Reaktion #48357

Reaktionsgleichung

3-[(1-Benzylpiperidin-4-yl)amino]pyrazine-2-carbohydrazide

sodium nitrite

sodium bicarbonate

→

title compound

2-Oxo-1-(1-benzylpiperidin-4-yl)-2,3-dihydro-1H-imidazo[4,5-b]pyrazine

Lösungsmittel

water

HCl

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionthe basic solution extracted with chloroform (5×50 mL), which
2. 2
   Trocknenwas dried over magnesium sulfate
3. 3
   workup.DISSOLUTIONThe crude acyl azide was dissolved in methoxyethanol (20 mL)
4. 4
   TemperaturThe reaction was cooled
5. 5
   Einengenconcentrated
6. 6
   Sonstigethe crude product purified by preparative thin layer chromatography (silica gel, 75:25 tetrahydrofuran:hexane)

Vorschrift

3-[(1-Benzylpiperidin-4-yl)amino]pyrazine-2-carbohydrazide (3.0 g, 9.2 mmol) was dissolved in 1N HCl (20 mL) and water (40 mL), and cooled to 0° C. To this was added aqueous sodium nitrite (0.8 g, 11.6 mmol) in water (5 mL). After 0.5 h sodium bicarbonate was added and the basic solution extracted with chloroform (5×50 mL), which was dried over magnesium sulfate. The crude acyl azide was dissolved in methoxyethanol (20 mL) and heated at 180° C. for 3 h. The progress of the reaction was monitored by thin layer chromatography (10% methanol in chloroform). The reaction was cooled and concentrated, and the crude product purified by preparative thin layer chromatography (silica gel, 75:25 tetrahydrofuran:hexane) to give the title compound (1.7 g). MS 310 (M+1).

Quelle