WOODWARD FIESER RULE PDF
5 Nov woodward fieser rule. 1. Presented by: cy 1st yr Department of pharmaceutical analysis; 2. Introduction. WOODWARD-. 5 May Brief description of Woodward Fieser Rules. * Examples for all te 3 rules. Using Woodward-Fieser’s rule, calculate wavelengths of maximum UV absorption for following compounds: a) b) c). Base value: nm. Base value: nm.
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This page was last edited on 1 Juneat Pritt Balagopal 5, 2 14 Inputs used in the calculation are the type of chromophores present, the substituents on the chromophores, and shifts due to the solvent.
Sign up or log in Sign up using Google. Fieser; Mary Fieser; Srinivasa Rajagopalan Should the marked fiewer bond considered as an exocyclic double bond?
Central Connecticut State University. For example, in this compound, should the marked double bond considered as an exocyclic double bond? If we start with the alkene at the bottom left, then it is in conjugation with an endocyclic alkene to the immediate right and an exocyclic alkene in the ring to the right hand side. Questions Tags Users Badges Unanswered.
Woodward’s rules – Wikipedia
From Wikipedia, the free encyclopedia. For polyenes having more than 4 conjugated double bonds one must use Fieser—Kuhn rules.
So, the pointed double bond is exocyclic to the adjoining cyclopentane ring. Sign up using Email and Password. With the aid of these rules the UV absorption maximum can be predicted, for example in these two compounds: In the compound on the right, the diene is homoannular with 4 alkyl substituents.
What I want to know is whether fiesser double bond must be a part of the conjugated system for it to be considered as an exocyclic double bond in the calculation? But according to the paper by Fieser the pointed double bond is exocyclic to the 5 membered ring or right.
If you try this for your molecule you’ll quickly see that the bond you’ve highlighted is too distant from the conjugated system to have any involvement.
Physical organic chemistry Spectroscopy. These double bonds are all in conjugation with one another. If you fiesfr a double bond outside a ring as in the 4 ring system hereit will be considered as exocyclic. VirtualText of Organic Chemistry. Khurram Javed 1 1.
Thanks for the answer. Post as a guest Name. Alkyl substituent or ring residue.
Retrieved from ” https: Both double bonds in the central B ring are exocyclic with respect to rings A and C. When looking for exocyclic double bonds in a diene, should a double bond not connected to the conjugated system be considered?
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Sign up using Facebook. A diene is either homoannular with both double bonds contained in one ring or heteroannular with two double bonds distributed between two rings. The bond you’ve pointed at isn’t in conjugation with the ‘triene’ The Woodward rules are specifically related to the effect of groups in conjugationa simple test of which is to see if you can push curly arrows between the pi bonds.