Ozone → 7-Bromoheptanal

Temperature

-55 °C

A solution of 8-bromo-1-octene (5.0 g, 0.026 mol) in 25 mL of MeOH and 5 mL of CH2Cl2 was cooled to -40° C. and treated with O3 while the mixture was cooled to -50 to -60° C. After 30 min the mixture turned bluish and after another 10 min of O3 treatment the mixture was purged with a stream of N2 for 5 min. With the mixture still at -50° C. and covered with a blanket of N2, 2.5 mL of dimethylsulfide was added. This mixture was stirred for 1 h at -40° C., 1 h at -20° C. and then allowed to warm to -10° C. over 1 h. A vacuum from the water aspiration was applied to remove some of the excess dimethylsulfide, and the residue concentrated further on a rotary evaporator (house vacuum). The residue was treated with 10 mL of water and this mixture was extracted with hexane; the organic extracts were washed with water, then brine, dried (MgSO4) and concentrated. A portion of the crude product (0.7 g) was chromatographed under pressure to give 7-bromoheptaldehyde: NMR (CDCl3) δ1.41 (m, 4H), 1.63 (m, 2H), 1.87 (m, 2H), 2.45 (m, 2H), 3.41 (m, 2H), 9.78 (s, 1H).

1. customthe mixture was purged with a stream of N2 for 5 min
2. customstill at -50° C.
3. additionwas added
4. temperatureto warm to -10° C. over 1 h
5. customto remove some of the excess dimethylsulfide
6. concentrationthe residue concentrated further on a rotary evaporator (house vacuum)
7. additionThe residue was treated with 10 mL of water
8. extractionthis mixture was extracted with hexane
9. washthe organic extracts were washed with water
10. dry with materialbrine, dried (MgSO4)
11. concentrationconcentrated
12. customA portion of the crude product (0.7 g) was chromatographed under pressure

ORD record

ord-37bc01d365794139b51211ef77b50ede

Source dataset

uspto-grants-1995_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05405997