Sodium Carbonate → 2,7-Dimethoxyfluorenone

HRID 1598343Notes

Reaction equation

HRID 1598343 reaction equation
[OH:1]C1C=CC2C3C(=CC(O)=CC=3)C(=O)C=2C=1.Br[C:18]1[CH:27]=[CH:26][C:25]([O:28][CH3:29])=[CH:24][C:19]=1[C:20](OC)=O.[CH3:30][O:31][C:32]1[CH:37]=[CH:36][C:35](B(O)O)=[CH:34][CH:33]=1.C(=O)([O-])[O-].[Na+].[Na+]>[Pd].[Pd].C(=CC(C=CC1C=CC=CC=1)=O)C1C=CC=CC=1.C(=CC(C=CC1C=CC=CC=1)=O)C1C=CC=CC=1.C(=CC(C=CC1C=CC=CC=1)=O)C1C=CC=CC=1.C(COC)OC>[CH3:29][O:28][C:25]1[C:24](=[O:1])[C:19]2[C:18](=[CH:27][CH:26]=1)[C:35]1[C:34](=[CH:33][C:32]([O:31][CH3:30])=[CH:37][CH:36]=1)[CH:20]=2

Participants

7

Reactant 4

HCID 10340Sodium CarbonateHCID 201262(4-Methoxyphenyl)boronic acidHCID 2776849Methyl 2-bromo-5-methoxybenzoateHCID 43541812,7-Dihydroxyfluoren-9-one

Product 1

HCID 702692002,7-Dimethoxyfluorenone

Reagents, catalysts & solvents 2

HCID 9832798Tris(dibenzylideneacetone) dipalladiumCatalystHCID 80711,2-DimethoxyethaneSolvent

Procedure

Prepared analogously to 2-[9-(2-Methoxyfluorenyl)]ethylamine hydrochloride in Example 1 beginning with 2,7-dihydroxy-9-fluorenone. 1H NMR (300 MHz, CDCl3) δ 7.60 (d, J=8.0 Hz, 2H), 7.00 (d, J=2.0 Hz, 2H), 7.85 (dd, J=8.0, 2.0 Hz, 2H), 3.90-4.10 (m, 1H), 3.85 (s, 6H), 2.50-2.60 (m, 2H), 2.10-2.30 (m, 2H). Alternatively, the necessary intermediate 2,7-dimethoxyfluorenone was prepared as follows: Methyl 2-bromo-5-methoxybenzoate (1.60 g, 6.53 mmol), 4-methoxyphenylboronic acid (1.30 g, 8.55 mmol), and tris(dibenzylideneacetone) dipalladiurn (0) (0.20 g, 0.22 mmol) were added to dimethoxyethane (25 mL) and 2M sodium carbonate (25 mL). The reaction was stirred at reflux for 16 h then decanted and the residue extracted with ethyl acetate. The combined organic layers were dried (MgSO4) and the solvent removed by rotary evaporation to afford 1.50 g of the coupled product (5.51 mmol, 84% yield). The ester (10.80 g, 39.70 mmol) was hydrolyzed with 1N sodium hydroxide (80 mL) in refluxing ethanol (500 mL). The cooled reaction mixture was extracted with methylene chloride and then acidified with 1N hydrochloric acid. The acidic solution was then extracted with methylene chloride. The organic layers were combined and the solvent was dried and concentrated by rotary evaporation to give 9.00 g (34.88 mmol, 88% yield) of the acid. 9.00 g (34.88 mmol) of the acid was dissolved in thionyl chloride (250 mL) and stirred at reflux for 6 h. The reaction was cooled to ambient temperature and the solvent was removed by rotary evaporation to give 8.20 g of 2,7-dimethoxyfluorenone (34.17 mmol, 98% yield) as a red solid.

Workup

  1. temperatureat reflux for 16 h
  2. customthen decanted
  3. extractionthe residue extracted with ethyl acetate
  4. dry with materialThe combined organic layers were dried (MgSO4)
  5. customthe solvent removed by rotary evaporation

Sources & evidence

ORD record
ord-6905c89d33f9490c8a20786dc98a4d35
Source dataset
uspto-grants-1998_04
Patent number
US05736578

Reaction notes

Loading…