Acetic Acid → 2-Ethylamino-4-fluoro-5-nitro-phenol

HRID 1687987Notes

Reaction equation

HRID 1687987 reaction equation
[F:1][C:2]1[C:3]([N+:12]([O-:14])=[O:13])=[CH:4][C:5]2[O:9][C:8]([CH3:10])=[N:7][C:6]=2[CH:11]=1.C(O)(=O)C.[BH4-].[Na+].C(=O)(O)[O-].[Na+]>O1CCCC1>[CH2:8]([NH:7][C:6]1[CH:11]=[C:2]([F:1])[C:3]([N+:12]([O-:14])=[O:13])=[CH:4][C:5]=1[OH:9])[CH3:10]

Participants

6

Reactant 4

HCID 176Acetic AcidHCID 516892Sodium BicarbonateHCID 4311764Sodium borohydrideHCID 136277005-Fluoro-2-methyl-6-nitro-1,3-benzoxazole

Product 1

HCID 672636262-Ethylamino-4-fluoro-5-nitro-phenolYield 84.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

5-Fluoro-2-methyl-6-nitro-benzoxazole (2.556 g, 13.03 mmol) was dissolved in Tetrahydrofuran (90 mL) and Acetic acid (4.5 mL, 79 mmol). Sodium borohydride (1.48 g, 39.1 mmol) was added and the reaction was stirred at room temperature for 90 min, then poured into 100 mL satd. sodium bicarbonate. The solution was extracted 3×50 mL DCM and the combined organics were washed with 1:1 brine:satd. sodium bicarbonate (50 mL) and dried over sodium sulfate, then conc. onto 10 g Celite. The crude product was chromatographed (120 g silica gel, ISCO, 0-20-40% EtOAc:Hex) to afford 2-Ethylamino-4-fluoro-5-nitro-phenol as a yellow solid (2.20 g, 84%). 1H-NMR (CDCl3): 7.55 (d, 1H, J=6.8 Hz), 6.26 (d, 1H, J=13.2 Hz), 5.51 (s, 1H), 5.05 (s, 1H), 3.26 (m, 2H), 1.34 (t, 3H, J=6.8 Hz).

Workup

  1. additionpoured into 100 mL
  2. extractionThe solution was extracted 3×50 mL DCM
  3. washthe combined organics were washed with 1:1 brine
  4. dry with materialsodium bicarbonate (50 mL) and dried over sodium sulfate
  5. customThe crude product was chromatographed (120 g silica gel, ISCO, 0-20-40% EtOAc:Hex)

Sources & evidence

ORD record
ord-4d9d480b7d6447c2809efc90a44b8b41
Source dataset
uspto-grants-2012_04
Patent number
US08148391B2

Reaction notes

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