LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 38

M.Sc. DEGREE EXAMINATION – CHEMISTRY

SECOND SEMESTER – APRIL 2007

                         CH 2951 – CHEMISTRY OF HETEROCYCLICS AND NATURAL PRODUCTS

 

 

 

Date & Time: 24/04/2007 / 1:00 – 4:00      Dept. No.                                       Max. : 100 Marks

 

 

PART-A

 

Answer all the questions                                                 (10 x 2 = 20)

 

1. What are terpenoids? Give an example.
2. What are isoprene and special isoprene rule? How are they useful in predicting the structure of cadienine?
3. What is the end product of Hoffmann degradation of N-methylpiperidine?
4. Why pyridine is less reactive than benzene towards eletrophiles?
5. Give the structures of the products in the following reactions:
6. a) quinoline KMnO₄
7. b) isoquinoline      KMnO₄
8. What are ureides and purines? How are they related?
9. Mention any two qualitative test for cholesterol.
10. What are harmones?
11. What are iodine value and polenski value?
12. Give the structure of atropine

 

PART – B

Answer any Eight questions                                     (8 x 5 = 40)

 

11. Explain a) Fischer Indole synthesis b) Skraups’ synthesis of quinoline.
12. Complete the following reactions:

Imidazole + 2 C₆H₅COCl + 3NaOH

Imidazole + H₂O₂

13. What are the different products formed from the ozonolysis reaction of squalene? Give the molecular structure also.
14. How will you prove morphine contains phenanthrene ring?
15. How is tropine converted to 2-ethylpyridine?
16. Explain the reaction and the products formed by the action of dilute and concentrated KMnO₄ of papaverine.

 

17. Explain the Robinson method of synthesizing anthocyanidine.
18. Explain the synthesis of flavone from alkylated salicylic acid and acetophenone.
19. Explain the structural relationship between flavonols(quercetin) and anthocyanidine(cyanidine chloride)
20. Write the structural formula of pyrimidine. How is it obtained from barbituric acid.
21. Write short notes on a) Riemer-Tiemann reaction b) Mannich reaction of pyrrole
22. How is camphoric acid synthesized from 3,3-dimethylglutaric ester?

 

PART-C

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

 

23. Compare the reactivity of furan, thiophene and pyrrole in electrophilic substitution reactions.
24. a)Account for the fact that pyridine undergoes electrophilic substitution at the β-position. b)Write notes on Hantzsch synthesis of pyridine and Knorr synthesis of pyrrole.
25. Explain the structural elucidation of cyanidine chloride.
26. How is the structure of tropine established?
27. Discuss the structural elucidation of morphine.
28. How is the structure of Gibberilic acid established?

 

 

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