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In the Reimmer-Timmer reaction cho group is added to only at ortho position not at para position , I got the answer for this as ortho effect . So what is exactly ortho effect.

In the Reimmer-Timmer reaction cho group is added to only at ortho position not at para position , I got the answer for this as ortho effect. So what is exactly ortho effect.

Grade:11

2 Answers

Jayant Kishore
144 Points
8 years ago
First of all , in  Reimmer-Timmer reaction both ortho and para derivatives are formed , but the ortho derivative  is the major product because the intramolecular H-bonding in salicylaldehyde (ie. ortho derivative) results in the formation of a six member ring (which is also known as chelate ring). This has no relation to the ortho effect.
Ortho effect is applicable to benzoic acids and anilines and all their meta or para derivatives.Ortho substituted benzoic acids and anilines are more acidic than benzoic acid and aniline respectively. This is due to the fact that due to steric hinderance -COOH or -NH2 group does not remain planar with the benzene ring .Hence , all resonance effects will be ineffective. 
I think you need to brush up your concepts of H-bonding as it plays an important role especially in organic chemistry for checking stability of molecules.
 
: JAYANT 
 
NARAYANA
242 Points
8 years ago
ORTHO EFFECT IS APPLICABLE TO BENZOIC ACIDS AND ANILINES.IT STATES THAT ORTHO SUBSTITUTED BENZOIC ACID AND ANILINES ARE MORE

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