Dr. SK MOHAMMAD AZIZ - Narajole Raj College

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION

Dr. SK MOHAMMAD AZIZ

1

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION2

Molecular Rearrangements

Fries Rearrangement

Aryl esters with Lewis acid undergo rearrangement to give phenols having keto substituent at ortho and para positions. The complex between the ester and Lewis acid gives an acylium ion which reacts at the ortho and para positions as in Friedel-Crafts acylation.

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION3

Molecular Rearrangements

Mechanism Fries Rearrangement

In general, low temperature favors the formation of para-product (kinetic control) and high temperature lead to the formation ortho-product (thermodynamic control).

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION4

Molecular Rearrangements

Fries Rearrangement

Example:

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION5

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION6

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION7

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION8

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION9

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION10

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION11

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION12

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION13

Molecular Rearrangements

Hofmann-Martius Rearrangement

The Hofmann–Martius rearrangement in organic chemistry is a rearrangement reaction converting an N-alkylated aniline to the corresponding ortho and / or para aryl-alkylated aniline. The reaction requires heat, and the catalyst is an acid like hydrochloric acid.

The reaction is also known to work for aryl ethers and two conceptually related reactions are the Fries rearrangement and the Fischer–Hepp rearrangement. Its reaction mechanism centers around dissociation of the reactant with the positively charged organic residue R attacking the aniline ring in a Friedel–Crafts alkylation

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION14

Molecular Rearrangements

Mechanism:

Hofmann-Martius Rearrangement

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION15

Molecular Rearrangements

The conjugate acid of the amine releases nitrosonium ion which reacts at para-position to give the p-nitroso product.

This organic reaction was first described by the German chemist Otto Philipp Fischer and Eduard Hepp in 1886, and is of importance because para-NO secondary anilines cannot be prepared in a direct reaction. The rearrangement reaction takes place by reacting the nitrosamine precursor with hydrochloric acid. The chemical yield is generally good under these conditions, but often much poorer if a different acid is used.

The exact reaction mechanism is unknown but there is evidence suggesting an intramolecular reaction.

Fisher-Hepp Rearrangement

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION16

Molecular Rearrangements

Fisher-Hepp Rearrangement

Mechanism:

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION17

Molecular Rearrangements

N-azo to C-azo rearrangement

N-Arylazoanilines undergo rearrangement in presence of an acid to produce 4-(2- aryldiazenyl)aniline. On treatment with acid, aryldiazonium ion is formed from the conjugate acid of amine, which migrates to the para position almost selectively

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION18

Molecular Rearrangements

Bamberger rearrangement

Arylhydroxyamines with acid undergoes rearrangement to give aminophenols. Mechanism of this reaction is different from those described above. In this rearrangement, the conjugate acid of the hydroxylamine undergoes nucleophilic attack by the solvent.

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION19

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION20

Molecular Rearrangements

Orton rearrangement

Treatment of N-chloroacetanilide with hydrochloric acid affords a mixture of ortho and para-chloracetanilides in the same proportions as in the direct chlorination of acetanilide.

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION21

Molecular Rearrangements

Orton rearrangement

Mechanism:

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION22

Molecular Rearrangements

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION23

Molecular Rearrangements

Benzidine Rearrangement

These compounds undergo [5,5]-sigmatropic rearrangement in the presence of acid to give benzidines.

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION24

Molecular Rearrangements

Mechanism: Benzidine Rearrangement

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION25

Molecular Rearrangements

Home Task:

Predict the major products in the following reactions with mechanism

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION26

Molecular Rearrangements

What products would you expect from the following reactions? Explain with mechanisms

Home Task:

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION27

Molecular Rearrangements

Complete the following reactions with major products and mechanism

Home Task:

COMPILED AND CIRCULATED BY DR. SK MOHAMMAD AZIZ,

ASSISTANT PROFESSOR, DEPARTMENT OF CHEMISTRY, NARAJOLE RAJ COLLEGE

CHEMISTRY: SEM-IV, PAPER- C10T: ORGANIC CHEMISTRY-IV, REARRANGEMENT REACTION28

Molecular Rearrangements