Improved synthesis of 4-phenylphenalenones: the case of isoanigorufone and structural analogs

4‐Phenylphenalenones as a template for new photodynamic compounds against Mycosphaerella fijiensis

“…). These compounds were obtained as products of different regioselectivity in the Friedel–Crafts reaction during the synthesis of 4‐phenylphenalenones . Compounds 13 and 14 contain the necessary 2‐arylnaphthalene moiety in a conformationally restricted configuration, in agreement with the A–B–D spatial distribution of the steroid nuclei.…”

“…Compounds 1 to 7 (Fig. ) were prepared according to our previously reported method . Briefly, the Michael addition of cyanoacrylate to 2‐naphthol followed by hydrolysis and Fisher esterification afforded ethyl 3‐(2‐hydroxynaphthalen‐1‐yl)propanoate which, upon triflation, generated ethyl 3‐(2‐{[(trifluoromethyl)sulfonyl]oxy}naphthalene‐1‐yl)propanoate.…”

“…Compounds 1 to 7 , 13 and 14 were prepared and purified as described earlier . Compounds 8 to 12 are also known; however, these were prepared by a different method.…”

“…Recently, we reported a nine‐step synthesis of 4‐phenylphenalenones, starting with 2‐naphthol, that allows for the preparation of structural analogues in sufficient quantities for biological assays . Here, the results of such assays conducted on Mycosphaerella fijiensis in the dark and under light‐controlled conditions are reported.…”

Direct and Short Construction of the ACDE Ring System of Daphenylline

“…Hydrolysis of 16 with LiOH⋅H 2 O generated the corresponding acid 5 , which was carried through the anticipated Friedel–Crafts acylation reaction to construct the D ring of daphenylline. To our delight, the crude compound 5 was transformed into the corresponding acyl chloride with thionyl chloride, followed by treatment with AlCl 3 in refluxing dichloromethane; this resulted in the ACDE ring system 4 in 69 % overall yield 17. Final confirmation of the stereochemistry of 4 was established by single‐crystal X‐ray analysis of a crystalline sample (Figure 2).…”