Potassium Carbonate → 3-Methyl-5-nitro-1,2-benzoxazole

HRID 873845Notes

Reaction equation

HRID 873845 reaction equation
[NH:1]=[C:2]([C:4]1[CH:9]=[C:8]([N+:10]([O-:12])=[O:11])[CH:7]=[CH:6][C:5]=1[OH:13])[CH3:3].ClN1C(=O)CCC1=O.C([O-])([O-])=O.[K+].[K+]>C1COCC1>[CH3:3][C:2]1[C:4]2[CH:9]=[C:8]([N+:10]([O-:12])=[O:11])[CH:7]=[CH:6][C:5]=2[O:13][N:1]=1

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 31398ChlorosuccinimideHCID 1370147772(1-Iminoethyl)-4-nitrophenol

Product 1

HCID 124113183-Methyl-5-nitro-1,2-benzoxazoleYield 96.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a stirred suspension of 2-(1-iminoethyl)-4-nitrophenol (Step 33.1) (2.94 g, 16.32 mmol) in THF (40 mL) was added N-chlorosuccinimide (3.27 g, 24.48 mmol) and K2CO3 (4.51 g, 32.6 mmol) under Ar. The reaction mixture was stirred for 3 hr at rt, quenched with brine, and extracted with EtOAc. The combined organic layers were washed with a saturated aq. NaHCO3 solution, dried over Na2SO4 and evaporated. The crude product was purified by silica gel column chromatography (hexane/EtOAc 5-15%) to afford the title product (2.8 g, 15.72 mmol, 96% yield) as a white solid. tR: 4.31 min (HPLC 1); tR: 0.86 min (LC-MS 2); ESI-MS: 179 [M+H]+ (LC-MS 2); Rf=0.85 (hexane/EtOAc 1:1).

Workup

  1. customquenched with brine
  2. extractionextracted with EtOAc
  3. washThe combined organic layers were washed with a saturated aq. NaHCO3 solution
  4. dry with materialdried over Na2SO4
  5. customevaporated
  6. customThe crude product was purified by silica gel column chromatography (hexane/EtOAc 5-15%)

Sources & evidence

ORD record
ord-2a49fe3c14c94f3ab2992f355c41a8ca
Source dataset
uspto-grants-2015_03
Patent number
US08975417B2

Reaction notes

Loading…