Réaction #1869164

Équation de réaction

2-Amino-5-bromopyridine

2,5-hexanedione

p-toluenesulfonic acid

→

5-Bromo-2-(2,5-dimethylpyrrol-1-yl)pyridine

Rendement 80.0%

Solvants

heptane

Conditions de réaction

Traitement

1. 1
   Températurerefluxed under Dean Stark conditions overnight
2. 2
   workup.DISTILLATIONThe equipment was set for distillation and heptane (18 L)
3. 3
   Autrewas removed by distillation
4. 4
   workup.ADDITIONSeed crystals were added
5. 5
   Autreat 5° C.
6. 6
   Autreovernight
7. 7
   FiltrationThe product was collected by filtration
8. 8
   Lavagewashed with heptane (2×6 L)
9. 9
   Autredried at 45° C. under vacuum overnight

Mode opératoire

2-Amino-5-bromopyridine (6.0 Kg, 34.7 mol), 2,5-hexanedione (4.35 Kg, 38.2 mol) and p-toluenesulfonic acid (12 g) were dissolved in heptane (36 L) and refluxed under Dean Stark conditions overnight. The equipment was set for distillation and heptane (18 L) was removed by distillation. The mixture was cooled to 20° C. for 60 minutes. Seed crystals were added and the mixture granulated at 20° C. for 2 hours and then at 5° C. overnight. The product was collected by filtration, washed with heptane (2×6 L) and dried at 45° C. under vacuum overnight. Yield=80% (7.0 Kg) δH (CDCl3 300 MHz) 2.20 (6H, s), 5.95 (2H, s), 7.15 (1H, d), 7.95 (1H, d), 8.70 (1H, s) ppm. MS m/z 253 (MH+, Br isotope).

Source