Stilbene-labeled ether

Phase separation of polystyrene/poly(vinyl methyl ether) blends was induced under spatially and temporally periodic forcing conditions by taking advantage of either photodimerization of anthracene or photoisomerization of /rt//i .9 stilbene chemically labeled on polystyrene chains. Significant mode election processes driven by these reactions were experimentally observed and analyzed for both cases. These experimental results reveal a potential method of morphology control using periodic forcing conditions. 

Samples used in this work are the mixtures of poly (vinyl methyl ether) (PVME, 1.0 X 105, M = 2.5) and polystyrene (PS) derivatives. To be able to induce phase separation by light, the PS component was chemically labeled with photoreactive groups, either with anthracene (A) or rra/i -stilbene (S). The synthesis procedure of these polymers was published elsewhere (8,16). 

When appreciable concentrations of carbonyl compounds are present before complete formation of ozonide, crossed ozonides are formed. This occurs when the added carbonyl compound traps the zwitterion formed in the cleavage step. When c -stilbene is subjected to ozonolysis in the presence of 0-labeled benzal-dehyde, the label is incorporated into the ether rather than the peroxide portion of the ozonide ... 

Kung and coworkers have described preparation of F-labeled stilbenes as PET imaging agents for detecting /3-amyloid plaques in the brain. The authors used di-t-butyldichlorosilane to protect 2-hydroxypropyl-l,3-diol that was subsequently converted to the bromide 49. Alkylation of phenol 48 with the bromide 49 provided the ether 50 that was transformed into the desired F-labeled stilbene (eq 19). ... 

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