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

• biomimetic aldol condensations [17][18][19][20][21][22][23], and reports on the synthesis of brominated anthraquinones are scare [12][13][14][15]. Having inspired by the convergence and the regiochemical integrity of the Hauser annulation [24][25][26][27][28][29][30], we explored it for the construction of

• 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