Abstract:Die beiden noch unbekannten Stereoisomeren der Dibenzylidenbernsteinslure (5) wurden in hoher Ausbeute durch oxidative Kupplung von truns-2-Chlormercurio-3-phenylpropensaure (3) mit LizPdCI4/CuCl* dargestellt. Einen unabhangigen Weg zu allen drei Isomeren eroffnete die oxidative Dimerisierung von a-lithiiertem Lithiumcinnamat mit Eisen(II1)-chlorid. Die Fulgensiiuren 5 wurdcn in die zugehorigen Dimethyl-(8) und Dibenzylester (9). Diole 10 und Fulgide 11 iibergefuhrt, deren Konfiguration sich spektroskopisch zw… Show more
“…It was also noted that the methylene protons of the ethyl groups of the 2,3-dibenzylidenesuccinate 2 appeared to be nonidentical (diastereotopic) in the NMR spectrum. It was concluded, as had been noted previously, − that 2,3-dibenzylidenesuccinates, such as 2 , have a barrier to rotation about the central single bond and that they exist at room temperature as an equilibrium mixture of the two enatiomeric atropisomers (Scheme ). 3 Atropisomeric Forms of Dibenzylidenesuccinates…”
A short, efficient synthesis of the lignan (+)-lyoniresinol dimethyl ether is described. The synthesis is achieved by asymmetric photocyclization of an achiral dibenzylidenesuccinate to a chiral aryldihydronaphthalene. (-)-Ephedrine is used as a chiral auxiliary to bias the atropisomeric equilibrium in the dibenzylidenesuccinate prior to the photochemical reaction. The synthesis of the title compound was accomplished in five steps, and the final product was recrystallized to constant melting point and rotation.
“…It was also noted that the methylene protons of the ethyl groups of the 2,3-dibenzylidenesuccinate 2 appeared to be nonidentical (diastereotopic) in the NMR spectrum. It was concluded, as had been noted previously, − that 2,3-dibenzylidenesuccinates, such as 2 , have a barrier to rotation about the central single bond and that they exist at room temperature as an equilibrium mixture of the two enatiomeric atropisomers (Scheme ). 3 Atropisomeric Forms of Dibenzylidenesuccinates…”
A short, efficient synthesis of the lignan (+)-lyoniresinol dimethyl ether is described. The synthesis is achieved by asymmetric photocyclization of an achiral dibenzylidenesuccinate to a chiral aryldihydronaphthalene. (-)-Ephedrine is used as a chiral auxiliary to bias the atropisomeric equilibrium in the dibenzylidenesuccinate prior to the photochemical reaction. The synthesis of the title compound was accomplished in five steps, and the final product was recrystallized to constant melting point and rotation.
“…207 Ko ¨brich et al synthesized bisbenzylidenefulgide 1 by Pd-catalyzed dimerization reaction of organomercury compound, and by oxidative dimerization of 2-lithiocinnamic acid catalyzed by FeCl 3 (Scheme 8). 208…”
“…This was supported by the HMBC correlations between OMe-4′ (δ H 3.74)/C-4′ (δ C 159.1) and OMe-4′′′ (δ H 3.74)/C-4′′′ (δ C 159.1) of 2 , and by the NOESY correlations between OMe-4′ (δ H 3.74)/H-3′ (δ H 6.92), OMe-4′ (δ H 3.74)/H-5′ (δ H 6.92), H-3 (δ H 6.95)/H-2 (δ H 7.49), H-3 (δ H 6.95)/H-7′ (δ H 4.98), H-3′′ (δ H 6.95)/H-2′′ (δ H 7.49), and H-3′′ (δ H 6.95)/H-7′′′ (δ H 4.98) of 2 . Compound 2 showed the similar UV absorption [265 nm] and the similar chemical shift [δ 7.71] of H-7 and H-7′′ when compared to the analogous (2 E ,3 E )-2,3-bis(4-(benzyloxy)benzylidene)succinic acid [ 11 ], and the (2 E ,3 E )-configuration of 2 was thus established. On the basis of the above data, the structure of 2 was elucidated as (2 E ,3 E )-2,3-bis(4-(4′-methoxybenzyloxy)benzylidene)succinic acid and named inermidioic acid.…”
Three new benzenoid derivatives, lawsoinermone (1), inermidioic acid (2), and inermic acid (3) have been isolated from the aerial part of Lawsonia inermis, together with 11 known compounds (4–14). The structures of three new compounds were determined through spectroscopic and MS analyses. Compounds 1, 4–6, 13 and 14 were evaluated for inhibition of nitric oxide production in LPS-stimulated product of nitrite in RAW 264.7 cells with IC50 values of 6.12, 16.43, 18.98, 9.30, 9.30 and 14.90 μg/mL, respectively.
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