Reactions of Acenaphthenequinone and Aceanthrenequinone with Arenes in Superacid.
The hydroxyalkylation reactions of aceanthrenequinone (6) and acenapthenequinone (7) with a series of arenes have been studied. In reactions with the Brønsted superacid CF(3)SO(3)H (triflic acid), the condensation products are formed in good yields (58-99%, 10 examples) with high regioselectivity. Computational studies were also done to examine the structures and energies of mono- and diprotonated species from 6 and 7. The results from the condensation reactions are consistent with the formation of superelectrophilic species involving protosolvation of carboxonium ion intermediates.
Objective To study the chemical constituents from the fresh herb of Stellaria media.Methods The chemical constituents of the plant were isolated and purified by column chromatography and their structures were elucidated by spectroscopic analysis. Results Five chemical constituents were isolated and elucidated as apigenin (1), 6,8-di-C-glucopyranosyl apigenin (2), quercitin 3-Ο-α-L-rhamnoside (3), querctin (4), daucosterol (5), respectively. Conclusion Compounds 3, 4, and 5 were isolated from this plant for the first time.