Page 38 - Org 3 theoritical book 2024-25

Clinical Pharmacy PharmD - 2024/2025 Level 2 Pharmaceutical Organic Chemistry-3 (PC 305)

2. Formylation of pyrrole is carried out using Gattermann reaction or

much better by using the Vilsmeier reaction.

Pyrrole-2-carboxaldehyde differs from aromatic aldehydes in giving negative

reactions with the Schiff’s, Tollen’s, Cannizzaro, benzoin and Perkin’s reactions.

3. Reduction of pyrrole

The reduction of pyrrole is difficult due to its aromatic nature. With zinc dust and

acetic acid pyrrole gives 2,5-dihydropyrrole, while catalytic reduction leads to the

formation of the fully hydrogenated compound, tetrahydropyrrole (Pyrrolidine).

Zn/HOAc H /Ni
2
N N N
H H H
2,5-dihydropyrrole tetrahydropyrrole
(3-pyrroline) (pyrrolidine)

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