4-Nitro-2-(trifluoromethyl)-1,3-benzoxazole → 2-(Trifluoromethyl)-4-benzoxazolamine

HRID 2378430Notes

Reaction equation

HRID 2378430 reaction equation
[N+:1]([C:4]1[C:9]2[N:10]=[C:11]([C:13]([F:16])([F:15])[F:14])[O:12][C:8]=2[CH:7]=[CH:6][CH:5]=1)([O-])=O>CCOC(C)=O.[Fe]>[NH2:1][C:4]1[C:9]2[N:10]=[C:11]([C:13]([F:16])([F:15])[F:14])[O:12][C:8]=2[CH:7]=[CH:6][CH:5]=1

Participants

4

Reactant 1

HCID 218750194-Nitro-2-(trifluoromethyl)-1,3-benzoxazole

Product 1

HCID 218752592-(Trifluoromethyl)-4-benzoxazolamineYield 75%

Reagents, catalysts & solvents 2

HCID 23925IronCatalystHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
65 °C

Procedure

Compound 476A (10.75 g, 46.30 mmol) was dissolved in 1:1 EtOAc/10% HOAc (250 mL) and heated to 65° C. Iron powder (12.93 g, 231.5 mmol) was added portionwise and the reaction was stirred for 6 h at 65° C. After cooling, the mixture was filtered through Celite rinsing with EtOAc. The organic layer was separated, washed with H2O (3×100 mL), brine (100 mL), dried over MgSO4, and concentrated in vacuo to give a brown oil. The crude material was purified by flash chromatography on silica gel eluting with 70/30 CH2Cl2/hexanes to give compound 476B (7.02 g, 75%) as a yellow crystalline solid. HPLC: 96.7% at 2.68 min (retention time) (YMC S5 ODS column, 4.6×50 mm, eluting with 10-90% aqueous methanol over 4 mincontaining 0.2% phosphoric acid, 4 mL/min, monitoring at 220 nm).

Workup

  1. temperatureAfter cooling
  2. filtrationthe mixture was filtered through Celite
  3. washrinsing with EtOAc
  4. customThe organic layer was separated
  5. washwashed with H2O (3×100 mL), brine (100 mL)
  6. dry with materialdried over MgSO4
  7. concentrationconcentrated in vacuo
  8. customto give a brown oil
  9. customThe crude material was purified by flash chromatography on silica gel eluting with 70/30 CH2Cl2/hexanes

Sources & evidence

ORD record
ord-b44d3388ad714dc98221e1b5a5490271
Source dataset
uspto-grants-2008_12
Patent number
US07470797B2

Reaction notes

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