LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc., DEGREE EXAMINATION – CHEMISTRY

FIFTH SEMESTER – NOVEMBER 2012

CH 5505 – ORGANIC FUNCTIONAL GROUPS – II

 

 

 

Date : 01-11-2012              Dept. No.                                        Max. : 100 Marks

Time : 9.00 – 12.00

 

PART – A

Answer ALL questions:                                                                                            (10 × 2 = 20)

 

1. How will you prepare ethylamine by Gabriel phthalimide synthesis?
2. How will you prepare diphenyl amine?
3. Methyl amine is more basic than aniline.Explain.
4. What are erythro and threo isomers?
5. Are all substances with chiral atoms optically active and resolvable?Explain.
6. What is meant by tautomerism?Give an example.
7. Give an example of molecular rearrangement involving migration of a group from oxygen atom to aromatic ring.
8. What is isoprene rule?
9. What are alkaloids?
10. Suggest any two tests to prove the presence of alkaloids.

 

PART – B

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

 

11. Arrange the following compounds in decreasing order of basicity and give reasons

for your answer.

Aniline , p-nitro aniline , m- nitro aniline , p-methyl aniline

12. Starting from aniline how will you synthesize the following?
13. i) sulphanilic acid
14. ii) benzoic acid

iii) phenyl isocyanate

13. Explain why racemic tartaric acid can be resolved but not meso tartaric acid. Give the chemical method of resolution.
14. Differentiate between enantiomers and diastereomers by taking suitable examples.

 

15. What happens when the following pair undergoes Claisen condensation?

Ethyl formate and ethyl acetate. Suggest a suitable mechanism.

16. What do you understand by active methylene group? Highlight its significance in organic synthesis.
17. Discuss the mechanism of pinacol – pinacolone rearrangement and give the evidence for carbonium ion intermediate.
18. Discuss Claisen rearrangement and give suitable evidence to confirm that the rearrangement is intramolecular.
19. Electrophilic substitution takes place in C-2 position and not in C-3 position in Furan. Explain.
20. Outline the synthesis of nicotine.
21. Explain the role of Herzig-Meyer method and Zeisel’s method in the structural elucidation of alkaloids.
22. Discuss the mechanism of nitration of benzene and explain why nitro group is a

deactivating group.

 

                                                            PART – C      

Answer any four questions:                                                                                    (4 × 10 = 40)

 

23. Give an example for the following name reaction.
24. Sandmeyer reaction ii)  Gomberg reaction

• Gattermann reaction iv) Carbylamine reaction

1. Schiemann reaction

 

24. a) How will you synthesize ortho and meta dinitro benzene from benzene . (6)
25. b) How will you distinguish primary secondary and tertiary amines by Hinsberg

method.                                                                                                                                 (4)

 

25. a) Explain asymmetric synthesis with suitable examples. (6)
26. b) Discuss the stereo chemistry of Walden inversion                                           (4)

 

26. How will you prepare the following from acetoacetic ester?
27. Acetonyl acetone ii) n-butyric acid       iii)  antipyrine
28. 3-methyl 2-pentanone v) Succinic acid
29. Complete the following:
30. Furan + maleic anhydride à ii) Pyrrole + C₆H₅N₂Cl + NaOH à

iii) Quinoline +KMnO₄à                  iv) Pyridine + nC₆H₅Li à

1. Thiophene + H₂SO₄ à
2. a) Explain the following rearrangements with mechanism.             (6)
3. Benzilic acid    ii) Beckmann.
4. b) Write the structure of piperine and give its synthesis. (4)

 

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