JNTU
JNTU B.Pharmacy II PHARMACEUTICAL ORGANIC CHEMISTRY-II Previous Question Paper (September/October - 2023 - R17)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
What is Friedel-crafts acylation? Explain.
Answer
Friedel-Crafts acylation is an electrophilic aromatic substitution reaction where an acyl group (RCO-) is introduced into an aromatic ring. The reaction typically involves the treatment of an aromatic compound with an acyl halide or acid anhydride in the presence of a Lewis acid catalyst, such as anhydrous aluminum chloride (AlCl3).
The Lewis acid coordinates with the acyl halide to generate an acylium ion (R-C≡O+), which acts as the electrophile that attacks the aromatic ring to form a ketone.
Define activating group? Give examples.
Answer
An activating group is a substituent that increases the electron density of an aromatic ring, thereby making the ring more reactive toward electrophilic aromatic substitution compared to benzene. These groups typically donate electrons to the ring through either the inductive effect or resonance, which stabilizes the positively charged carbocation intermediate formed during the reaction.
Common examples include:
- Strongly activating: -NH2, -NHR, -NR2, and -OH.
- Moderately activating: -OCH3 (alkoxy groups) and -NHCOCH3 (amides).
- Weakly activating: -CH3, -C2H5 (alkyl groups).
Give synthetic uses of aryl diazonium salts.
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Give the structure and uses of m-cresol and ß-napthol.
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Define saponification value. Give its significance.
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Classify fats and oils with examples.
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Give the structure and uses of one medicinally important phenanthrene derivatives.
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Write any two reactions of Triphenylmethane.
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How do you calculate the angle in cyclopropane?
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Write on the addition reaction of cyclobutane with halogens.
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Part B
Explain the reaction and mechanism of Friedel craft’s alkylation with its Limitations.
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Explain the reaction and mechanism of halogenation of benzene.
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Explain aromaticity and resonance of benzene.
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Discuss the orientation effect of Hydroxyl and amino group in benzene.
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What are phenols? Explain acidity of phenols.
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What are aromatic amines explain basicity of aromatic amines.
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Explain the reactions of aromatic amines.
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Discuss the qualitative test of phenol.
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Explain significance and reactions of hydrolysis and hydrogenation of fat.
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Explain the determination of acid value with its significance.
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Explain the determination of Esterification value with its significance.
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Write a note on Reichert Meissl (RM) value.
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Depict the synthesis of Phenanthrene.
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Write any three methods for synthesis of Diphenyl methane.
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Give Haworth synthesis and reactions of Naphthalene.
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Resonance hybrid structure for Phenanthrene and write about its Resonance energy.
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Write a note on Sachse Mohr’s theory.
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Describe about Coulson and Moffitt’s modification.
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Explain the stability of cyclo alkanes on the basis of Bayer strain theory.
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Draw the picture of: i) Stable cyclohexane ii) Angle strain in Cycloalkanes.
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