Reaktion #49979

Reaktionsgleichung

nitronium tetrafluoroborate

2-amino-4-trimethylsilyl-6-trifluoromethoxybenzothiazole

→

2-amino-4-nitro-6-trifluoromethoxybenzothiazole

Ausbeute 43.3%

Lösungsmittel

water

acetonitrile

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeclose to 20° C
2. 2
   Extraktionextracted with 2 times 50 cm3 of ethyl acetate
3. 3
   Trocknendried over sodium sulphate
4. 4
   Einengenconcentrated in vacuum
5. 5
   SonstigeThe residue is purified by flash chromatography on silica gel with a cyclohexane-ethyl acetate mixture (7-3 by volume) as eluent
6. 6
   SonstigeAfter recrystallization from a cyclohexane-ethyl acetate mixture (3-2 by volume)

Vorschrift

0.68 g of nitronium tetrafluoroborate are added in small portions to a solution of 0.76 g of 2-amino-4-trimethylsilyl-6-trifluoromethoxybenzothiazole in 20 cm3 of acetonitrile cooled to 0° C. Stirring is continued for 12 hours at a temperature close to 20° C. The solution is then diluted with 50 cm3 of water and extracted with 2 times 50 cm3 of ethyl acetate. The organic phases are combined, dried over sodium sulphate and concentrated in vacuum. The residue is purified by flash chromatography on silica gel with a cyclohexane-ethyl acetate mixture (7-3 by volume) as eluent. After recrystallization from a cyclohexane-ethyl acetate mixture (3-2 by volume), 0.3 g of 2-amino-4-nitro-6-trifluoromethoxybenzothiazole melting at 260° C. is obtained.

Quelle