Dimethylformamide → 2,6-Dibromo-4-fluorobenzaldehyde

A solution of 1,3-dibromo-5-fluoro-2-iodobenzene (50 g, 132 mmol) in anhydrous toluene (300 mL) cooled to −35° was added the solution of isopropylmagnesium chloride (84 mL, 171 mmol, 2.0 M in Et2O) over a period of 30 minute while maintaining the internal temperature below −25° (FIG. 6). A clear brown solution was obtained. Stirring was continued for 1.5 h. Then anhydrous DMF (34 mL, 436 mmol) was added over a period of 30 minutes. The temperature of the reaction mixture increased to −19°. The reaction mixture was warmed to 10° (room temperature) over 1 h and stirred at this temperature for 1.5 h. The reaction was quenched with saturated aqueous NH4Cl (100 mL), filtered and evaporated under reduced pressure. The residue was purified by silica-gel column chromatography (eluting with petroleum ether/ethyl acetate: from 50:1 to 20:1) to give 198a (20 g, yield 54%) as a yellow solid.

1. temperaturewhile maintaining the internal temperature below −25° (FIG. 6)
2. customA clear brown solution was obtained
3. temperatureThe temperature of the reaction mixture increased to −19°
4. stirringstirred at this temperature for 1.5 h
5. customThe reaction was quenched with saturated aqueous NH4Cl (100 mL)
6. filtrationfiltered
7. customevaporated under reduced pressure
8. customThe residue was purified by silica-gel column chromatography (eluting with petroleum ether/ethyl acetate: from 50:1 to 20:1)

ORD record

ord-4a951ff3896b439aa31eaa7d3ea7831b

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08618107B2