Dimethylformamide → 2,4-Difluorobenzaldehyde

Temperature

-75 °C

2,4-Difluorobromobenzene (18.5 g) was added to dry diethyl ether (150 ml), cooled to -75° C. and n-butyllithium (61 5 ml of a 1.55 molar solution in hexane) was added under dry nitrogen over a period of 45 minutes. The mixture was stirred at -70° C. for a further 20 minutes and dry dimethylformamide (7.65 g) was added in dry diethyl ether (30 ml) at -70° C. over a period of 30 minutes. The mixture was stirred for 40 minutes and allowed to warm to -50° C. over a further 15 minutes. A solution of ammonium chloride (30 g) in water (100 ml) was added and the ether layer separated. The aqueous layer was further extracted with diethyl ether (2×50 ml) and the combined ethereal extracts were dried and evaporated to yield a pale yellow oil which was distilled at the water pump to give the desired product (13.0 g) b.p. 52°-55° C. at 14 mm Hg.

1. stirringThe mixture was stirred for 40 minutes
2. temperatureto warm to -50° C. over a further 15 minutes
3. customthe ether layer separated
4. extractionThe aqueous layer was further extracted with diethyl ether (2×50 ml)
5. customthe combined ethereal extracts were dried
6. customevaporated
7. customto yield a pale yellow oil which
8. distillationwas distilled at the water pump

ORD record

ord-70237e3df4b84b51b320cf5e8f34bf80

Source dataset

uspto-grants-1986_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04616026