Unsaturated steroids. Part 2. A novel route to anthrasteroids: X-ray crystal structure of 1(10 → 6)abeo-cholesta-5,7,9-trien-3-yl p-bromobenzoate

Abstract

Treatment of the adduct from a steroidal 5,7-diene and 4-phenyl-1,2,4-triazoline-3,5-dione with boron trifluoride–diethyl ether gives the corresponding anthrasteroid. The structure of the product derived from cholesta-5,7-dien-3β-ol has been determined by X-ray crystallography. Oxidation of the anthrasteroid with the Moffat reagent furnishes the corresponding 3-ketone, which can be dehydrogenated with tri-N-methylanilinium perbromide to the corresponding naphthol. The various anthrasteroids are oxidised by dichlorodicyano-1,4-benzoquinone to the corresponding 14-enes.