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ChemicalBook CAS DataBase List 4-Bromo-9H-fluoren-9-one
4269-17-4

4-Bromo-9H-fluoren-9-one synthesis

10synthesis methods
2'-BROMOBIPHENYL-2-CARBONITRILE

54245-41-9

4-Bromo-9H-fluoren-9-one

4269-17-4

To a 500 mL three-necked flask were sequentially added 50 mL of benzyl cyanide, 70.7 g (0.3 mol) o-dibromobenzene and 68.4 g (0.45 mol) cesium fluoride. Under argon protection, 0.86 g (1.5 mmol) of bis(dibenzylideneacetone)palladium, 2.86 g (15 mmol) of thiophene-2-carboxylate, and 7.0 g (15 mmol) of 1,1'-bis(di-tert-butylphosphino)ferrocene were added as catalyst. The reaction mixture was stirred at 150°C for 24 hours. After completion of the reaction, it was cooled to room temperature, the reaction mixture was filtered and the filtrate was distilled to remove benzyl cyanide to give the crude product 2-bromo-2'-carbonitrile biphenyl. The crude product was transferred to another 500 mL three-necked flask and 80 mL of glacial acetic acid and 80 mL of concentrated sulfuric acid were added. After heating and refluxing for 12 hours, it was cooled to room temperature and filtered to obtain a dark yellow solid. The solid was washed with 100 mL of water and 100 mL of methanol and finally recrystallized from 200 mL of isopropylbenzene to give 61.9 g (80% yield) of 4-bromo-9H-fluoren-9-one as a yellow solid.

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Yield:4269-17-4 80%

Reaction Conditions:

with sulfuric acid;acetic acid for 12 h;Reflux;

Steps:

3 Example 3

To a 500 mL reaction flask, 50 mL of benzonitrile was added successively,70.7 g (0.3 mol) of o-dibromobenzene,68.4 g (0.45 mol) of cesium fluoride,Catalyst purged with argon was added bis (dibenzylideneacetone) palladium 0.86g (15mmol),Thiophene-2-carboxylate 2.86 g (15 mmol)And 7.0 g (15 mmol) of 1,1'-bis (di-t-butylphosphine) ferrocene,150 reaction 24h,filter,The filtrate was distilled to remove benzonitrile to give crude 2-bromo-2'-carbonitrile biphenyl.A 500 mL reaction flask was charged with crude 2-bromo-2'-carbonitrile biphenyl,Glacial acetic acid 80mL,Concentrated sulfuric acid 80mL.After heating and refluxing for 12 h,Cooled to room temperature,filter,To give a dark yellow solid,100 mL of water,100 mL of methanol,Recrystallization from 200 mL of cumene afforded 61.9 g of 4-bromofluorenone as a yellow solid in 80% yield.

References:

CN105237379,2016,A Location in patent:Paragraph 0006; 0016

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