Hydrochloric Acid → 2,2,7-Trimethyl2H-pyrano[2,3-g]quinoline

HRID 1993460Notes

Reaction equation

HRID 1993460 reaction equation
[NH2:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][C:7]([CH3:13])([CH3:12])[CH:6]=[CH:5]2.Cl.[C:15]1(Cl)[C:21](=O)C(Cl)=C(Cl)[C:17](=O)[C:16]=1Cl.C(=O)([O-])O.[Na+]>C(O)CCC.O1CCCC1.[Cl-].[Zn+2].[Cl-]>[CH3:12][C:7]1([CH3:13])[O:8][C:9]2=[CH:10][C:11]3[CH:21]=[CH:15][C:16]([CH3:17])=[N:1][C:2]=3[CH:3]=[C:4]2[CH:5]=[CH:6]1

Participants

8

Reactant 4

HCID 313Hydrochloric AcidHCID 8371ChloranilHCID 516892Sodium BicarbonateHCID 100808812,2-Dimethyl-2H-chromen-6-amine

Product 1

HCID 591343912,2,7-Trimethyl2H-pyrano[2,3-g]quinolineYield 22%

Reagents, catalysts & solvents 3

HCID 3007855ZincchlorideCatalystHCID 2631-ButanolSolvent2×HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
120 °C

Procedure

To 6-amino-2,2-dimethylchromene (1.00 g, 5.71 mmol), 35% hydrochloric acid (1.43 mL, 17.1 mmol), p-chloranil (1.40 g, 5.71 mmol) and n-butanol (1.3 mL) were added at room temperature and the temperature was increased to 120° C. A solution of crotyl aldehyde (0.567 mL, 6.84 mmol) in n-butanol (0.52 mL) was added and the resulting mixture was stirred at 120° C. for 20 minutes. A solution of zinc chloride (0.777 g, 5.71 mmol) in tetrahydrofuran (10 mL) was added, and the resulting mixture was stirred at 120° C. for 20 minutes. Upon the completion of the reaction, aqueous sodium hydrogencarbonate solution was added, and the resulting solution was extracted with ethyl acetate and dried over anhydrous magnesium sulfate. After distilling off the solvent, the residue was purified by column chromatography (hexane/ethyl acetate=2/1), and recrystallized from ethyl acetate to obtain the aimed product (yield: 22%).

Workup

  1. stirringthe resulting mixture was stirred at 120° C. for 20 minutes
  2. additionwas added
  3. extractionthe resulting solution was extracted with ethyl acetate
  4. dry with materialdried over anhydrous magnesium sulfate
  5. distillationAfter distilling off the solvent
  6. customthe residue was purified by column chromatography (hexane/ethyl acetate=2/1)
  7. customrecrystallized from ethyl acetate

Sources & evidence

ORD record
ord-3dffc891d8fb43fab07e5cefe2e1d3a5
Source dataset
uspto-grants-2010_01
Patent number
US07652008B2

Reaction notes

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