Polymer nanoparticles containing 2,4,6-triiodophenol: a potential contrast medium for medical imaging.

Contrast agents have been utilized for x-ray imaging to visualize blood vessels. Triiodobenzene derivatives are known contrast agents yet have not been formulated in a nanoparticle form for the purpose of enhancing the contrast of cancer tissues. In this study, experiments to encapsulate 2,4,6-triiodophenol in a polymer matrix were designed.

Stereocomplex Formation of Densely Grafted Brush Polymers.

In this report, we explore the capability of macromolecules to interdigitate into densely grafted molecular brush copolymers. We demonstrate that by using the tendency for stereocomplexation between poly(l-lactide) and poly(d-lactide) as a driving force complementary linear polymers and brush copolymers can form a stereocomplex. However, stereocomplex formation between complementary brush copolymers is restricted and only partially observed when the side chains are of a critical molecular weight.

Wittig reactions in water media employing stabilized ylides with aldehydes. Synthesis of alpha,beta-unsaturated esters from mixing aldehydes, alpha-bromoesters, and Ph3P in aqueous NaHCO3.

Water is demonstrated to be an effective medium for the Wittig reaction over a wide range of stabilized ylides and aldehydes. Despite sometimes poor solubility of the reactants, good chemical yields normally ranging from 80 to 98% and high E-selectivities (up to 99%) are achieved, and the rate of the reactions in water is unexpectedly accelerated. The efficiency of water as a medium in the Wittig reaction is compared to conventional organic solvents ranging from carbon tetrachloride to methanol.

Direct copper(I) iodide dimethyl sulfide catalyzed conjugate addition of alkenyl groups from vinylzirconocene reagents.

[reaction: see text] CuI.0.75DMS complex is an excellent catalyst for the direct conjugate addition of alkenyl groups from vinylzirconocene reagents to alpha,beta-unsaturated aldehydes and ketones.