LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 51

M.Sc. DEGREE EXAMINATION – CHEMISTRY

FOURTH SEMESTER – APRIL 2007

CH 4954 / 4951 – HETEROCYCLIC & NATURAL PRODUCTS

Date & Time: 27/04/2007 / 9:00 – 12:00      Dept. No.                                                Max. : 100 Marks

 

 

PART – A

Answer ALL questions                       (10 ´ 2 = 20 marks)

1. How would you convert 1,1,3,3- tetraethoxy propane into pyrazole?
2. How would you synthesis antipyrine from ethyl acetoacetate?
3. How would you prepare uracil from urea?
4. Explain Hoffmann exhaustive methylation method with an example.
5. What are the uses of atropine?
6. How would you confirm the presence of methylenedioxy group in peepuloidin?
7. What happens when cadenine is treated with sulphur?
8. Give the stereo chemical structure of Gibberellic acid.
9. What are the different ring systems present in the cholesterol?
10. How would you prove the presence of ketonic group in cortisone?

 

PART – B

Answer any EIGHT questions                (8 ´ 5 = 40 marks)

11. How would you prepare alloxan from barbituric acid?
12. How would you prepare flavones by Baker-Venkataraman synthesis?
13. How would you effect the following conversion?

Coumarin      ¾¾¾¾®   anthocyanadin

14. What happens when imadazone is treated with
    a) PhCOCl, NaOH      and        b) H₂O₂
15. Explain Willstatter synthesis of tropine.
16. Establish the structure of heptaphylline with synthesis.
17. Explain the synthesis of papaverine.
18. Explain the Nametkin rearrangement with a suitable example.
19. Give the structure of Vitamin-A. How would you establish its structure by synthesis?
20. Explain the synthesis of oestrone.
21. What are the different molecular rearrangements involved in steroids? Explain any one with
    a suitable example.
22. Explain the ring junction stereochemistry in steroids with suitable examples.

PART – C

Answer any FOUR questions                 (4 ´ 10 = 40 marks)

23. a) How would you obtain uric acid from urea?
    b) Establish the structure of belladine.
24. a) Explain the electrophilic substitution reactions in xanthione.
25. b) Establish the structure of cocaine by synthesis.
26. a) Explain the ring cleavage reactions in uric acid.
    b) Establish the structure of abietic acid.
    26.       Explain all steps involved in the total synthesis of cholestrol.
27. How would you synthesis cortisone from 3-methyl penta-1,3- diene? Explain the steps with mechanism.
28. Establish the structure of camphor with synthesis.

 

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