Unit-I: Non-Aromatic Heterocyclic Compounds. Section-A: Each question carries 5 Marks: 1. Explain the ring opening reactions of azirines. 2. Explain Neber Rearrangement. 3. Explain the term strain with respect to azirine&aziridine. 4. Describe two methods for the generation of oxiranes. 5. Explain two ring opening reactions of thiirane. 6. How do you convert methyl oxirane to methyl thiirane. 7. Explain different types of strains. 8. Explain the structural factors affecting conformations of flexible heterocyclics. 9. Explain the synthesis of Azirines from the following: i. Vinyl azides ii. Isoxazoles. 10. Explain the synthesis of Aziridine from following: i. Gabriel method ii. Wenker method 11. Explain Hassner method to synthesise Aziridine. 12. Explain the ring opening reactions of aziridines. 13. Explain the ring opening reactions of oxiranes. 14. Explain the synthesis of thiiranes. 15. Explain any two synthesis of thiranes from oxiranes 16. Write any two synthesis of Diazirines. 17. Explain the reactivity of Diazirines. 18. Explain the synthesis of Diaziridines. 19. Explain the reactivity of diaziridines. 18. Explain the synthesis of Oxaziridines. 19. Explain the reactivity of Oxaziridines. 20. Explain the synthesis of Azetidines. 21. Explain the synthesis of azetidines from aziridines. 22. Explain ring opening reactions of Azetidines. 23. Explain the synthesis of Oxetanes 21. Explain the synthesis of Oxetanes from oxiranes. 22. Explain ring opening reactions of Oxetanes. 23. Explain the synthesis of thietanes. 21. Explain the synthesis of thietanes from thiiranes&Oxiranes. 22. Explain the ring opening reactions of thietanes. 24. Complete the Following reactions. 25. Complete the Following reactions. 26. Complete the Following reactions. 27. Complete the Following reactions. 28. Complete the Following reactions. 29. Complete the Following reactions. Section-B: Each question carries 10 Marks: 1. a. Predict the products in the following reactions. b. Write the synthesis and reactivity of thiiranes. 2. a. Explain the ring opening reactions of oxetanes. b. Write the major product in the following reaction. 3. a. Explain the two ring opening reactions of Azirine&Diazirine. b. Give the synthesis & reactivity of Oxetanes. 4. a. Give a method for synthesis of the following: i. Thietane ii. Azetidine. b. Explain the ring opening reactions of the following: i. Thietane ii. Oxaziridine 5. a. Give a method for the synthesis of diaziridine&oxaziridine from a common ketone. b. Explain a method of synthesis for each of the following: i. Oxaziridine ii. Oxiranes. 6. a. Predict the products in the following: b. Explain the ring opening reactions of Azirines. 7. a. Explain different types of strains & interactions. b. Explain the conformational aspects of non-aromatic heterocyclics . 8. a. Write the synthesis of Azirine&Aziridines. b. Write about the ring opening reactions of Aziridines. 9. a. Explain the synthesis of aziridine by the following methods. i. Gabriel Method ii. Cycloaddition. b. Explain Neber rearrangement to prepare Azirine. 10.a. Complete the following reactions by predicting the products b. Write any one synthesis of Oxirane, thiiranes&aziridine. 11.a. Explain Electrophilic &Nucleophilic Ring opening reactions of Oxiranes. b. Write two synthesis of thiiranes from oxiranes. 12. a. Explain Desulphurization & photochemical reactions of Thiiranes. b. Explain the formation of the following products: 13. a. Explain the reactivity of Diaziridines. b. Explain thermal & photochemical rearrangement reactions of Oxaziridines. 14. a. Explain the synthesis of Azetidines from following: i. isoxazolines ii. γ-lactones b. Explain the reactivity of azetidines. 15. a. Explain the synthesis of Oxetanes from Paternobuchii reaction. b. Explain the synthesis of thietanes from oxiranes&thiiranes. 16. a. Explain the synthesis of thietanes from following: i. 1, 3- dihalo alkanes ii. Cyclic carbonates. b. Explain the ring opening reactions of Oxetanes. 17. a. Explain the formation of the Products: b. Explain the reactivity of Thietanes. UNIT-2: FIVE AND SIX MEMBERED HETEROCYCLES WITH TWO HETERO ATOMS SECTION –A (Each question carries 5 marks) 1. Describe the aromatic character of azoles? 2. Give the synthesis of barbutiric acid? 3. Imidazole is tautomeric explain? 4. Outline the synthesis of pyridazine 5. Give any one synthesis of pyrazole ring? 6. Write the products formed when nitro benzene reacts with 1,3butadiene? 7. Outline one method of the synthesis of imidazole and isothiazole? 8. Outline the synthesis of pyrazole? 9. Outline the synthesis of thiazole? 10. Outline the synthesis of oxazole? 11. Outline the synthesis of isoxazole? 12. Outline the synthesis of pyridazine? 13. Outline the synthesis of pyrimidine? 14. Outline the synthesis of pyrazine? 15. Outline the synthesis of oxazine? 16. Outline the synthesis of thiazine? 17. Explain the reactivity of imidazoles? 18. Explain the reactivity of thiazoles? 19. Explain the reactivity of pyrazoles? 20. Explain the reactivity of isothiazoles? 21. Explain the reactivity of oxazoles? 22. Explain the reactivity of isoxazoles? 23. Explain the reactivity of pyrazines? 24. Explain the reactivity of oxazines? 25. Explain the reactivity of thiazines? 26. Explain the reactivity of pyridazines? 27. Explain the reactivity of pyrimidines? SECTION –B (Each question carries 10 marks) 1. a. Outline the importance and reactivity of pyrimidines? b. Outline synthesis and reactivity of isoxazole 2. a. Outline one method of synthesis of pyrazine, isothiazole and thiazine? b. Outline synthesis and reactivity of imidazole? 3. a. Outline the importance and reactivity of pyrazines? b. Outline synthesis and reactivity of isothiazole? 4. a. Outline the importance and reactivity of pyridazines? b. Outline synthesis and reactivity of pyrazole? 5. a. Outline the importance and reactivity of oxazole? b. Outline synthesis and reactivity of thiazole? 6.a. Outline the importance and reactivity of pyrimidines? b. Outline synthesis and reactivity of oxazole? 7. a. Outline the importance and reactivity of thiazine? b. Outline synthesis and reactivity of pyrazines? 8. a. Outline synthesis and reactivity of pyrimidines? b. Outline the reactivity of isothiazole? 9. a. Explain a method each for the synthesis of thiazoles and oxazoles from α-halo ketones? b. Write the products in the following reactions. Explain their mechanism? 10. a. Describe the aromatic of 1, 3 azoles and 1, 2 azoles? b. Explain the aromatic character and reactivity of imidazole. 11. a. Describe the synthesis and reactivity of pyrazole? b. Give the synthesis of the following compounds 1. Thiazoles 2. Pyrimidines UNIT-3: HETEROCYCLES WITH MORE THAN TWO HETERO ATOMS SECTION –A (Each question carries 5 marks) 1. 1. Outline synthesis of 1,2,3-triazoles? 2. 2. What is a sydnone? Write any one synthesis of sydnone? 3. 3. Describe the synthesis of purine ring system from a pyrimidines 4. 4. Write the structure of any 2 purine bases and outline their synthesis? 5. 5. Describe the synthesis of 1,3,4-oxadiazoles and 1,3,4 thiadiazoles? 6. 6. Write the structures of caffeine, theobromine and theophylline? 7. 7. Outline synthesis of 1,2,4-triazoles? 8. 8. Outline synthesis of Tetrazoles? 9. 9. Outline synthesis of 1,2,4-oxadiazoles? 10. 10. Outline synthesis of 1,3,4-oxadiazoles? 11. 11. Outline synthesis of 1,2,5-oxadiazoles? 12. 12. Outline synthesis of 1,2,4-thiadiazoles? 13. 13. Outline synthesis of 1,2,3-thiadiazoles? 14. 14. Outline synthesis of 1,3,4-thiadiazoles? 15. 15. Outline synthesis of 1,2,5-thiadiazoles? 16. 16. Outline synthesis of 1,2,3-triazines? 17. 17. Outline synthesis of 1,2,4-triazines? 18. 18. Outline synthesis of 1,3,5-triazines? 19. 19. Outline synthesis of tetrazines? 20. 20. Explain the synthesis and importance of purines? 21. 21. Explain the synthesis and importance of pteridines. 22. 22. Outline synthesis of Caffeine, theobromine and theophylline? 23. 23. Explain the aromatic character of triazoles? 24. 24. Explain the aromatic character of tetrazoles? 25. 25. Explain the aromatic character of oxadiazoles? 26. 26. Explain the aromatic character of thiadiazoles? 27. 27. Explain the aromatic character of triazines? 28. 28. Outline the reactivity of 1,2,3-triazoles? 29. 29. Outline the reactivity of 1,2,4-triazoles? 30. 30. Outline the reactivity of Tetrazoles? 31. 31. Outline the reactivity of 1,2,4-oxadiazoles? 32. 32. Outline the reactivity of 1,3,4-oxadiazoles? 33. 33. Outline the reactivity of 1,2,5-oxadiazoles? 34. 34. Outline the reactivity of 1,2,4-thiadiazoles? 35. 35. Outline the reactivity of 1,2,3-thiadiazoles? 36. 36. Outline the reactivity of 1,3,4-thiadiazoles? 37. 37. Outline the reactivity of 1,2,5-thiadiazoles? 38. 38. Outline the reactivity of 1,2,3-triazines? 39. 39. Outline the reactivity of 1,2,4-triazines? 40. 40. Outline the reactivity of 1,3,5-triazines? 41. 41. Outline the reactivity of tetrazines? SECTION –B (Each question carries 10 marks) 1. a. Outline the importance and reactivity of 1,2,3-triazoles? b. Outline synthesis and reactivity of 1,2,3-triazine? 2. a. Outline one method of synthesis of 1, 2, 4-triazoles, Tetrazoles, 1, 2, 4- oxadiazole? b. Outline synthesis Caffeine, theobromine and theophylline? 3. a. Outline the importance and reactivity of 1,3,4-thiadiazoles? b. Outline synthesis and reactivity of 1,3,5-triazines? 4. a. Outline the importance and reactivity of 1,2,5-oxadiazoles? b. Outline synthesis and reactivity of tetrazines? 5. a. Outline the importance and reactivity of 1,3,4-oxadiazoles? b. Outline synthesis and reactivity of 1,2,4triazines? 6. a. Outline the importance and reactivity of 1,2,4-oxadiazole ? b. Outline synthesis and reactivity of Tetrazoles? 7. a. Outline the importance and synthesis of purines? b. Outline synthesis and reactivity of 1,2,4triazines? 8. a. Outline synthesis and importance of pteridines? b. Outline the synthesis and reactivity of 1,2,5- thiadiazoles ? 9. a. Outline synthesis and importance of 1,2,4- thiadiazoles? b. Outline the synthesis and reactivity of 1,2,3- thiadiazoles ? 10.