2-Methyl-5-hydroxypyridine → 2-Bromo-6-methylpyridin-3-ol

Temperatur

70 °C

16.0 g (0.14 mol) of 3-hydroxy-6-methylpyridine are dissolved in 122 ml of 30% strength HBr in glacial acetic acid, and the solution is heated to 70° C. 70.4 [lacuna] (24.3 ml, 0.47 mol) of bromine are added dropwise at this temperature over a period of 1 hour. The reaction solution is stirred at this temperature for another 5 hours. After the reaction is complete, nitrogen is passed through the reaction solution for 2 hours (to drive off bromine). The reaction solution is then concentrated to 50 ml in vacuo. In this manner, an orange-red paste of the hydrobromide of the desired compound is obtained. The hydrobromide is boiled in 400 ml of water and then brought to a PH of 8 with a 1N bicarbonate solution. The dirty brown crude product obtained is recrystallized from water/methanol (2:3), giving colorless crystals of the pure product.

1. waitnitrogen is passed through the reaction solution for 2 hours
2. concentrationThe reaction solution is then concentrated to 50 ml in vacuo

ORD-Eintrag

ord-b92371dbf9ee46d48ea7773443ffca08

Quelldatensatz

uspto-grants-1993_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05266700