1. UV Spectroscopy problems Y. B. Chavan College of Pharmacy
K G Baheti
Y. B. Chavan College of Pharmacy
Aurangabad

2. Woodward Fieser Rule for diene:
Dienes are compounds containing two double bond in open chain or cyclic form.
Base value for Homoannular diene 253nm
Base value for Heteroannular diene 214nm

3. Homoannular diene Cisoid
Heteroannular diene transoid
Double bond present in same ring
Double bond present in different ring
Ring residue:
Part of carbocyclic ring directly lined to diene
Exocyclic double bond:
Double bond to the ring structure

4. Ring residue
Exocyclic double bond

5. Problems:
1. How many exocyclic double bond? What is their value in nm?
2. Calculate the λ max value for diene?

6. Q. Calculate the λ max value for diene?
Base value for heteroannular diene 214nm
Increment for 4 ring residue 20nm
234nm

7. Woodward Fieser Rule for enones :

9. Examples:
Calculate the λmax for the compound?

11. Rules for a,b-unsaturated aldehydes, acids and esters:

14. Rules for Benzoyl derivatives:

15. Calculate the λmax for the compound?

16. YES =244 nm =227nm
2 ring residue + 1 exocyclic double bond
YES nm =256nm
Base value for benzoyl deri 246nm

17. = 249
1-alpha sub, 2-beta sub.

21. Question Bank:
Q. Discuss the theory of Uv Visible spectroscopy?
Q. Discuss in detail instrumentation of UV visible spectrometer.
Q. Discuss the Uv spectrophotometric methods.
Q. Discuss the chemical derivitazation in Uv visble spectroscopy.
Q. Determine the λmax for the compounds.
Q. Solve the following problems.
Q. Write a short note on:
Beer lambert’s law
Woodward fieser rule
Simultaneous method development
Derivative spectroscopy