p-Toluenesulfonic acid → 6-nitro-2,2,3-trimethyl-2H-1-benzopyran

HRID 1655372Notes

Reaction equation

HRID 1655372 reaction equation
[N+:1]([C:4]1[CH:5]=[CH:6][C:7]2[O:12][C:11]([CH3:14])([CH3:13])[CH:10]([CH3:15])[CH:9](O)[C:8]=2[CH:17]=1)([O-:3])=[O:2].C1(C)C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1>[N+:1]([C:4]1[CH:5]=[CH:6][C:7]2[O:12][C:11]([CH3:13])([CH3:14])[C:10]([CH3:15])=[CH:9][C:8]=2[CH:17]=1)([O-:3])=[O:2]

Participants

4

Reactant 2

HCID 6101p-Toluenesulfonic acidHCID 19387095HCID 19387095, compound

Product 1

HCID 157118816-nitro-2,2,3-trimethyl-2H-1-benzopyranYield 104.5%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A solution of 6-nitro-2,2,3-trimethyl-4-hydroxy-3,4-dihydro-2H-1-benzopyran (31.1 g, 0.131 mol) and p-toluenesulfonic acid (2.5 g, 0.013 mol) in toluene (875 ml) was refluxed for 18 hours, removing water with a Dean and Stark water separator. The cooled solution was washed with aqueous sodium bicarbonate solution and the organic phase separated. Solvent was removed under reduced pressure to give 30 g of 6-nitro-2,2,3-trimethyl-2H-1-benzopyran as an oil, 1H NMR (CDCl3): δ 1.45 (s, 6H) , 1.9 (s, 3H) , 6.15 (s, 1H), 6.8 (d, 1H), 7.8 (s, 1H), 8.0 (d,1H).

Workup

  1. customremoving water with a Dean and Stark water separator
  2. washThe cooled solution was washed with aqueous sodium bicarbonate solution
  3. customthe organic phase separated
  4. customSolvent was removed under reduced pressure

Sources & evidence

ORD record
ord-b85177c894304d58b4373b6ff5a36442
Source dataset
uspto-grants-1993_10
Patent number
US05250547

Reaction notes

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