Regiodefined synthesis of brominated hydroxyanthraquinones related to proisocrinins

• Joyeeta Roy,
• Tanushree Mal,
• Supriti Jana and
• Dipakranjan Mal

Beilstein J. Org. Chem. 2016, 12, 531–536, doi:10.3762/bjoc.12.52

• condensation; Hauser annulation; proisocrinins; Introduction Anthraquinones constitute the largest group of naturally occurring quinones [1][2][3][4][5]. Isolated mainly from fungal sources, they display a wide range of biological activities which include anti-inflammatory, antifungal, antiparasidal, and

• inhibitory activity against human tumor cell lines SF-268, MCF-7, and NCI-H460, with IC50 values of 7.11, 6.64, and 7.42 μM, respectively [12]. Proisocrinins A–F (6–11), recently isolated from the stalked crinoid Proisocrinus ruberrimus (Figure 1) are the first water soluble natural anthraquinone pigments

• the bromoanthraquinone scaffolds of proisocrinins 6–11. Results and Discussion First synthetic route Anthraquinone 14 was proposed to be synthesized by the Hauser annulation of cyanophthalide 12 and cyclohexenone 13 (Scheme 1). A functional group manipulation of 14 was expected to give anthraquinone