m-Chloroperbenzoic acid → 2-(3,4-dihydro-2,2-dimethyl-6-nitro-2H-1-benzopyran-4-yl)pyridine N-oxide

HRID 1073867Notes

Reaction equation

HRID 1073867 reaction equation
[CH3:1][C:2]1([CH3:21])[CH2:7][CH:6]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][N:9]=2)[C:5]2[CH:14]=[C:15]([N+:18]([O-:20])=[O:19])[CH:16]=[CH:17][C:4]=2[O:3]1.ClC1C=CC=C(C(OO)=[O:30])C=1>ClCCl>[CH3:1][C:2]1([CH3:21])[CH2:7][CH:6]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][N+:9]=2[O-:30])[C:5]2[CH:14]=[C:15]([N+:18]([O-:20])=[O:19])[CH:16]=[CH:17][C:4]=2[O:3]1

Participants

4

Reactant 2

HCID 70297m-Chloroperbenzoic acid2×HCID 198955943,4-dihydro-2,2-dimethyl-6-nitro-4-(2-pyridyl)-2H-1-benzopyran

Product 1

HCID 221569362-(3,4-dihydro-2,2-dimethyl-6-nitro-2H-1-benzopyran-4-yl)pyridine N-oxideYield 30.9%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

245 mg of 3,4-dihydro-2,2-dimethyl-6-nitro-4-(2-pyridyl)-2H-1-benzopyran were dissolved in 5 ml of dichloromethane at room temperature and 149 mg of m-chloroperbenzoic acid were added. After stirring at room temperature for 3 days further m-chloroperbenzoic acid was added until starting material could no longer be detected by thin-layer chromatography. The mixture was washed in succession with sodium bisulphite solution, sodium bicarbonate solution and sodium chloride solution, dried over sodium sulphate and evaporated. The residue was chromatographed on silica gel using 4% (v/v) ethanol/dichloromethane for the elution and the resulting foam was triturated with n-hexane to give 80 mg of 2-(3,4-dihydro-2,2-dimethyl-6-nitro-2H-1-benzopyran-4-yl)pyridine N-oxide of melting point 116-119° C.

Workup

  1. additionwas added
  2. washThe mixture was washed in succession with sodium bisulphite solution, sodium bicarbonate solution and sodium chloride solution
  3. dry with materialdried over sodium sulphate
  4. customevaporated
  5. customThe residue was chromatographed on silica gel using 4% (v/v) ethanol/dichloromethane for the elution
  6. customthe resulting foam was triturated with n-hexane

Sources & evidence

ORD record
ord-fd42966213824bb4b59b186b68d4b67e
Source dataset
uspto-grants-1990_11
Patent number
US04971982

Reaction notes

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