New Convenient Synthesis of Homoisoflavanones and (±)‐Di‐O‐methyldihydroeucomin

Abstract

For Abstract see ChemInform Abstract in Full Text.

Synthesis of (±) homoisoflavanone and corresponding homoisoflavane

“…The aldol condensation of 5 with 4-methoxybenzaldehyde under alkaline condition in EtOH afforded chalcone (6) in 61.8% yield, and following hydrogenation using Pd/C as the catalyst in THF at room temperature gave dihydrochalcone (7) in 84.5% yield. It had been reported that the conversion of dihydrochalcones into the corresponding homoisoflavones could be achieved by treating them with (MeO) 2 CHNMe 2 [8], HCOOEt/Na [11], DMF/MeSO 2 Cl [12], or DMF/PCl 5 [13]. All methods described above had been tested for the preparation of homoisoflavone (8), and the last one was proved to be the most efficient.…”

“…It had been reported that the conversion of dihydrochalcones into the corresponding homoisoflavones could be achieved by treating them with (MeO) 2 CHNMe 2 [8], HCOOEt/Na [11], DMF/MeSO 2 Cl [12], or DMF/PCl 5 [13]. All methods described above had been tested for the preparation of homoisoflavone (8), and the last one was proved to be the most efficient. Thus, the treatment of 7 with DMF and PCl 5 in the presence of Lewis acid, BF 3 ·Et 2 O, afforded 8 in 71.0% yield.…”

“…Thus, the treatment of 7 with DMF and PCl 5 in the presence of Lewis acid, BF 3 ·Et 2 O, afforded 8 in 71.0% yield. The next step for the synthesis of homoisoflavanone ((^) 1) was the catalytic hydrogenation of homoisoflavone (8).…”

“…Several methods for the synthesis of homoisoflavanones have been reported in the literatures, which were mainly based on (i) the Friedel -Crafts acylation of racemic or optical 2-benzyl-3-phenoxypropanoic acids in the presence of trifluoroacetic acid and trifluoroacetic anhydride [5], (ii) the catalytic hydrogenation of 3-benzylidenechroman-4-ones obtained via the aldol condensation of 4-chromanones with benzaldehydes [6], (iii) the Michael-type addition of 2-benzyl-1-(2-hydroxyphenyl)prop-2-en-1-one derivatives [7], and (iv) the catalytic hydrogenation of homoisoflavones that could be prepared from dihydrochalcones [8]. In the present work, we employed method (iv) as our strategy for the synthesis of the racemic homoisoflavanone ((^) 1), which is described in Scheme 1.…”

Synthesis and Vasodilatation of Homoisoflavones

“…当体 系由黄色变为绿色再到黑色时(静置后溶液为无色), 停 止反应, 此时刚好选择性地还原双键, 同时保留了苄基. 在制备化合物 c1～c6 和 c13～c18 时, 采用文献报 道的方法 [4,20,21] , ＋ . …”