Hydrogen Bromide → Chromanone

Participants

Reaction Steps

Oxygen derivatives analogous to those of Examples IX and X may be prepared as follows: 9-acetyl-10-hydroxyphenanthrene and the appropriate aldehyde or ketone according to Example IX in benzene are added to a solution of sodium t-butoxide in benzene and the resulting mixture refluxed for 20 hours with stirring. The reaction mixture is poured into a stirred solution of hydrobromic acid (3 parts) and acetic acid (2 parts). The benzene layer is steam distilled and the residue boiled with methanol saturated with dry hydrogen chloride 0.5-1 hour to drive the cyclization to completion. After the solvent has been removed, the chroman-4-one is isolated by chromatography and crystallization from petroleum ether solvent.

Provenance & Evidence