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

HRID 9118

Reaction equation

HRID 9118 reaction equation
F[B-](F)(F)F.[O:6]=[N+:7]=[O:8].[OH:9][C:10]1[C:18]2[S:17][C:16]([NH:19][C:20]([NH:22][CH2:23][CH3:24])=[O:21])=[N:15][C:14]=2[CH:13]=[CH:12][CH:11]=1>C(#N)C.C(OCC)C>[OH:9][C:10]1[C:18]2[S:17][C:16]([NH:19][C:20]([NH:22][CH2:23][CH3:24])=[O:21])=[N:15][C:14]=2[CH:13]=[CH:12][C:11]=1[N+:7]([O-:8])=[O:6]

Participants

5

Conditions

Temperature
20 °C

Procedure

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.

Workup

  1. customto get an orange solution
  2. stirringThe reaction mixture was stirred at about 20° C. for about 15 minutes
  3. washby washing with saturated sodium bicarbonate solution (1.5 mL)
  4. extractionThe organic extract
  5. concentrationwas concentrated
  6. dissolutiondissolved in methanol (2 mL)
  7. customLC/MS purification
  8. customwas followed by flash chromatography purification on silica (methylene chloride/methanol=40/1)

Sources & evidence

ORD record
ord-c336b764197e420a978d946859501796
Source dataset
uspto-grants-2006_08
Patent number
US07091227B2

Linked notes

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