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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LM 38

M.Sc. DEGREE EXAMINATION – CHEMISTRY

SECOND SEMESTER – APRIL 2007

                         CH 2951 – CHEMISTRY OF HETEROCYCLICS AND NATURAL PRODUCTS

 

 

 

Date & Time: 24/04/2007 / 1:00 – 4:00      Dept. No.                                       Max. : 100 Marks

 

 

PART-A

 

Answer all the questions                                                 (10 x 2 = 20)

 

1. What are terpenoids? Give an example.
2. What are isoprene and special isoprene rule? How are they useful in predicting the structure of cadienine?
3. What is the end product of Hoffmann degradation of N-methylpiperidine?
4. Why pyridine is less reactive than benzene towards eletrophiles?
5. Give the structures of the products in the following reactions:
6. a) quinoline KMnO₄
7. b) isoquinoline      KMnO₄
8. What are ureides and purines? How are they related?
9. Mention any two qualitative test for cholesterol.
10. What are harmones?
11. What are iodine value and polenski value?
12. Give the structure of atropine

 

PART – B

Answer any Eight questions                                     (8 x 5 = 40)

 

11. Explain a) Fischer Indole synthesis b) Skraups’ synthesis of quinoline.
12. Complete the following reactions:

Imidazole + 2 C₆H₅COCl + 3NaOH

Imidazole + H₂O₂

13. What are the different products formed from the ozonolysis reaction of squalene? Give the molecular structure also.
14. How will you prove morphine contains phenanthrene ring?
15. How is tropine converted to 2-ethylpyridine?
16. Explain the reaction and the products formed by the action of dilute and concentrated KMnO₄ of papaverine.

 

17. Explain the Robinson method of synthesizing anthocyanidine.
18. Explain the synthesis of flavone from alkylated salicylic acid and acetophenone.
19. Explain the structural relationship between flavonols(quercetin) and anthocyanidine(cyanidine chloride)
20. Write the structural formula of pyrimidine. How is it obtained from barbituric acid.
21. Write short notes on a) Riemer-Tiemann reaction b) Mannich reaction of pyrrole
22. How is camphoric acid synthesized from 3,3-dimethylglutaric ester?

 

PART-C

Answer any four the questions                                  (4 x 10= 40)

 

23. Compare the reactivity of furan, thiophene and pyrrole in electrophilic substitution reactions.
24. a)Account for the fact that pyridine undergoes electrophilic substitution at the β-position. b)Write notes on Hantzsch synthesis of pyridine and Knorr synthesis of pyrrole.
25. Explain the structural elucidation of cyanidine chloride.
26. How is the structure of tropine established?
27. Discuss the structural elucidation of morphine.
28. How is the structure of Gibberilic acid established?

 

 

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      LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

WD 35

M.Sc. DEGREE EXAMINATION – CHEMISTRY

SECOND SEMESTER – April 2009

          CH 2953 / 2951- CHEMISTRY OF HETEROCYCLICS AND NATURAL PRODUCTS

 

 

 

Date & Time: 27/04/2009 / 1:00 – 4:00   Dept. No.                                                   Max. : 100 Marks

 

 

 

 

PART-A                                      

Answer ALL questions.                                                                                              (10 x 2 = 20)

 

1. Write the IUPAC name of the following compounds:

 

2. Why does the electrophilic attack of pyrimidine at C-5 preferred?
3. What are alkaloids? Give an example for alkaloid does not contain nitrogen atom in the ring.
4. Mention any two functions of morphine.
5. Explain the importance of Tilden’s reagent in the elucidation of terpenoids.
6. What are diterpenoids? How is it differentiated from monoterpenoids?
7. Write a note on: Classification of hormones.
8. Draw the structure and write any two functions of cortisone.
9. What happens when anthocyanidin is fused with hot KOH?
10. How is isoflavone synthesized?

 

 

                                                                      

                                                                       PART-B                                      

Answer ANY EIGHT questions.                                                                                 (8 x 5 = 40)

 

11. Write short notes on: Spectral properties of heterocyclic compounds.
12. Orientation in nucleophilic substitution of pyridine at the 2- or 4- position is preferred. Why? Explain.
13. Explain the acidic and basic character of azoles.
14. How are alkaloids extracted from plants? Explain.
15. Explain the structure of belladine.
16. Elucidate the structure of atropine.
17. How is zinziberene synthesized? Explain.
18. Write a note on: a) Classification of terphenes       b) General characteristics of terpenoids
19. Equatorial hydroxyl and carboxyl groups of sreroids are esterified more readily than the axial groups. Why? Explain.
20. Give the structure and any two functions of oestrone and progestrone.
21. Explain the amphoterric nature of cyanidin chloride with mechanism.
22. Discuss the structure of flavonol.

 

 

 

 

 

 

 

 

PART-C                                    

Answer ANY FOUR questions.                                                                                  (4 x 10 = 40)

 

23. a) Predict the products of the following reactions:           (5×1)
24. b) How will you synthesize coumarins? (5)
25. a) How does uric acid is formed in human body? Explain. (5)
26. b) Discuss the constitution of ecgonine. (5)
27. Elucidate the structure of Morphine.
28. Discuss the structural elucidation of camphor.
29. a) Secondary axial hydroxyl groups are more readily oxidized by chromic acid than secondary equatorial hydroxyl groups in steroids. Explain. (4)
30. b) How does the IR and UV spectra used in conformational analysis of steroids? Explain with cotton effect. (6)
31. Explain the general method to determine the structure of anthocyanidin.

 

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

SECOND SEMESTER – APRIL 2012

CH 2953 – CHEMISTRY OF HETEROCYCLICS AND NATURAL PRODUCTS

 

 

Date : 24-04-2012             Dept. No.                                        Max. : 100 Marks

Time : 9:00 – 12:00

Part-A

Answer ALL questions:                                                                                                 (10 ´ 2 = 20 Marks)

1. Compare the aromaticity of pyrrole, thiophene and furan.
2. How is a carbazole synthesized?
3. Mention the pharmacological activities of alkaloids.
4. What is Herzig Meyer method of estimation of alkaloids?
5. What are tannins? How are they different from flavonoids?
6. Define the following
7. a) isoprene rule b) gem-dialkyl rule
8. How is the presence of C-methyl group determined?
9. Give the Ziesel’s method of estimation of –OCH₃ groups in anthocyanins.
10. How is the position of double bond in zinziberene confirmed?
11. Give the mechanism for the following conversion.

 

 

 

 

Part-B

Answer any EIGHT questions:                                                                                       (8 ´ 5 = 40 Marks)

 

11. Nucleophilic substitution takes place readily on pyridine than benzene. Why?
12. Explain the reactivity of quinoline towards electrophilic substitution reaction.
13. What is the end product of Hoffmann degradation of N-methylpiperidine?
14. How is atropine synthesized?
15. Explain the following reactions.
16. a) Hoffmann exhaustive methylation reaction
17. b) Zerewitinoff reaction
18. Explain Baker Venkataraman synthesis of flavonoids.
19. Effect the conversion of 2-(1-naphthyl)ethylmagnesium bromide to Diels hydrocarbon.
20. Mention the use of the following reagents in the structural characterization of squalene.
21. a) Na/amyl alcohol    b) Ac₂O/1% H₂SO₄
22. Discuss the structural elucidation of cadinene.
23. Give the structure of gibberellic acid. How would you prove the presence of
    (i) lactone ring and      ii) two types of -OH groups in it?
24. Give the Robinson method of synthesis of hirsutidin chloride.
25. Elucidate the structure of pelargolidin chloride

 

Part-C

Answer any FOUR questions:                                                                                      (4 ´ 10 = 40 Marks)

 

23. a) Explain the electrophilic and nucleophilic substitution reactions in quinoline. (6)
24. b) How is thiophene synthesized from furan? (4)
25. a) Write the classification of alkaloids with examples. (5)
26. b) What are flavonoids? Mention their biological importance. (5)
27. Write the complete structural elucidation of Morphine. (10)
28. a) Effect the following conversions.                                                          (2 × 2.5)
29. i) camphoric acid to camphor
30. ii) cadinene to 2,7-dimethylcadalene
31. b) Identify A-E in the following.                                                                       (5)

 

 

 

 

 

 

27. Discuss the structural elucidation of zinziberene. (10)
28. a) Give the synthesis of oestrone from 3-(3-methoxyphenyl)-1-bromopropane. (5)
29. b) Discuss the structural elucidation of cyanidin chloride. (5)

 

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