Reaktion #367926

Reaktionsgleichung

sodium carbonate

hypophosphorous acid

charcoal

2-guanidino-4-(2-amino- 4-imidazoyl)thiazole dihydrochloride

sodium nitrate

sulfuric acid

→

2-guanidino-4-(4-imidazoyl)thiazole

Ausbeute 5.0%

Lösungsmittel

methanol

water

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturwas cooled to -10°
2. 2
   workup.STIRRINGstirring
3. 3
   workup.STIRRINGThe reaction was stirred at 50° for 2 hours
4. 4
   workup.WAITat room temperature for 16 hours
5. 5
   Extraktionextracted three times with 150 ml portions of ethyl acetate
6. 6
   TrocknenThe combined ethyl acetate extracts were dried over sodium sulfate
7. 7
   Filtrationfiltered
8. 8
   Sonstigeevaporated
9. 9
   Sonstigeleaving a solid
10. 10
    Einengenconcentrated to a small volume
11. 11
    SonstigeThe resulting solid was collected
12. 12
    Sonstigedried

Vorschrift

A mixture of 42 ml of concentrated sulfuric acid and 21 ml of water was cooled to -10° and 1.56 g (22.7 mmol) of sodium nitrate was added. Afrer stirring at -5° for ten minutes, 8.1 ml (78 mmol) of cold 50% hypophosphorous acid was added and stirring was continued for another 10 minutes at -5°. A solution of 2.5 g (8.4 mmol) of 2-guanidino-4-(2-amino- 4-imidazoyl)thiazole dihydrochloride in 100 ml of water was added dropwise over 0.5 hour. The reaction was stirred at 50° for 2 hours, then at room temperature for 16 hours. The reaction mixture was diluted with 500 ml of water, made basic with solid sodium carbonate and extracted three times with 150 ml portions of ethyl acetate. The combined ethyl acetate extracts were dried over sodium sulfate, filtered, and evaporated leaving a solid. This solid was taken up into boiling methanol, decolorized with charcoal, and concentrated to a small volume. The resulting solid was collected and dried, thereby affording 90 mg (5%) of 2-guanidino-4-(4-imidazoyl)thiazole identical to the material of Example 31 by thin layer chromatography and high resolution mass spectrometry.

Quelle