PHARMACEUTICAL CHEMISTRY-II (ORGANIC-I) THEORY Question Papers 4 A.U

Answer question no.1(compulsory) and any four of the remaining. All questions carry equal marks

1. a) Give reasons for the following:

• Ethlyl alcohol gives iodoform reaction whereas n-propyl alcohol does not.
• Dry solvents must be used for the preparation of Grignard's reagents.
• Although HCl is a longer molecule than HF, it has a smaller dipole moment.
• n-Butyl alcohol has a much higher boiling point than its isomer diethyl ether, yet both compounds show the same solubility in water. (4*2=8).

b) Explain geometrical isomerism in detail giving suitable examples.

2. a) Explain SN 1 and SN 2 reactions. Compare and contrast them. b) Explain the method of preparation and mention the uses of i) Iodoform (ii) Diethyl ether.

3. a) Write the structures of the following compounds:

• 3-chloro-2,4-dimethylhexane.
• tert-butyl benzyl ether.
• propylene glycol
• 3-chloro-2-methylpentanol
• (z)-3-chloro-4-methyl-3-hexane
• 4-methyl-2-pentyne
• cis-1,2 dimethyl cyclopropane
• tert-butyl ethyl ether.

b) Explain conformational isomerism giving suitable examples. Discuss the stability of conformational isomer. Discuss the phenomena in cycloalkanes also.

4. (a) Write about the industrial sources of alcohols. (b) Write two methods for the preparation of alcohols. (c) Write about the reaction of alcohols with hydrogen halides. What is the mechanism of this reaction? What is the order of reactivity of alcohols towards hydrogen halides?

5. (a) What is meant by the following?

• Optical activity
• Chirality
• Configuration
• Confirmation

(b) Draw and specify as R and S the enantiomers of (i) Sec-Butyl chloride (ii) Alanine.
(c) Draw stereochemical formulas for all the possible stereoisomers of the following compounds. Label pairs of enantiomers, diastereomers and meso compounds (i) 1,2-dibromopropane (ii) Z-bromo-3-chlorobutane.

6. (a) Write the mechanism of the following reactions:

• Dehydration of alcohols.
• Chlorination of methane
• Hydration of alkenes

(b) Write the reaction of Grignard's reagent with

• Formaldehyde
• Benzaldehyde
• Acetone
• Ethylacetate.

7. (a) Write the reaction of :

• Reduction of 2-butyne
• Hydration of acetylene
• Hydration of 2-butyne

(b) Write the products of ozonolysis of

• Propylene
• 1-butyne
• 2-butene

(c) Write the mechanism of Williamson synthesis.

8. Write short notes on the following:

• Bayer's strain theory
• Stability of conjugated dienes
• Homolysis and heterolysis
• Intra and inter molecular forces.

PHARMACEUTICAL CHEMISTRY-II (ORGANIC-I) THEORY

The subject of organic chemistry will be treated in its modern perspective, keeping for the sake of convenience the usual classification covering the following topics.

Structure and properties of organic molecules: Atomic and molecular orbitals. Bond formation in organic compounds, hybridization, polarity of bonds and molecules, intra and inter molecular forces, influence of structure on physical properties, modern theories of acids and bases, homolysis and heterolysis, types of reagents and reactions, inductive and mesomeric effects; Nomenclature, concepts of isomerism.

Alkanes: Nomenclature, general methods of preperation, energy of activation, transition state, reactions of alkanes with special reference to substitution, free radicals chain reactions, stability of free radicals, bond dissociation energy, free rotation about carbon-carbon single bonds and conformational isomerism, study of composition and uses of liquid paraffin, soft paraffin, white soft paraffin, hard paraffin and ichtammol.

Stereo chemistry: Optical isomerism, chirality, configuration, specification of R and S configuration, sequence rules, diastereomers, meso structures, stereoisomerism.

Cyclo alkanes: Nomenclature, preperation, Bayer's stain theory, chair and boat conformations of cyclohexane, axial and equitorial bonds.

Haloalkanes: Nomenclature, general methods of preparation, nucleophilic substitution, Sn1 and Sn2 mechanisms, E1 and E2 mechanisms for eliminations, preparation and uses of ethyl chloride, chloroform and iodoform.

Alkenes: Nomenclature, two important methods of preparation, structure of ethylene, carbonium ion theory electrophilic and free radical addition to carbon-carbon double bonds, Markovnikav's rule, peroxide effect, ozonolysis, introduction to alkadienes, stability of conjugated dienes, theory of resonance and hyperconjugation.

Alkynes: Nomenclature, acidity and general methods of preparation, structure of acetylene, reactions of alkynes (Formation of metal acetylides, stereo specific reduction of alkynes, addition reactions of alkynes).

Organometallic compounds: Preperation and synthetic applications of Grignard reagent.

Alchohols: Nomenclature, industrial sources, general method of preperation and reactions, study of ethyl alchohol, rectified spirit, industrial spirit, proof spirit, absolute alchohol, benzyl alchohol, cinnamyl alchohol, propylene glycol and glycerol.

Ethers: Nomenclature, general methods of preperation and reactions (Williamson's synthesis and action of HI) , preparation and uses of diethyl ether.