Syntheses of permethylated derivatives of pinastric acid and gomphidic acid, pulvinic acid pigments of lichen and fungi

Maleic anhydrides in synthesis. Preparation of furan-2(5H)-one phosphonate derivatives and a new synthesis of pulvinic acids and pulvinone analogues

“…OMe),6.28 (CH),6.49 (m, ArH), 7.02 (m, ArH), 7.36-7.46 (m, 3 x ArH), 7.51-7.55 (m, 2 x ArH) and 9.52 (NH); 6, 60.9 (q), 100.2 (d), 105.1 (s), 110.4 (d), 115.3 (d), 123.4 (d), 126.4 (d), 128.4 (d), 129.5 (s), 130.1 (d), 138.0 (s), 163.7 (s) and 168.4 (s) (Found: M+, 267.0895. C16H15N03 requires M, 267.0895); (b) the (E)isomer of the furanone (36 mg, 42%) (eluted second) as a crystalline yellow solid, m.p.…”

Naphthyl Tetronic Acids as Multi‐Target Inhibitors of Bacterial Peptidoglycan Biosynthesis

“…Bromofuranone 1 was acquired by bromination of the commercially available 4-methoxy-5H-furan-2-one with Nbromosuccinimide in carbon tetrachloride at reflux. [29] Deprotonation of 2 at C5 with lithium isopropylcyclohexylamide (LICA) [30] followed by an aldol reaction with substituted aldehydes 2 mediated by anhydrous ZnCl 2 afforded diastereomeric alcohols, which were converted into their mesylate or chloride derivatives in situ followed by elimination to generate the exocyclic double bond of 3 in the thermodynamically more stable Z configuration. [31] The key step involved a Suzuki cross-coupling of 3 with aryl boronic acids catalyzed by either [Pd- 2 ] to afford the methoxyfuranones 4 a-k. Demethylation of methoxyfuranones 4 a-k with lithium bromide [32] in the final step afforded the desired naphthylfuran-2ones 5 a-k. Purification by silica gel column chromatography was followed by an acid wash of the collected fractions to restore the acidic functionality.…”