carcinogens? Explain the carcinogenic activity of polynuclear hydrocarbons.
14. How is anthracene obtained by Haworth’s synthesis?
15. Resonance energy of benzene is 36 kcal mol^-1 while that of naphthalene is 61 kcal mol^-1. Explain.
16. Electrophilic substitution of pyridine yields 3- substituted product. Explain.
17. Explain the synthesis of uric acid.
18. Write note on anthocyanins.
19. How are the following obtained from pyrrole:
20. Pyrrole-2-carboxylic acid. b. 2-Formylpyrrole.
21. How is the presence of two benzene rings established in naphthalene?
22. Account for the products of oxidation of quinoline with acidified potassium permanganate.
23. How are terpenes isolated?

 

PART – B

Answer any FOUR questions only.                                                     (4 X 10 = 40)

23. Establish the structure of uric acid.
24. Elucidate the structure of nicotine.
25. Describe the constitution of citral.
26. a. Discuss the structure of piperic acid.
27. Write a note on flavones.
28. Explain the following:
29. Skraup’s synthesis b. Conversion of thiophene to thiophene-2-carboxylic acid.

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc.

LM 21

DEGREE EXAMINATION –CHEMISTRY

SIXTH SEMESTER – APRIL 2007

CH 6604 – NATURAL PRODUCTS

 

 

Date & Time: 20/04/2007 / 9:00 – 12:00          Dept. No.                                                     Max. : 100 Marks

 

 

 

 

PART-A                                      

Answer ALL questions.                                                                                              (10×2=20)

1. What happens when naphthalene is treated with ozone?
2. How will you synthesise phenanthrene from benzil?
3. Write any one example for ring expansion reaction of pyrrole.
4. How does thiophene react with mandelic anhydride?
5. What are alkaloids? How are they classified?
6. How are terpenoids isolated?
7. Write any four properties of nicotine.
8. What is isoprene rule?
9. Write the basic structure of flavone and flavonol.
10. What are natural pigments? Give an example.

 

PART-B

Answer any EIGHT questions.                                                                                  (8×5=40)

11. Explain the Hawarth synthesis of naphthalene.
12. What happens when the following reagents are treated with pyrrole?

(a) SO₂Cl₂/ether  (b) K₂CO₃/heat   (c) CHCl₃/aq.KOH  (d) C₆H₅N₂Cl   (e) SO₃/pyridine

13. Write a note on Hofmann’s exhaustive methylation method of degradation of alkaloids.
14. Explain the synthesis of piperic acid from catechol.
15. What are terpenoids? How are they classified on the basis of the number of isoprene units?
16. Write short notes on isolation of essential oils from plants?
17. How is camphor synthesized from camphoric acid?
18. Give the different products obtained on the oxidative degradation of α-pinene.
19. Explain the synthesis of menthol.
20. Explain the biological importance of anthocyanines.
21. Write a note on carcinogenic hydrocarbons.
22. Elucidate the structure of caffeine.

PART-C                                                 

Answer any FOUR questions.                                                                                   (4×10=40)

23. a) Explain the orbital structure of naphthalene. (5)
24. b) Draw the flow chart of isolation of anthracene. Explain. (5)
25. Discuss the constitution and importance of nicotine.
26. Elucidate the structure of camphor.
27. Explain the structure and synthesis of cyanidine chloride.
28. Discuss the structure of quercetin.
29. Elucidate the structure of uric acid.

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – CHEMISTRY

GH 24

SIXTH SEMESTER – APRIL 2008

CH 6604 – NATURAL PRODUCTS

 

 

 

Date : 23/04/2008                Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

 

PART – A

Answer all the questions.                                          (10  ´ 2   = 20)

 

1. Write the products obtained when anthracene is reduced using sodium –amalgam and isopentanol.
2. Give the name and structure of any two very potent cancer producing polycyclic hydrocarbons.
3. Give the products obtained when pyridine reacts with sodium amide.
4. How wil you determine the number of double bonds present in the alkaloid piperine.
5. What is isoprene rule ? Indicate the isoprene units in the structure of citral.
6. How will you synthesize α- terpineol from α -pinene.
7. What are purines ? Write the structure of Caffeine.
8. Give any two biological importance of anthocyanins.
9. Write the products obtained when uric acid is oxidized using dil.HNO3.
10. Write the structure of cyanidine chloride

 

PART – B

Answer any Eight questions                     (8  ´  5   = 40)

 

11. How will you synthesize anthracene from Phthalic anhydride using Friedel – Craft’s reaction.
12. Complete the following reactions.

 

13. i. How is thiophene manufactured from acetylene ?
14.       How will you synthesise quinoline using Skraup’s synthesis method.
15. i. Explain why are pyrrole,furan and thiophene classified as aromatic compounds.
16.          How will you prepare pyridine from pyrrole.
17. Identify the products in the following reactions.
18. Quinoline               A
19. Pyridine   +   Acetyl chloride     B

iii.     Pyridine   +  C₆H₅ Li     C

16. i. What happens when citral is subjected to oxidation with Alk. KMnO₄ followed by chromic acid? Write the name and structure of the products formed.
17. What happens when menthol is heated with KHSO₄
18. Briefly discuss the constitution of Geraniol.
19. i. What are terpenes ?  How are they classified ?
20.   How will you establish the position of double bonds in citral.
21. Write short notes on Flavones and Flavonoids.
22. Give any one method for the synthesis of cyanidine chloride.
23. How will you synthesize Xanthine from urea using Traube’s method.
24. i. What are the products obtained when Caffeine is oxidized using potassium chlorate in HCl.
25.   How will you synthesize Caffeine from uric acid using Fischer method.

PART – C

Answer any four questions.                                 ( 4 ´ 10 = 40 )

 

23. Elucidate the structure of phenanthrene. Confirm it by Haworth and Pschorr’s synthesis.
24. i. Deduce the orbital structure of pyrrole.
25. Give any one method for the synthesis of piperine.
26. Elucidate the structure of menthol.
27. What are anthocyanins? Discuss the structure and any two general methods of synthesis of anthocyanins.
28. Establish the structure of iso-quinoline.
29. Elucidate the structure of uric acid.

 

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