Total Synthesis of Bisbibenzylic Compounds Isolated From Bryophytes

Microwave accelerated solvent-free synthesis of flavanones

“…22 A study on the microwave-induced cyclization of o-hydroxychalcones, 1, to flavanones, 2, on different supports resulted in an equilibrium mixture of 1 and 2; no significant difference was found between the equilibrium ratio 2:1 of microwave-induced or conventional thermal cyclization. 3 As part of an ongoing project on the synthesis and biological evaluation of flavonoids and other phenolic compounds, 9,23,24 an easy and reliable method for the preparation of flavanones was needed. We had previously studied the cyclization of 2'-hydroxy-4-methoxychalcone, 3, to 4'-methoxyflavanone, 4, as a model and, among various catalysts, we found that 4 was best prepared by refluxing the corresponding chalcone in acetic acid for 72 hours, although in moderate yields (55%) (Scheme 2).…”

Nematocidal Activity of Natural Polyphenols from Bryophytes and their Derivatives

“…Elemental analyses, obtained from vacuum-dried samples on a CHN-S analyzer from Fison Instruments (St. Rivoltana, Rodano, MI, Italy), gave satisfactory results: C, H ± 0.3. Compounds 1 [10], 3 [12], 4 [10], 6−8 [12,15], and 9−12 [10] were obtained using reported procedures.…”

“…To a suspension of lithium aluminum hydride (0.3 g, 8.0 mmol) in 40 ml of dry THF was slowly added a solution of diphenylether 4 [10] (0.7 g, 2.5 mmol in 10 ml of THF). During the addition, the solvent started boiling and the reflux was maintained for 1 h. Then, the reaction was cooled in an ice bath and the solution was slowly poured into ice-water.…”

“…Aldehyde 12 (1.52 g, 4.2 mmol) and (2,3-dimethoxybenzyl)triphenylphosphonium chloride [10] (1.77 g, 4.3 mmol) were dissolved in the minimum amount of dry toluene, and dry potassium carbonate (1.2 g, 8.6 mmol) and a tip of spatula of 18:crown:6 ether were added at ambient temperature. The reaction mixture was heated to reflux for 18 h. The solvent was evaporated under vacuum and the crude stilbene 13 was purified by column chromatography (silica gel/CH 2 Cl 2 ).…”

“…In a previous paper we described the preparation of compounds 4, 9, 10, 11, and 12 in multigram scale for the total synthesis of 14'-hydroxyperrottetin E (1) [10]. The same set of intermediates was used for the preparation of 10'-hydroxyperrottetin (2) (Scheme 3).…”