Sophora compound

If the precursor dienes have vinyl end-groups, ethene is eliminated in the metathesis reaction, but it is sometimes advantageous to use a precursor with one or two propenyl end-groups, eliminating propene or but-2-ene in the metathesis reaction. An example is shown in equation 31, the final stage in the synthesis of the protected precursor (42) of Sophora compound I, the antifungal phytoalexine isolated from the aerial part of Sophora tomentosa L228. 

The yields from aldehyde alkylidenation is somewhat lower due to the reductive dimerization of aldehydes with low-valent Ti. Alkylidenation of esters is possible by the reaction of 1,1 -dibromoalkane. TiCU and Zn in the presence of TMEDA to give (Z) vinyl ethers [60], Cyclic vinyl ethers are prepared from unsaturated esters in two steps. The first step is formation of the acyclic enol ethers using a stoichiometric amount of the Ti reagent, and the second step is ring-closing alkene metathesis catalysed by Mo complex 19. Thus the benzofiiran moiety of sophora compound I (199, R = H) was synthesized by the carbonyl alkenation of ester in 197 with the Ti reagent prepared in situ, and the subsequent catalytic RCM of the resulting enol ether 198 catalysed by 19 [61]. 

The direct method using ene-ene RCM to construct aromatic rings has also been used for the synthesis of benzofurans and indoles. In a paper on the synthesis of cyclic enol ethers by RCM, Fujimura et al. reported that benzofurans 27 could be prepared from dienes 26 by RCM using Schrock s catalyst 4 (Scheme 26.7) [14]. This group applied the method to obtain the naturally occurring antifungal phytoalexine, known as Sophora compound I (30). On the other hand, Arisawa et al. synthesized indoles... 

Masayoshi, O. et al.. Phenolic compounds isolated from the roots of Sophora stenophylla, Chem. Pharm. Bull., 46, 663, 1998. 

We have so far isolated only one triprenylated chalcone, sophoradin (54) from the organic extract of the aerial parts of D. involuta. This compound was previously reported in the roots of Sophora subprostrata [47]. 

Anabasine (3-(2-piperidinyl)-pyridine) from Mcotiana and Duboisia species (Solanaceae) is an nACh-R agonist used to discourage tobacco smoking as is the JV-methylated tricyclic piperidine (—)-lobeline from Lobelia species (Campanulaceae). Lobeline-related compounds from Lobelia species include the bicyclic jV methyltetrahydropyridines isolobinine and lobinine and the tricyclic jV-methylpiperidines lobelanine and lobelanidine. Anabasine-related compounds include anatabine (2-(3-pyridyl)-l,2,3,6-tetrahydropyridine) from M tabacum and (+)-ammodendrine (jV-acetyltetrahydroanabasine) from Ammodendron and Sophora species (Fabaceae). 

Another six novel flavonostilbenes, alopecurones A-F (782-787), were isolated from the roots of Sophora alopecuroides. Their structures are composed of a flavanone condensed with a resveratrol (1). Absolute configurations of alopecurones A-F (782-787) were determined by means of CD compared with model compounds [342]. 

Fig. 13 Two glucosidic isoflavones of daidzin (30) and genistin (31) from Sophorae fructus and related compounds...

Fig. 15 Prenylflavanones (10, 69-77) from Sophora plants and its related compounds...

From the roots of Sophora flavescens collected in Taiwan, four new prenylflavonoids, sophoraflavanone K (94), sophoraflavanone L (95), 8-lavandulylkaempferol (96), and cyclokuraridin (97), a new arylbenzofuran, 2-(2,4-dihydroxy-5-prenylphenyl)-5,6-methylenedioxybenzofuran (98), and a new prenyldibenzoyl derivative of sophoradione (99), were isolated. The structures of these six compounds were determined by spectroscopic data analysis. The new compounds (95-99) had cytotoxic activity against the KB epidermoid carcinoma cell line (Fig. 20) [19]. 

Fig. 20 Phenolic compounds and their cytotoxic activity from Sophora flavescens...

As part of the series Topics in Heterocyclic chemistry, this volume titled Bioactive Heterocycles II presents comprehensive and up-to-date reviews on selected topics concerning mainly the usefulness for human health of flavonoids and related compounds, Sophora flavonoids and their functions in Sophora species (Leguminosae), the relationship of biological activity with the diverse structures of heterocycles by quantum chemical calculation, advances in bioactive mesoionic heterocycles, and the spectroscopic properties and application of bioactive phenothiazines including also benzo[a]phenothiazines. 

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