Preparation of 4,6,3′,4′‐Tetrasubstituted Aurones via Aluminium Oxide‐Catalyzed Condensation.

Abstract

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Synthesis and herbicidal potential of substituted aurones

“…Reaction of compound 2 with methyl iodide in a molar ratio 1:317, 18 at 0 °C to room temperature gave a mixture of dimethoxy product 3 and unexpected product 4 . Compound 3 cannot be transformed to 4 in the presence of potassium carbonate and methyl iodide.…”

“…According to the literature,18 the iminium salt 1 was hydrolysed with aqueous hydrochloric acid to provide a mixture of benzofuranone 2 and 2′,4′,6′‐trihydroxy‐2‐chloroacetophenone; the mixture was treated with sodium methoxide to produce 2 . In the experiments it was found that the iminium salt 1 can directly be transformed in 77.3% yield to 2 in refluxing water, and the product can be used as starting material without any further purification.…”

“…The salt 1 was dissolved in 100 mL hot water and refluxed for 6 h. After cooling, the solid was filtered off, washed 3 times with water and dried to yield pure 4,6‐dihydroxybenzofuran‐3(2 H )‐one ( 2 ) as a dark red solid which was used without further purification. Yield 5.1 g (77.3%); mp 254–256 °C (literature: 210–212 °C,17 253–256 °C18); 1 H NMR (300 MHz, 50% DMSO‐ d 6 , 50% CDCl 3 ) δ: 4.50 (s, 2H, CH 2 ), 5.95 (dd, J 1 = 9.3 Hz, J 2 = 1.5 Hz, 2H, Ar‐H), 10.19 (brs, 1H, OH), 10.27 (brs, 1H, OH); 13 C NMR (75 MHz, 50% DMSO‐ d 6 , 50% CDCl 3 ) δ: 74.6, 90.2, 96.3, 102.6, 157.3, 167.8, 175.5, 194.2.…”

Synthesis and structural elucidation of two new series of aurone derivatives as potent inhibitors against the proliferation of human cancer cells

“…This is in accordance with the reported aurone derivatives having similar structural features (Bolek and Gutschow, 2005;Detsi et al, 2009;Seabra et al, 1997;Venkateswarlu et al, 2004). The Z-configuration was defined according to the chemical shift values of (C-10) of the exocyclic olefinic (=C-H) carbon (Fig.…”

Convenient Synthesis and Physiological Activities of Flavonoids in Coreopsis lanceolata L. Petals and Their Related Compounds

“…The protection of the hydroxyl group of 13a with MOMCl produced compound 13c with a 58% yield. The aldol condensation reaction, which is a key reaction in this process, of 13b , c with aromatic aldehydes 5a – f in the presence of aluminum oxide produced the corresponding aurones 14a – l with 31–89% yields [ 6 ]. In this reaction, the use of 13a resulted in decreasing yields.…”