The Vilsmeier-Haack reaction involves the reaction of substituted amides with phosphorus oxychloride and electron-rich arenes to produce aryl aldehydes or ketones. The document outlines the reaction mechanism, which includes the generation of the chloroiminium ion and the electrophilic attack on aromatic compounds. Applications of this reaction include the formylation of various compounds and the synthesis of heterocycles such as pyrroles and quinolines.

1. VILSMEIER-HAACK REACTION
Presented by Sukanta Debnath
M.Pharm 1st year
Presented to Dr. Pratap Ch. Acharya (Head of the Dept.)
Tripura University
Presentation on Advance Organic Chemistry -1

2. CONTENTS:-
• Introduction
• Reaction
• Mechanism
• Application
• References

3. Introduction:-
• The vilsmeier-haack reaction (also called vilsmeier
reaction) is the chemical reaction of substituted amide
with phosphorus oxychloride and electron rich arene to
produce aryl aldehyde or ketone.
• This reaction is named after Anton Vilsmeier and
Albrecht Haack.
• The reaction of a substituted amide with phosphorus
oxychloride gives a substituted chloroiminium ion also
called Vilsmeier Reagent

4. Reaction:-
O CH3
N H
CH3
O
+
O CH3
O
+
PoCl3
H2O
Anisole N –methyl
N-phenyl formamide 2-methoxybenzaldehyde
N
H
CH3
N-methylaniline
(Secondary aniline)

5. Mechanism:-
• Step:-1 (Generation of electrophile)
N H
CH3
O
+ P
Cl
Cl
Cl
O
N
+
CH3
H
O
P
Cl
Cl
O
+
Cl
–
N
C
+
CH3
H
Cl
+
P Cl
Cl
O
O
–
Chloroiminium ion

6. Mechanism :-
• Step:- 2 (Attack of electrophile)
O CH3
+
N
C
+
CH3
H
Cl
H
+
O
C
H3
N
CH3
Cl
H
O
+
C
H3
N
CH3
Cl
H
O
C
H3
H
H
N
+
CH3
Cl
–
O
H
H
O
H2
O
C
H3
N
CH3
H
O
H
O
C
H3
O
H
N
H
CH3

7. Applications:-
• Formylation of aromatic hydrocarbons,
phenols,ketones,phenolsethers.
• Synthesis of pyrroles.
• Synthesis of pyrimidines.
• Synthesis of pyrazoles.
• Synthesis of Quinolines and Indoles.

8. References:-
• Synthetic Strategies Towards Vilsmeier-Haack Reaction
• https://en.wikipedia.org/wiki/Vilsmeier%E2%80%93Haac
k_reaction
• Reddy, M. P.; Rao, G. S. K. J. Chem. Soc., Perkin Trans.
1 1981, 2662–2665.CrossRefGoogle Scholar