Herstellung von Anthrachinonderivaten aus dem DIELS‐ALDER‐Addukt von 1,4‐Naphtochinon und 5,5‐Dimethoxy‐1,2,3,4‐tetrachlorcyclopentadien. 2. Mitteilung

Abstract

AbstractThe DIELS‐ALDER adduct of 1,4‐naphthoquinone and 5,5‐dimethoxy‐1,2,3,4‐tetrachlorocyclopentadiene was transformed into the di‐O‐acetyl‐dienol (80%) which, on oxidation with chromium trioxide, gave 2,3,4‐trichloranthraquinone‐1‐carboxylic acid methylester (72%). Sodium dithionite treatment of this compound yielded 2,3‐dichloroanthraquinone‐1‐carboxylic acid (80%). Pyrolysis of the DIELS‐ALDER adduct and the diacetyldienol, followed by oxidation, led to 2,3,4‐trichloroanthraquinone‐1‐carboxylic acid methylester (9,5%) and 1,2,3,4‐tetrachloroanthraquinone (29%), respectively.