Bidens species

From Bidens species 5-metbyl 5 -butadienyl-2 -bithienyl (245) has been isolated, the constitution of which was eonfirmed synthetically. Another 2,2 -bithienyl derivative has been isolated as an additional nematodicidal principal of the roots of Tagetes, for which strueture (246) has been suggested. On the other hand Sorensen et aL have isolated from the thistles, Berkheya macrocepkala and Echinops spareocephalm, a compound with very similar UV and IR spectra as (246) for which they suggested structure (247), based on... 

Another antiviral species from the Anthemideae tribe is Bidens pilosa L. var. minor (Blume) Sherff which significantly inhibited the replication of HSV-1 at a concentration of 100 jig/ml [58]. The ethanol extract of Bidens pilosa L. also showed a broad spectrum of antibacterial activity [59]. From another Bidens species, Bidens cernua L., a new complex antibiotic preparation known as cerbiden was obtained [60]. 

Callus cultures of Bidens pilosa which normally produce no acetylenic compounds could be induced to do so by addition of culture filtrate from the fungus Pythium aphanider-matum cultures of this and other Bidens species that had been transformed with the Ti plasmid of Agrobacterium tu-mefaciens produced a root type profile of acetylenes (Ellis, 1988). Hairy root cultures of Ambrosia, Bidens, and Tagetes have similar content of acetylenes as those of normal plant roots (Flores et al., 1987, 1988). 

The test seeds used for the bioassays were Mimosa pudica, Achyranthes aspera, Bidens pilosa, and Crusea calocephala (herbaceous species) Ochroma lagopus and Heliocarpus donell-smithil (arboreal species). 

Spanish needles have also been found to have anti-allergy action at the level of mast cells and other allergy mediators.4 Spanish needles contains quercetin and ethyl caffeate, both of which have previously been shown to possess in vitro anti-inflammatory or anti-allergic mediator action.23,24 Quercetin5 has also been shown to stabilize mast cells and basophils, decrease leukotriene formation, and reduce release of histamine and other mediators.24,25 Anti-inflammatory effects have been demonstrated in rats after receiving aqueous extracts of Spanish needles leaves and stems.26,27 A related species, Bidens parviflora, has been reported to inhibit histamine release from rat mast cells in vitro.6 Spanish needles have been shown to inhibit the inflammatory mediator nuclear transcription factor kappaB (NF-kappaB) and its downstream inflammatory mediators in vitro.23... 

The arylacetylene phenylheptatriyne (Phe—C=C—C=C—C=C—CH 3) from Bidens, Dahlia and Coreopsis species (Asteraceae) has phototoxic antimicrobial activity as have 5-(3-buten-l-ynyl)-2,2 -bithienyl (thiophene—thiophene—C=C—C=CH2) and the cyclic disulfide acetylenes thiarubrine A (C3—(C4,S—S)—C6) and thiarubrine B (Cj-(C4,S-S)-C3). The photoactivation of acetylenes derives from light absorption by these conjugated systems and ready reaction with oxygen to form reactive intermediates. 

Based on the metal-differentiating coordination concept, proline-derived biden-tate amidophosphines 23-25 were developed. The carbonyl oxygen and phosphorus atoms of the ligand selectively coordinate to lithium and copper atoms of an organocopper species, which discriminate the reaction face of the complex as shown in 26. The reaction of dimethylcopper lithium with chalcone gave the adduct in 84% ee [52]. Enantioselectivity was later improved to 90% with the more bulky amidophosphine 25 based on the model 26 (Eq. (12.26)) [53]. 

Kormer, Lobach and others were the first to suggest an alternative process which assigned a dominant role to allyl isomerization. In this mechanism the process begins with biden-tate coordination, followed by formation of an allyl complex. If this allyl complex has a sufficient lifetime, it will isomerize from the less stable, initially formed, anti allyl 3 to the more stable syn species, 4. As shown below, leads to trans polymer. On the other hand the propagation steps, which include coordination of diene and formation of the next bond in the chain, could be the fast steps. Pol)rmer with a cis backbone would then be the result. 

Many palladacycles, besides those derived from bidenate phosphines, are available for catalyzing organic reactions. These varieties include 0,N-, N,N-, N,C-, P,N-, f C-ligated. species. In the following, a selection of palladacycle catalysts bearing such as well as more exotic bidentate diphosphines are presented. 

The number of bonds that the central ion forms with electron-donor species is designated as its coordination number (x-bonds are not considered in determining the coordination number). In turn, depending on the number of bonds that a single ligand particle forms, they are classified as uni- or monodentate, biden-tate, and so on, ligands. Ligands, bound with the central particle by coordination bonds, constitute an inner coordination sphere. 

The 2-hydroxy-6-methylacetophenone was isolated as exocrine compound in several neotropical species of ants in the dolichoderine genus Hypoclinea (Hypoclinea analis, Hypoclinea abrupta, Hypoclinea bidens A). The ants were collected in Belem, Para, Brazil [2641,2650]. It was also isolated from the bodies of Rhytidoponem aciculata (Australian ponerine ant) [2651,2652]. 

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