I IIIIII IIIII IIIII IIIII IIIII IIII IIII

Total

(

x Semester

M.Sc.Ed~

(Chemistry)

/,(

(Scheme:

" Synthetic

Examin'ation,

of Pages

May/June

RIE)

: 3

-2016 ""~

CHEMISTRY Organic

Chemistry

and Molecular

Rearrangement

Time: 3 Hours Instructions

No.

Max. Marks : 80

:

, Ql) Illustrate with examples the specific uses of the foll~wing reagents : i) ii)

Periodic acid Lead Tetraacetate .

iii)

N-Bromosuccinimide

iv)

LithiumAluminuril

[16]

Hydride .

Q2) a)

Discuss the mechanism of the following

reactions giving

examples.

suitable [12]

i)

Cle~ensen

Reduction

ii)

Cis -hydroxylation

iii)

Wolff -Kishner reduction

using Osmium tetroxide

b)

What is oppenauer oxidation? How is it related to MPV reduction? If acetone is used in excess. What is the product formed? Give the I mechanism of the formation ofproduct. [4]

Q3) a)

Discuss the preparation and important uses of the following reagents. [12]

b)

i)

Diazomethane

ii)

Triphenyl phosphine

iii)

Trimethyl Silyl halide

Write a brief note on the importance ofPhase Transfer Catalysts in organic Synthesis.

[4]

P.LO.

.

Q4) a)

b)

Q5)

Explain the following reactions with a suitable example. i)

Petersonreaction

ii)

Woodward hydroxylation

iii)

Sharpless epoxidation

[12]

Write a brief note on the importance of Zeigler -Natta polymerization reactions.

Catalyst in [4]

How will you protect an amino group in organic synthesis? Explain with a suitable example. [4]

a)

b)

Write a brief note on Disconnection Approach.

c)

How do you convert PhCOCH3 to PhCH(CH3)CHO gly~idic ...

ester

condensation.

Suggest

feasible

[6] using Darzen's

mechanism

reactIOn.

for

the

[ 6] OR

Q6) a)

b)

Write short notes on : i)

Keto-enol tautomerism

ii)

Perkin reaction

iii)

Cannizzaroreaction

[12]

How will you synthesise the dipeptide Glycylvaline Groups?

Q7) Discuss the mechanism

using protecting [4]

and applications

reactions. i)

Beckmannrearrangement

ii)

Wagner -Meerwein rearrangement

iii)

Hofmann rearrangement

iv)

Pinacol-Pinacolonerearrangement

of the following

rearrangement r161

.

Q8) a)

b)

( How will you s~thesise the following compounds? Suggest suital;>le mech~sm for the rearrangement reaction involved. l1~] " i) (C~)2C=CHC~ from neopentyl alcohol ii)

P~C(OH)COOH

iii)

C~COOPh

from PhCOCOPh

from CHJCOPh

Comment on the Migratory aptitude of substituents in the rearrangement involving unsymmetricall,2-diols.

[4]

Q9) Write explanatory notes on the following :

[16]

i)

Oxidation of reactive methylene group using SeO2

ii)

Synthesis of ketones using I, 3-dithianes

iii)

Robinson's Annualation reaction

iv)

Ascending the carboxylic acid series by Arndt -Eistert reaction OR Discuss the importance.ofFenton's

" i'

reagent in organic synthesis.. ;/ [4]

QlO)a) b)

Eplain the following reactions with feasible reaction mechanisnli) ii)

c)

Demjanovrearrangement Aldol condensation

[8]

':I -."'.-

What is singlet oxygen? Give the mechanism of reaction of singlet oxygen withER. ' [4]

OOQO

-3-