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ChemicalBook CAS DataBase List 9,9-DIMETHYL-9H-XANTHENE
19814-75-6

9,9-DIMETHYL-9H-XANTHENE synthesis

3synthesis methods
-

Yield:19814-75-6 85%

Reaction Conditions:

Stage #1:diphenylether with n-butyllithium in tetrahydrofuran at -78; for 3 h;Schlenk technique;
Stage #2:acetone in tetrahydrofuranSolvent;Temperature;

Steps:

1-3
Add 1.7g (10 mmol) of diphenyl ether and 50ml of anhydrous tetrahydrofuran to a 100ml Schlenk flask, and then place the reaction flask in a low-temperature reaction bath.Stir and cool down to -78°C, then use a syringe to drop 8ml (20mmol, concentration 2.5M) of n-butyllithium into the reaction flask. After reacting for 3 hours,0.58g (10 mmol) acetone was added dropwise, and then 20ml water was added to quench the reaction,Separate the organic phase, spin down the organic solvent,The obtained crude product was purified by column chromatography to obtain 1.79 g of light yellow solid. The product was confirmed to be 9,9'-dimethylxanthene in structure by 1H-NMR and 13C-NMR. The yield was 85%. The purity of the product was analyzed by liquid chromatography. 99.5%.

References:

Li Heng;Geng Weizhi CN112062745, 2020, A Location in patent:Paragraph 0019-0021

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