Synthesis of Isoflavones from 2′‐Hydroxychalcones Using Poly[4‐(diacetoxy)iodo]styrene or Related Hypervalent Iodine Reagent.

Abstract

Oxidation of a methanolic solution of chalcones with hypervalent iodine compounds results in a rearrangement to acetals, if the substrates lack the 2'-hydroxy group [cf. (IV)]. One-pot hydrolysis of the 2-benzoyloxy derivatives (VII) leads to an efficient synthesis of chalcones such as (VIII). Polymer-supported diacetoxyiodostyrene is used under similar conditions. The yields are lower; however, the isoflavones can be easily separated, no Ph-I is liberated and the reagent can be reused. -(KAWAMURA*, Y.; MARUYAMA, M.; TOKUOKA, T.; TSUKAYAMA, M.; Synthesis

Inhibition of cancer cell invasion and metastasis by genistein

“…In the chalcone route, a chalcone substrate is generated by an aldol reaction between an appropriate acetophenone and an aromatic aldehyde. Oxidative rearrangement of the chalcone substrate by utilizing either a thallium(III) or hypervalent iodide reagent in methanol, followed by base-mediated ring closure, yields the final desired products [ 26 ]. Although these two routes are used to construct bulk quantities of synthetic genistein, other methods such as the Suzuki-Miyaura cross-coupling of arylboronic acids and halochromones are often used to generate smaller amounts of material for biological analysis [ 27 , 28 ].…”

Process for the Preparation of Chromones, Isoflavones and Homoisoflavones Using Vilsmeier Reagent Generated from Phthaloyl Dichloride and DMF

“…The two most popular pathways for the synthesis of isoflavones are the deoxybenzoin and the chalcone routes. In the first route, isoflavones are synthesized by the ring closure of deoxybenzoin with C 1 unit by using different reagents such as ethoxalylchoride in pyridine [12], triethylorthoformate with pyridine and piperidine [13], N, N-dimethylformamide and BF 3 •Et 2 O with MeSO 2 Cl [14] [15] or POCl 3 [16], anhydrous ethyl formate and powdered sodium [17], acetic anhydride and sodium acetate [18] [19], acetic-formic anhydride [20], N-formylimidazole in anhydrous THF [21] and phenyliodine (III)bis (trifluoroacetate) [22] [23]. In the second route, isoflavones are synthesized by oxidative rearrangement of a chalcone using reagents like thallium(III)nitrate [24]- [29] and thallium(III)acetate [30]- [32].…”