Ph.D. Course Work Examination Jan/Feb-2018
CHEMISTRY (Paper II)
Recent Trends in Organic Chemistry
Day Date: Wednesday, 17-01-2018
Max. Marks: 100
Time: 11.00 AM to 02.00 PM
Instructions: Attempt in all five questions. All the questions carry equal marks. Figures to the right indicate full marks.
Q.1

Discuss the stereochemistry of yohimbine.
10

Answer the following (any two)
10
Explain stereospecific and stereoselective reactions with respect to alkene and cholestan-3-one.
Draw the conformational structure of olenane and discuss the stereochemistry of ring fusions in it.
Explain the stereochemistry of the following reaction with respect to Asymmetric synthesis.
Q.2

Explain the synthetic utility of phosphorus silicon organometallic reagents.
10

Answer the following (any two)
10
Explain with mechanism the ozonolysis of carbon-carbon double bond.
What is meant by IPSO substitution? Explain with respect to 1-chlro-2, 4-dinitrobenzene.
Explain the mechanism of the following reaction and write the type of Rearrangement.
Q.3

Explain in detail with example the factors that influence the C=O stretching vibration.
10

Answer the following (any two)
10
Benzene is colourless but its isomer, fulvene is yellow, Justify
Molecular formula C11H14O3
UV∶225nm (ε 9000)
3200−2800 broad ,2720,1710,1610,1510,850 1m−1
2.63 Hz,12 mm ,3.78 s,18 mm ,6.75 d,J=8Hz,12 mm 7.05 d,J=8Hz,12 mm ,12.1(s,6 mm)
1.95 quintet,J=6 Hz,12 mm ,2.25 Hz,12 mm
Molecular formula C11H11NO2
1707 cm−1 2.4(s,3H) 189,137,91,55
Q.4

What are COSY, NOESY Experiments? Explain with examples.
10

Answer the following (Any two)
10
Explain Nuclear overhauser effect with an example.
Explain off Resonance Decoupling Experiment with an example.
What is DEPT spectrum? Explain different type of DEPT spectra with suitable Example.
Q.5

Describe important feature of the mass spectrum of Aldehyde and Ketones. Write fragmentation modes of various types of Aldehydes and Ketones with examples.
10