Reaction #2460291

Reaction equation

2,4-di-(tert-amyl)phenoxybenzoic acid

acetic anhydride

sulfuric acid

→

2,4-di-(tert-amyl)xanthen-9-one

Solvents

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was cooled to ambient and
2. 2
   ExtractionThe aqueous phase was extracted twice with dichloromethane
3. 3
   Washthe combined organic extracts were washed with water
4. 4
   DryingThe solution was dried (Na2SO4)
5. 5
   Concentrationconcentrated deposit a brown solid
6. 6
   OtherThe product was purified by column chromatography
7. 7
   Otherto provide 3.5 g (76% of theory) of a white solid

Procedure

Finally, 2,4-di-(tert-amyl)xanthen-9-one (S-13) was prepared. To a suspension of 2,4-di-(tert-amyl)phenoxybenzoic acid (4.8 g, 13.6 mmol) in acetic anhydride (27.7 g, 272 mmol) was added dropwise sulfuric acid (1.33 g, 13.6 mmol), and then the mixture was held at 80° C. for 3 h. The reaction mixture was cooled to ambient and poured into 100 mL of ice water. The aqueous phase was extracted twice with dichloromethane, and the combined organic extracts were washed with water and then with brine. The solution was dried (Na2SO4) and concentrated deposit a brown solid. The product was purified by column chromatography to provide 3.5 g (76% of theory) of a white solid. 1H NMR (CDCl3): δ 0.75 (t, 6H), 1.3 (s, 6H), 1.4 (s, 6H), 1.65 (q, 2H), 1.80 (q, 2H), 3.85 (s, 3H), 6.80 (d, 2H), 7.15 (m, 2H), 7.35 (br s, 1H), 7.45 (t, 1H), 8.2 (d, 1H).

Source