Chemistry Letters, Vol.29, No.9, 1014-1015, 2000
Regioselective preparation of 1,6-and 1,8-dihydroxy-9,10-anthraquinones from the common intermediates: Synthesis of aloesaponarin I and K1115A
Treatment of 3-acyl-2-[(2,2-dimethyl-6-oxo-1,3-dioxin-4-yl)methyl]-5-methoxy-1,4-naph thoquinones with K2CO3 in an alcohol brought about the intramolecular condensation to give 1-alkyl-3-hydroxy-8-methoxy-9,10-anthraquinone-2-carboxylates in good yields, while the same naphthoquinone gave 1-hydroxy-8-methoxy-9,10-anthraquinone-3-acetic acid in good yield by treatment with KHMDS.