2,2-Dimethyl-7-nitro-2H-chromen-6-amine → 2,2-Dimethyl-7-nitro-2h-1-benzopyran

HRID 505649Notes

Reaction equation

HRID 505649 reaction equation
N[C:2]1[C:3]([N+:14]([O-:16])=[O:15])=[CH:4][C:5]2[O:10][C:9]([CH3:12])([CH3:11])[CH:8]=[CH:7][C:6]=2[CH:13]=1.N([O-])=O.[Na+]>CO.[PH2](O)=O>[CH3:11][C:9]1([CH3:12])[CH:8]=[CH:7][C:6]2[CH:13]=[CH:2][C:3]([N+:14]([O-:16])=[O:15])=[CH:4][C:5]=2[O:10]1

Participants

5

Reactant 2

HCID 132228932,2-Dimethyl-7-nitro-2H-chromen-6-amineHCID 23668193Sodium Nitrite

Product 1

HCID 132228872,2-Dimethyl-7-nitro-2h-1-benzopyranYield 61%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 4124402Phosphinic AcidSolvent

Procedure

To a mixed solution of 6-amino-2,2-dimethyl-7-nitro-1-benzopyran (19.5 g, 88.7 mmol) in methanol-concentrated hydrochloric acid (1:1 v/v, 280 mL) and hypophosphorous acid aqueous solution (100 mL), an aqueous solution of sodium nitrite (12.2 g, 178 mmol) was added dropwise over 30 minutes at −3° C., and the resulting solution was stirred at room temperature until bubbling ceased. The reaction solution was diluted with ethyl acetate, washed with water and saturated sodium chloride solution. The organic phase was dried over magnesium sulfate and then concentrated under a reduced pressure. The resulting solid was recrystallized in methanol to obtain 2,2-dimethyl-7-nitro-1-benzopyran (yield: 61%).

Workup

  1. customuntil bubbling
  2. additionThe reaction solution was diluted with ethyl acetate
  3. washwashed with water and saturated sodium chloride solution
  4. dry with materialThe organic phase was dried over magnesium sulfate
  5. concentrationconcentrated under a reduced pressure
  6. customThe resulting solid was recrystallized in methanol

Sources & evidence

ORD record
ord-ed26b227609b44c5b8f0f33a176e6743
Source dataset
uspto-grants-2010_08
Patent number
US07781483B2

Reaction notes

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