1. Rayat Shikshan sanstha’s S.M. Joshi College, Hadapsar, Pune.
Chemistry Department
Reactions And Mechanism
MSc
Monika D. shelake
Department of Chemistry
S.M.Joshi college

2. Rearrangement
Migration of atom or group of atoms from one atom to another
is referred to as rearrangement. 1

3. The main points regarding the rearrangement
Migrating group may leave the molecule during migration but subsequently it gets re-attached at some other reactive site of the molecule.
Sometimes migrating group never leaves the molecule during migration (intra-molecular rearrangement).
The rearrangement involves migration of an atom or group from one atom to an adjacent atom i.e. 1,2-shift (migration of C, H) along with X, O, S, N, R or Ar group
A group may migrate to an electron deficient C, N, O, or to an electron rich C. 2

4. Schmidt Reaction
Carboxylic acids and hydrazoic acid reacts in presence of H2SO4 to give amine, the reaction is called as Schmidt reaction. 3

5. The Reaction
Free hydrazoic acid is highly toxic and hence Na-azide is slowly added to the solution of carboxylic acid in H2SO4, when hydrazoic acid is liberated.
Reaction also occurs with ketones and aldehydes.
Ketone gives substituted amides.
Aldehyde gives mixture of nitriles and N-formyl derivatives. 4

6. Mechanism 5

7. Aldehydes and ketones on treatment with H-N3 & conc
Aldehydes and ketones on treatment with H-N3 & conc. H2SO4 gives nitriles and N-formyl derivatives and substituted amides. 6

8. From ketones
If ‘R’ group is migrated; 7

9. From aldehyde
If ‘R’ group migrated;

10. If ‘H’ is migrated

11. Features
Electron donating substituents increases the rate of reaction.
It is intramolecular in nature.
For the preparation of substituted amide from ketone.
There is retention in configuration takes place at the migrating group.
If excess amount of H-N3 is used we get substituted tetrazone. 10

12. Eg. 11

13. Applications
For the preparation of amines from acids: 12

14. assignment For the preparation of substituted amide from ketone.
Eg. From Ph-CO-CH3 to Ph-NHCOCH3
For preparation of N-formyl derivatives from aldehydes.
Eg. From Ph-CHO to Ph-NHCHO 14

15. For the preparation of nitrile:
From the above practice; 14

16. Preparation of lactums
Cyclic ketones gives lactums.
Cyclopentanone gives e-caprolactum 15

17. Mechanism 16

18. Thank you

19. Anode is where oxidation takes place
An Ox
Losing Electrons is Oxidation

20. Red Cat Cathode is where reduction takes place
Gaining Electrons is Reduction

21. Positively charged ion
Cation

22. Anion
a negatively charged ion