Hydrogen Bromide → 12-Bromo-12,12-difluorododecanyl acetate

Participants

Reaction Conditions

Reaction Steps

Acetic anhydride, 37 ml, was added slowly dropwise to 10 ml of stirred 47% hydrobromic acid. Upon completion of addition, 10.0 grams (0.045 mole) of 12,12-difluoro-11-dodecen-1-ol (prepared in Example 5) was added dropwise. Following this addition the reaction mixture was warmed to 100° C. where it was stirred for three hours. The reaction mixture was cooled to ambient temperature and then was extracted with three 20 ml portions of methylene chloride. The combined extracts were in turn washed with one 15 ml portion of water, three 15 ml portions of an aqueous solution saturated with sodium bicarbonate, one 15 ml portion of water, one 15 ml portion of aqueous 1N hydrochloric acid, one 15 ml portion of water and one 15 ml portion of an aqueous solution saturated with sodium chloride. The organic layer was dried with magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure to a residual oil. The oil was subjected to column chromatography on silica gel. Elution was accomplished using 10% ethyl acetate in heptane. The appropriate fractions were combined and concentrated under reduced pressure yielding 2.8 grams of 12-bromo-12,12-difluorododecanyl acetate. The nmr spectrum was consistent with the proposed structure.

Provenance & Evidence