Hydrochloric Acid → 3-(3',5'-Dibromophenyl)-2-propenal

Temperatur

1 °C

3,5-dibromobenzaldehyde (16.1 g, 61.0 mmol) was added to a cold (ice-water bath) solution of tert-butoxide (13.0 g, 116 mmol), (1,3-dioxolan-2-ylmethyl)tri-n-butylphosphine bromide salt (4.5 M, 32 cm3, 144 mmol) in 400 cm3 of ether under argon. The mixture was stirred at 0-2° C. for 2 h. 1.0 M HCl(aq) (300 cm3) was added to the mixture. The reaction was gradually warmed to room temperature and stirred at room temperature for 21 h. The two layers were separated. The aqueous layer was extracted with ether (3×200 cm3). The organic layer and the ether extracts were combined, washed with brine (1×300 cm3) and dried over anhydrous magnesium sulfate. The solvents were completely removed to leave a yellow solid. The solid was purified by column chromatography of silica gel using ethyl acetate-light petroleum (40-60° C.) as eluent to give 3.36 g (19%) of A-1 as a colourless solid; δH (200 MHz; CDCl3) 6.68 (1 H, dd, J 7.4 & 16 Hz, vinylH), 7.33 (1 H, d, J 16 Hz, vinylH), 7.33 (2 H, m, ArH), 7.63 (1 H, m, ArH), and 9.72 (1 H, d, J7.6 Hz, CHO); m/z [CI(NH3)] 306, 308, 310 (MNH4+), and 288, 290, 292 (M+).

1. temperatureThe reaction was gradually warmed to room temperature
2. stirringstirred at room temperature for 21 h
3. customThe two layers were separated
4. extractionThe aqueous layer was extracted with ether (3×200 cm3)
5. washwashed with brine (1×300 cm3)
6. dry with materialdried over anhydrous magnesium sulfate
7. customThe solvents were completely removed
8. customto leave a yellow solid
9. customThe solid was purified by column chromatography of silica gel
10. customethyl acetate-light petroleum (40-60° C.)
11. customto give 3.36 g (19%) of A-1 as a colourless solid

ORD-Eintrag

ord-14d37fd5ea364d5f9e6e61854b4e26f7

Quelldatensatz

uspto-grants-2010_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07799917B2