JNTU
JNTU B.Pharmacy II PHARMACEUTICAL ORGANIC CHEMISTRY-III Previous Question Paper (December - 2019 - R17)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
Define optical activity. Write the criteria for a compound to exhibit it.
Answer
Optical activity is the ability of a substance to rotate the plane of plane-polarized light. For a compound to exhibit optical activity, it must possess molecular chirality, meaning it lacks an internal plane of symmetry, center of symmetry, or alternating axis of symmetry.
What is enantiomerism? Explain with suitable examples.
Answer
Enantiomerism is a form of stereoisomerism where two molecules are non-superimposable mirror images of each other, known as enantiomers. These compounds share identical physical properties but rotate plane-polarized light in opposite directions. A classic example is lactic acid, which exists as (+)-lactic acid and (-)-lactic acid.
What is cis-trans isomerism? Explain with suitable examples.
Answer
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Outline the conformational isomerism in ethane.
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Define heterocyclic compounds. Outline the structure of pyrrole.
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Describe the structure, nomenclature and medicinal uses of thiophene.
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Outline the structure, nomenclature and medicinal uses of imidazole.
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Outline one synthetic method for pyridine.
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What is birch reduction?
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Give the preparation method of sodium boro hydrate.
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Part B
Explain the following with an example: a) Diasterioisomerism b) Mesocompounds c) Polarimeter d) Chiral and Achiral compounds.
Answer
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Explain DL system and nomenclature of optical isomers. Give any one reaction of chiral molecules.
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Describe EZ, syn and Anti systems of Geometric isomerism with suitable examples.
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Describe the conformational isomerism in n-butane and cyclobutane.
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Explain the synthesis, reactions, aromaticity and medicinal uses of Furan.
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Write the synthesis, suitable reactions, relativity aromaticity and basicity of pyrrole.
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Give the synthesis, reactions and medicinal uses of pyrazole.
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Write the synthesis, reactions and medicinal uses of pyrimidine.
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Outline the following named reactions with its applications: a) Wolf kishner reduction b) Diakin reaction
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Explain the following rearrangements: a) Beckman rearrangement b) Schmidt rearrangement.
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