Easy Access to Pyranoacridines, Pyranoxanthenes, and Arylchromenes Through a Domino Reaction

Abstract

A series of pyrano[2,3,4‐kl]acridines has been synthesized through an unprecedented domino reaction involving1‐hydroxy‐3‐methoxy‐10‐methylacridone and Grignard reagents. This method has been successfully applied to xanthone, anthracenone, and benzophenone derivatives, thus providing novel access to pyranoxanthenes, dihydronaphthochromenes, and arylchromenes.

Isolation, Characterization of Undescribed Alkaloids, and Semisynthetic Modifications of Cytotoxic Pyranoacridone Alkaloids from Glycosmis pentaphylla

“…The major 2D correlations observed to characterize this compound are represented in Figure . Thus, the structure of 6 was confirmed as 1-hydroxy-3-methoxy-10-methyl-9-acridone based on the above-mentioned observations and reported literature . Compound 7 was obtained as an orange crystalline solid with the molecular formula of C 20 H 21 NO 3 as determined by the HRESIMS ion at m / z 324.1596 [M + H] + (calculated for 324.1594).…”

“…Thus, the structure of 6 was confirmed as 1-hydroxy-3-methoxy-10-methyl-9-acridone based on the above-mentioned observations and reported literature. 16 Compound 7 was obtained as an orange crystalline solid with the molecular formula of C 20 H 21 NO 3 as determined by the HRESIMS ion at m / z 324.1596 [M + H] + (calculated for 324.1594). The acridone scaffold of compound 7 is similar to that of compounds 5 and 6 , as shown in Figure 1 , except for the presence of a prenyl group at C-4.…”

“…mp 210−214 °C; 1 H NMR (500 MHz, CDCl 3 ): δ 8.34 (1H, d, J = 10 Hz), 7.55 (1H, t, J = 10 Hz), 7.41 (1H, d, J = 10 Hz), 7.21 (1H, t, J = 10 Hz), 6.60 (1H, d, J = 9.6 Hz), 6.31 (1H, s), 5.52 (1H, d, J = 9.6 Hz), 5.12 (1H, t, J = 7.5 Hz), 4.81 (2H, d, J = 6.2 Hz), 3.97 (3H, s), 1.60 (3H, s), 1.58 (3H, s), 1.53 (6H, s). 13 6-Methoxy-3,3-dimethyl-12-(prop-2-yn-1-yl)-3,12-dihydro-7H-pyrano [2,3-c]acridin-7-one (16). Column chromatography (SiO 2 100−200, eluted with 10% ethyl acetate) afforded the desired product as a pale-white crystalline solid (25 mg, 45% yield).…”

Studies Directed towards the Synthesis of the Acridone Family of Natural Products: Total Synthesis of Acronycines and Atalaphyllidines

“…We have first set our goal towards the synthesis of acronycine 1a and noracronycine 1b (Scheme ). The condensation of anthranilic acid 5a and phloroglucinol 6 in the presence of the catalytic amount of TsOH in n -hexanol provided the 1,3-dihydroxyacridone derivative 4a in excellent yield . The product was obtained in pure form by filtration without chromatographic purification.…”