GH 36

LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

SECOND SEMESTER – APRIL 2008

    CH 2951 – CHEM. HETEROCYCLICS AND NATURAL PRODUCTS

 

 

 

Date : 29-04-08                  Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

 

PART-A

 

Answer all the questions                                                 (10 x 2 = 20)

 

1. What are alkaloids? Give an example.
2. What are isoprene and special isoprene rules? How are they useful in predicting the structure of zinziberene?
3. Explain Hoffmann degradation reaction of morphine.
4. Why is electrophilic substitution of pyrrole occurred at position-2 rather than position-3?
5. Give the structures of the products in the following reactions:
   1. quinoline
   2. isoquinoline
6. What are steroids? Mention any one qualitative test for cholesterol.
7. How is the presence of pyrimidine ring in uric acid confirmed?
8. Give the name and structure of any two colour pigments.
9. How is quercetin converted to cyanin chloride?
10. Give the structure of atropine and squalene.

Part – B

Answer any Eight questions                                     (8 x 5 = 40)

11. Explain a) Fischer Indole synthesis b) Bischler Napieralski synthesis of isoquinoline.
12. Complete the following reactions:

papaverine

atropine

13. How is retene synthesized from naphthalene?
14. How will you prove that morphine contains phenanthrene ring?
15. How would you detect isopropylidene, c-methyl and unsaturation present in an unknown terpenoids?
16. Explain the reaction and the products formed by the action of dilute and concentrated KMnO₄ on papaverine.
17. Give the requisite steps involved in the following transformations.
18. i) Coniine picolinic acid
19. ii) Camphoric acid Camphoronic acid
20. How is the structure of hirsutidin chloride elucidated by analytical methods?
21. Explain the synthesis of flavone from alkylated salicylic acid and acetophenone.
22. Explain the oxidative degradation reaction of retene.
23. Write short notes on a) Riemer-Tiemann reaction b) Mannich reaction of pyrrole
24. How is camphoric acid synthesized from 3,3-dimethylglutaric ester?

PART-C

Answer any four the questions                                  (4 x 10= 40)

23. Compare the structure of pyridine and pyrrole and discuss their reactivities towards electrophilic substitution reactions.
24. Write notes on i) Hantzsch synthesis of pyridine ii) Knorr synthesis of pyrrole iii) Skraup’s synthesis of quinoline
25. Explain the structural elucidation of cyanin chloride.
26. How are the following conversions effected?
27. i) Tropine                                3-ethylpyridine
28. ii) Tropine Tropilidine
29. Discuss the structural elucidation of zingiberene.
30. How is squalene converted to lanosterol biochemically?

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