WOODWARD-FEISER RULE detailed information

WOODWARD-FEISER RULE detailed information

1. A SEMINAR
ON
WOODWARD -FEISER RULE
PRESENTED BY:
NIVEDITHA G
1
st
sem Mpharm
Dept of pharmaceutics
NARGUND COLLEGE OF PHARMACY
1

2. Woodward(1941) : gave certain rules for correlating 
max
with molecular structure.
Scott-Feiser(1959): modified rule with more experimental
data, the modified rule is known as Woodward-Feiser rule.
used to calculate the position of 
maxfor a given structure
by relating the position and degree of substitution of
chromophore.
2

3. 1.Homoannular diene:cyclic diene having conjugated
double bonds in the same ring.
2. Heteroannular diene:cyclic diene having
conjugated double bonds in different ring
3

4. 3.Endocyclic double bond:double bond present in a
ring
4.Exocyclic double bond:double bond in which one of
the doubly bonded atoms is a part of a ring system
Ring ARing B
Ring A has one exocyclic and endocyclic double
bond. Ring B has only one endocyclic double bond
4

5. Woodward-Feiser rulefor conjugated dienes,
triens, polyenes:
Each type of diene or triene system is having a
certain fixed value at which absorption takes place;
this constitutes the BASIC VALUEor PARENT
VALUE
The contribution made by various alkyl substituents
or ring residue,double bonds extending conjugation
and polar groups such as –Cl, -Br are added to the
basic value to obtain 
maxfor a particular compound
5

6. Parent values and incriments for different
substituent/groups:
(a) Parent value:
i. Acyclic conjugated diene and
heteroannular conjugated diene : 215nm
ii. Homoannular conjugated diene : 253nm
iii. Acyclic triene : 245nm
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7. b)Increments:
i.Each alkyl substituents or ring residue : 5 nm
ii.Exocyclic double bond : 5 nm
iii.Double bonds extending conjugation : 30 nm
c)Auxochrome:-OR : 6 nm
-SR : 30 nm
-Cl, -Br : 5 nm
-NR
2 : 60 nm
-OCOCH
3 : 0 nm
7

8. Calculate
maxfor 1,4-dimethylcyclohex-1,3-diene
H
3C CH
3 H3C CH3
Parent value for homoannular ring : 253 nm
Two alkyl substituents : 2 * 5 = 10nm
Two ring residue : 2 * 5 = 10 nm
calculated value 273 nm
Observed value 263 nm
8

9. Calculate
max
Parent value for heteroannular diene : 215 nm
Four ring residue : 4 *5 =20 nm
calculated value 235 nm
observed value 236 nm
9

10. Calculate 
max
Parent value for heteroannular diene : 215 nm
Three ring residue :3 * 5 =15 nm
One exocyclic double bond : 5 nm
Calculated value 235 nm
Observed value 235 nm
10

11. Woodward-Feiser Rules for ,-unsaturated
carbonyl compounds
a) Parent values
i. ,-unsaturated acyclic or six membered ring : 215 nm
ketone
ii. ,-unsaturated five –membered ring ketone : 202 nm
iii. ,-unsaturated aldehyde : 207 nm
b) Increments
i.Each alkyl substituent or ring residue
at position : 10 nm
at position : 12 nm
at position : 18 nm
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12. ii.Each exocyclic double bond : 5 nm
iii.Double bond extending conjugation : 30 nm
iv. Homoannular conjugated diene : 39 nm
c) Auxochromes position
  
-OH 35 30 50
-OR 35 30 17
-SR - 85 -
-OCOCH3 6 6 6
-Cl 15 12 -
-NR2 - 95 -
12

13. Parent value for ,-unsaturated 6
membered cyclic ketone : 215 nm
One ring residue at position : 10nm
Two ring residue at position : 2* 12=24 nm
Double bond exocyclic to two ring : 2* 5 =10nm
calculated value 259nm
observed value 256nm
CALCULATE max:
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14. CALCULATE 
max: βα
Parent value : 215 nm
One αring residue : 10nm
One δresidue : 18nm
One double bond extending : 30nm
conjugation
•One homoannular conjugated diene : 39nm
•One exocyclic double bond : 5nm
Calculated value 317nm
Observed value 319nm
14

15. REFERENCE
INSTRUMENTAL METHOD OF CHEMICAL
ANALYSIS by GURUDEEP R. CHATWAL, SHAM.
K. ANAND5
th
edition, Page no. 2.162-7.
INTERNET SOURCES.
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