Reaktion #65930

Reaktionsgleichung

calcium carbonate

sodium nitrite

3-Dipropylamino-5-aminochroman

trifluoracetic acid

Sodium nitrite

→

title compound

3-Dipropylamino-5-nitrochroman

Lösungsmittel

water

water

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe clear solution was cooled to 0°-4° C
2. 2
   workup.STIRRINGThe solution was stirred at 0° C. for 20 minutes
3. 3
   workup.WAITat ambient temperature for 2 hours
4. 4
   ExtraktionThe solution was extracted with diethyl ether
5. 5
   TrocknenThe organic phase was dried with sodium sulfate
6. 6
   Sonstigeevaporated to dryness
7. 7
   SonstigeThe residue was purified by flash chromatography on silica gel by elution with ethyl acetate/hexane 1:9

Vorschrift

3-Dipropylamino-5-aminochroman (Example 14; 0.050 g, 0.20 mmol) was dissolved in a mixture of trifluoracetic acid (0.080 ml, 1.0 mmol) in water (5 ml). The clear solution was cooled to 0°-4° C. Sodium nitrite (0.017 g, 2.5 mmol) in water (1.0 ml), was added dropwise with good stirring. The solution was stirred for 15 minutes and neutralized with calcium carbonate. A solution of sodium nitrite (0.50 g, 7.2 mmol) in water (1.0 ml) was added followed by a mixture of copper sulfate (0.10 g, 0.62 mmol) and copper (1) oxide in water (1.0 ml). The solution was stirred at 0° C. for 20 minutes and then at ambient temperature for 2 hours. The solution was extracted with diethyl ether. The organic phase was dried with sodium sulfate and evaporated to dryness. The residue was purified by flash chromatography on silica gel by elution with ethyl acetate/hexane 1:9 to give the title compound. Mp 150°-151° C. (hydrochloride).

Quelle