Reaktion #9214

Reaktionsgleichung

1-(7-hydroxy-2-benzothiazolyl)-3-ethyl-urea

1-(7-Hydroxy-2-benzothiazolyl)-3-ethyl-urea

nitronium tetrafluoroborate

→

desired compound 17

Ausbeute 10.4%

1-(7-Hydroxy-6-nitro-2-benzothiazolyl)-3-ethyl-urea

Ausbeute 10.4%

Lösungsmittel

acetonitrile

diethyl ether

acetonitrile

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeto get an orange solution
2. 2
   workup.STIRRINGThe reaction mixture was stirred at about 20° C. for about 15 minutes
3. 3
   Waschenby washing with saturated sodium bicarbonate solution (1.5 mL)
4. 4
   ExtraktionThe organic extract
5. 5
   Einengenwas concentrated
6. 6
   workup.DISSOLUTIONdissolved in methanol (2 mL)
7. 7
   SonstigeLC/MS purification
8. 8
   Sonstigewas followed by flash chromatography purification on silica (methylene chloride/methanol=40/1)

Vorschrift

To a solution of 2-methylpyridone (0.020 mL, 0.20 mmol, 1.2 eq) in anhydrous acetonitrile (0.5 mL), nitronium tetrafluoroborate (0.045 g, 0.32 mmol, 1.9 eq) was added. The suspension was stirred at about 20° C. for about 5 minutes to get an orange solution. The solution was then transferred to a suspension of 1-(7-hydroxy-2-benzothiazolyl)-3-ethyl-urea 8 (0.040 g, 0.17 mmol) in acetonitrile (0.5 mL). The reaction mixture was stirred at about 20° C. for about 15 minutes, then taken up in diethyl ether (8 mL), and neutralized by washing with saturated sodium bicarbonate solution (1.5 mL). The organic extract was concentrated and dissolved in methanol (2 mL). LC/MS purification was followed by flash chromatography purification on silica (methylene chloride/methanol=40/1) to afford 0.005 g (10%) of the desired compound 17. 1H NMR (DMSO) δ 11.20 (br s, 1H, NH), 8.02 (d, 1H, J=9.0 Hz, ArH), 7.23 (d, 1H, J=7.5 Hz, ArH), 6.78 (br s, 1H, NH), 3.20 (m, 2H, CH2), 1.10 (t, 3H, J=7.2 Hz, CH3). LC/MS 283 (MH+); RP-HPLC RT 2.74 minutes.

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