1. Advanced Pharmaceutical Analysis IR spectroscopy Examples
Lecture 3 17
Advanced Pharmaceutical Analysis IR spectroscopy Examples
P 105
Dr. Baraa Ramzi

3. Approach this as a puzzle - it can be fun!

4. Example 1
Ants emit tiny amounts of chemicals called alarm pheromones to warn other ants (of the same species) of the presence of an enemy. Several of the components of the pheromone in one species have been identified, and two of their structures follow. Which compound has the infrared spectrum shown?
Conjugation of CJO with phenyl; 1700—1660 cm−1

5. Example 1

6. Example 1

7. Example 2
The main constituent of cinnamon oil has the formula C9H8O. From the following infrared spectrum, deduce the structure of this component?

8. Index of Hydrogen Deficiency

9. Example 2 IHD=6 C9H8O Ar : above 3000 , 1600 , 700
Ald : c-h 2700 , 2800
C=o : , low wavenum cuz conj
C9H8O
IHD=6

10. Example 3 B

11. Example 4 E

12. Example 5 D

13. Example 6 C

14. Example 7
Assign a structure to each of the following three spectra. The structures are shown here.

15. Example 7
(1)

16. Example 7
(2)

17. Example 7
(3)

18. Example 8
Choose the structure that best fits the infrared spectrum shown

19. Example 8

20. Example 8

21. Example 9
In each of the following parts, a molecular formula is given. Deduce the structure that is consistent with the infrared spectrum.

22. Example 9
Strong band N-H when attached to aromatic
IHD=4

23. Example 10
C3H6O2
IHD=1

24. Example 11
Choose the structure that best fits the infrared spectrum shown

25. Example 11

26. Example 11

27. Example 12
C7H6O2
IHD=5

28. Example 13
Choose the structure that best fits the infrared spectrum shown

29. Example 13

30. Example 13

31. Di-methyl Gem
Doublet at and

32. Di-methyl Gem

33. Example 14
C7H6O
IHD=5