Stilben trans

The transition in the UV spectrum of trans stilbene trans C6H5CH=CHCgH5)... 

Stereoselectivity is also observed in the oxidation of stilbens with the zeolite-entrapped t-butyl substituted FePc catalyst. With the cis-stilben as substrate the ratio of trans to cis product (trans-stilben is produced via the epoxidation of cis-stilben)is remarkably higher for FePc(t-Bu)4/NaY, compared with those for FePc(t-Bu)4+NaY and even for FePc/NaY and FePc+NaY samples under the similar conditions, as shown in Table 2. It was found that the stereoselectivities toward trans-products (trans-stilben + trans-stilben oxide) kept remained(48-53% sel) for the different conversions of cis-stilben. The... 

With stilbene and azobenzene there are two isomers. In these cases a plane structure is realized for the //mf-isomers, in contrast to the cis forms where this is impossible on spatial grounds. The stability of the trans forms is a consequence of the extra resonance (extra R.E. /z -stilbene 7.0 kcal energy content of frmy-azobenzene 10 kcal lower than the cis form). This resonance also appears from the distances, stilbene, trans C—C 1.445 A, C=C 1.33 A azobenzene, trans C—N 1.415 A, cis C—N 1.46 A (sum of atomic distances 1.54 A and 1.47 A, respectively) in this latter compound the planes of the rings make an angle of 50°. 

Starting Olefin trans-Stilbene trans-Stilbene °C acetone -78 acetophenone 0 1, 4-Trioxolane 3,3-dimethyl- 5-phenyl 3-methyl-3,5- diphenyl Formula C10H12O C15H14O ... 

SYNS trans-p-(DIMETHYLAMINO)STILBENE trans-4-DIMETHYLAMINOSTILBENE 4-DIMETHYLAMINO-trans-STILBENE (E)-N,N,-DIMETHYL-4-(2-PHENYL-ETHENYL)BENZENAMINE trans-NN-DIMETHYL-4-STILBENAMINE... 

The synthesis of 4,5-dicyano-l,2,3-trithiole 2-oxide (172) starts from sodium cyanide and carbon disulfide which via (170) gave the disodium salt of 2,3-mercaptomaleonitrile (171 M = Na). Treatment of the corresponding silver salt (171 M = Ag) with thionyl chloride yielded (172) (66HC(2l-l)l). Phenylsulfine (174), prepared in situ by dehy-drohalogenation of phenylmethanesulfinyl chloride (173), slowly decomposed in ether solution at room temperature to give cis- and trans-stilbenes, trans-4,5-diphenyl-l,2,3-trithiolane 1,1-dioxide (36) and a 5,6-diphenyl-1,2,3,4-tetrathiane dioxide (68JCS(C)1612). The mechanisms of formation of these heterocycles are obscure. 

Hexene c-Hexene Vinyl-cyclohexane Styrene c/s-Stilbene trans-Stilbene Phenylacetylene 1-Phenylpropyne l-Phenylpropyne "... 

Potassium hypochlorite bleach mfg., optical cis-Stilbene trans-Stilbene bleach, latex prod. o-Thiocresol bleach, liq. 

Sodium benzoate Sodium chloride cis-Stilbene trans-Stilbene Succinic acid Toluene m-Toluidine Triethylenetetramine 1,3,5-Trihydroxybenzene 2,4,5-Trimethylaniline... 

Cadmium iodide Calcium fluoride Calcium molybdate Calcium sulfide Cerium oxide Copper oxide (ic) Germanium cis-Stilbene trans-Stilbene Zinc phosphate phosphors, color TV tubes Yttrium oxide phosphors, lamp... 

Methyl 3-phenylpropionate 203-093-8 Methyl cinnamate 203-095-9 Benzyl isobutyrate 203-096-4 Di benzyl 203-098-5 Eccobrite RB Eccobrite RB-6 Stilbene trans-Stilbene Tinopal UNPA-GX 203-104-6 Ethyl cinnamate 203-105-1 Benzyl butyrate 203-106-7 Benzyl isovalerate 203-109-3 Benzyl cinnamate 203-113-5... 

The name for stilbene (1,2-diphenylethylene) was derived from the Greek word stilbos, which means shining. There are two isomeric forms of 1,2-diphenylethylene ( )-stilbene (trans-stilbene), which is not sterically hindered, and (Z)-stilbene (cis-stilbene), which is sterically hindered and therefore less stable. 

Antibodies to the donor-acceptor-substituted stilbene trans-4-N,N-dimethyl-amino-4 -cyanostilbene (DCS) and other donor-acceptor-substituted stilbenes were... 

The fluorescence-photochrome technique was first applied to study the molecular dynamics of a stilbene fiuorescence-photochrome molecule, SITC, attached covalently to the terminal amino group of sperm whale myoglobin [18]. The same myoglobin residue was also labeled with a spin label, 4-iodoacetamide-TEMPO. The kinetics of the stilbene trans-cis photoisomerization (k pp) and the rotational diffusion frequency of nitroxide radicals (v ) was monitored by fiuorescence and E S R... 

CClsOO reacts with phenols forming phenoxyl radicals (Neta et al. 1989, Alfassi et al. 1993). The reactions of CCI3OO with fra s-3,5,4 -trihydroxy-stilbene (trans-resveratrol) and its analogues showed that the p ra-hydroxyl group of trans-resveratrol scavenges free radicals more effectively than its meta-hydroxyl groups (Stojanovic et al. 2001). 

Dehalogenation of vicinal polyhalides with nickel was then investigated to establish that the second step in Equation 7.11 proceeds as shown. 1,2-Dibromo-l,2-diphenylethane (meso) reacted with metallic nickel at room temperature to yield stilbene trans) in 89% yield and a trace amount of cw-stilbene. Similarly, ethyl 2,3-dibromo-3-(4-nitrophenyl)propanoate (erythro) underwent debromination to give ethyl 4-nitrocinnamate (tram) in 76% yield. Dechlorination of l,2-diphenyl-l,l,2,2-tetrachloroethane at 85 C afforded 1,2-dichloro-l,2-diphenylethene (97%, cis trans = 70/30). 

The hydroxylation of trans-stilbene, trans-a,g-diphenylethylene, was studied in rabbits and guinea pigs after i.m. administration. The metabolites found in the urine of both species were 4-hydroxy-, 4,4 -dihydroxy-, 4-hydroxy-3-methoxy-, md 3-hydroxy-4-methoxy-stilbene and their unspecified conjugates. When rabbits were given 4-hydroxystilbene, the 4,4 -dihydroxy compound was found in the urine. The reduction product, 4,4 -dihydroxybibenzyl, was also found in rabbit urine. 

The stilbene trans-resveratrol is also synthesized by condensation of p-coumaroyl CoA with three units of malonyl CoA, each of which donates two carbon atoms, in a reaction catalysed by stilbene synthase. The same substrate yields naringenin-chalcone, the immediate precursor of flavonoids, when catalysed by CHS (Figure 1.16). Stilbene synthase and CHS have been shown to be structurally very similar and it is believed that both are members of a family of polyketide enzymes (Soleas etal. 1997). CHS is constitutively present in tissues whereas stilbene synthase is induced by a range of stresses including UV radiation, trauma and infection. 

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