N-bromobutanimide → HCID 86738627, compound

Participants

Reaction Steps

N-bromosuccinimide (14 mg) was added to a refluxing solution of 35 mg of triacetate (6) in 2 ml of CCl4 and the reaction mixture was refluxed further under argon atmosphere. After cooling in an ice-water bath, the resulting precipitate was filtered off. The filtrate was evaporated to dryness below 40° C. The residue is xylene (1 ml) was added dropwise to a refluxing solution of xylene (1.5 ml) and s-collidine (0.5 ml) and refluxing was continued under argon atmosphere for 20 min. The reaction mixture was extracted with AcOEt, washed with 2 N-HCl, sat. NaHCO3, brine and the solution was dried over MgSO4. After removal of the solvent, the residue was treated with a catalytic amount of pTsOH in acetone (10 ml) at room temperature for 16 hr under argon in the dark. The mixture was extracted with AcOEt and the extract was washed with sat. NaHCO3 and brine, and then dried over MgSO4. Removal of the solvent gave a crude 5,7-diene, which was purified by preparative TLC developed twice with a solvent of n-hexane-AcOEt (10:1). The band of Rf value 0.26 was scraped off and eluted with AcOEt. Removal of the solvent gave 8.8 mg (25%) of the product (7); UV(EtOH)λmax, 294, 282, 272 nm.

Provenance & Evidence