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

HRID 892500Notes

Reaction equation

HRID 892500 reaction equation
[CH3:1][C:2]1([CH3:18])[CH2:7][CH:6]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][N:9]=2)[C:5]2[CH:14]=[CH:15][CH:16]=[CH:17][C:4]=2[O:3]1.ClC1C=CC=C(C(OO)=[O:27])C=1>ClCCl>[CH3:1][C:2]1([CH3:18])[CH2:7][CH:6]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][N+:9]=2[O-:27])[C:5]2[CH:14]=[CH:15][CH:16]=[CH:17][C:4]=2[O:3]1

Participants

4

Reactant 2

HCID 70297m-Chloroperbenzoic acid2×HCID 198956113,4-dihydro-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran

Product 1

HCID 538205312-(3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)pyridine N-oxideYield 76.3%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

130 mg of 3,4-dihydro-2,2-dimethyl-4-(2-pyridyl)-2H-1-benzopyran were dissolved in 10 ml of dichloromethane at room temperature and 93 mg of m-chloroperbenzoic acid were added. After 2 hours thin-layer chromatography indicated that some starting material was still present, whereupon further m-chloroperbenzoic acid was added until the reaction was complete. The mixture was washed in succession with sodium bisulphite solution, sodium bicarbonate solution and water, dried over sodium sulphate and evaporated to give 105 mg of 2-(3,4-dihydro-2,2-dimethyl-2H-1-benzopyran-4-yl)pyridine N-oxide in the form of an oil. NMR (300 MHz, CDCl3): 8.36-8.30 (1H, m) 7.21-7.04 (4H, m), 6.89-6.76 (3H, m), 5.36-5.25 (1H, m), 2.46 (1H, dd, 14Hz, 6.5Hz), 1.75 (1H, broad t, 14Hz), 1.44 (3H, s), 1.40 (3H, s). MS (EI): 255 (M+ , 238 (M+ --OH).

Workup

  1. additionwas added until the reaction
  2. washThe mixture was washed in succession with sodium bisulphite solution, sodium bicarbonate solution and water
  3. dry with materialdried over sodium sulphate
  4. customevaporated

Sources & evidence

ORD record
ord-e2c637847d394f0eb6888e5d78fedca3
Source dataset
uspto-grants-1992_06
Patent number
US05118694

Reaction notes

Loading…