61521-74-2Relevant articles and documents
Radical and superoxide scavenging activities of matairesinol and oxidized matairesinol
Yamauchi, Satoshi,Sugahara, Takuya,Nakashima, Yuki,Okada, Akihiro,Akiyama, Koichi,Kishida, Taro,Maruyama, Masashi,Masuda, Toshiya
, p. 1934 - 1940 (2008/02/08)
The radical and superoxide scavenging activities of oxidized matairesinols were examined. It could be assumed that the free benzylic position was important for higher radical scavenging activity. The different level of activity was observed between 7′-oxomatairesinol (Mat 2) and 7-oxomatairesinol (Mat 3). The activity of 8-hydroxymatairesinol was lower than that of matairesinol (Mat 1). The superoxide scavenging activity of the oxidized matairesinols was also demonstrated for the first time. It is assumed that the pKa value of phenol in the oxidized matairesinols affected this activity.
Enantioselective synthesis of (-)-wikstromol using a new approach via malic acid
Sefkow
, p. 2343 - 2349 (2007/10/03)
The total synthesis of (-)-wikstromol, a bioactive α-hydroxylated lactone lignan, from natural malic acid using a consecutive alkylation strategy is presented. First, alkylation of a malic acid ester provided the monobenzyl derivative, which was then converted to an α-substituted dioxolanone. This derivative was reacted in a second alkylation step to a double benzylated dioxolanone, which was transformed to bis-O-benzyl-protected (-)-wikstromol and subsequently to the natural product. Only six steps were required to produce wikstromol in 30% overall yield. A second approach from malic acid, the double alkylation of dienolates from 5-oxo-1,3-dioxolan-4-yl acetic acid derivatives, was not successful. No reaction conditions were found to afford the dienolates. Instead, rapid fragmentation of the dioxolanones to fumaric acid derivatives and pivalaldehyde occurred even at -105 °C, and aldol reaction products with good stereoselectivity were formed. The relative configuration of the major isomer was determined by X-ray structure analysis. By comparison of NMR data it is shown that a previous assignment of the configuration of one of the described aldol products was incorrect.
TOTAL SYNTHESES OF (-)-TRACHELOGENIN, (-)-NORTRACHELOGENIN AND (+)-WIKSTROMOL
Khamlach, Kenza,Dhal, Robert,Brown, Eric
, p. 2221 - 2224 (2007/10/02)
The title compounds were obtained by α-hydroxylation of the corresponding α,β-dibenzyl-γ-butyrolactones (lignans of synthetic origin), and were correlated to (+/-)-methyltrachelogenin 9 whose relative structure was definitely established by X-ray cristallography. (-)-Trachelogenin 1 and (-)-nortrachelogenin 12 thus have the (8S,8'S) absolute configuration, whereas (+)-nortrachelogenin 20 (or wikstromol) has the (8R,8'R) absolute configuration.
