organic

1. NOVEMBER 2012 55701/MCR1A
Time : Three hours Maximum : 75 marks
PART A — (10 × 1 = 10 marks)
Answer any TEN questions.
All questions carry equal marks.
1. Define atropisomerism.
2. Draw the trans form of cyclooctene.
3. What is meant by prochirality?
4. Write the stable conformation of
1,2-cyclohexandiol.
5. What is preferred conformation of
9–methyldecalin?
6. Give two examples for ambident nucleophile.
7. Complete the following.
(6 pages)

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8. Write a method of generation of benzyne.
9. Give two non-kinetic methods of determining
organic reaction mechanisms.
10. Nitration of acetanilide preferentially gives para
isomer. Why.
11. Predict the product(s) :
12. How will you prepare s-tribromobenzene?
PART B — (5 × 5 = 25 marks)
Answer any FIVE questions.
All questions carry equal marks.
13. Convert the following Fischer projections formulae
into Newmann projection.
(a)

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(b)
(c)
14. Discuss stereoisomerism of allenes.
15. State and explain Cram’s rule with suitable
example.
16. Explain the reactivity of 4-t-butyl-cyclohexanone
towards NaBH4 reduction reaction.
17. Which is undergo the solvolysis in the faster rate
explain?

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18. Explain the Ziegler alkylation reaction suitable
examples.
19. Complete and propose suitable mechanism for the
following reaction
PART C — (4 × 10 = 40 marks)
Answer any FOUR questions.
All questions carry equal marks.
20. Explain stereo selective and stereospecific
reactions with suitable examples.
21. Designate R or S configuration for the following
compounds.
(a)
[P.T.O.]

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(b)
(c)
(d)

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22. Discuss the stereochemistry of decalin and
9–methyldecalin.
23. Write short notes on the following :
(a) Neighbouring group participations
(b) Von-Braun reactions.
24. (a) Write the Hammett equations. Explain the
parameters in this equations.
(b) Explain Chichibabin reaction with suitable
example.
25. (a) Discuss the mechanism of Friedel-Crafts
alkylation.
(b) Write the synthesis of following :
(i) 2-amino-5-methylphenol
(ii) 3-nitro-4-bromobenzoic acid.
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