Radical polymerization of dialkyl muconates (dialkyl 2,4-hexadienoates) was investigated in an isotropic (amorphous) state, that is, solution or bulk polymerization, and in a crystalline state. In the bulk polymerization at 120 °C in the presence of a radical initiator, high molecular weight polymers of more than 105 were obtained in high yields, compared with those in solution polymerization. Three kinds of isomers, cis,cis-, cis,trans-, and trans,trans-muconates, showed similar polymerization reactivities. The microstructure in the polymers was determined by 1H and 13C NMR spectroscopies to be 84−91%, 6−13%, and 2−4% for trans-1,4-, cis-1,4-, and 1,2-structures, respectively, which depended on the polymerization temperature. In contrast with the bulk (in the melt) and solution polymerizations, we discovered that diethyl cis,cis-muconate underwent highly stereospecific polymerization in a crystalline state under UV irradiation via a topochemical polymerization mechanism. The resulting polymer was of ultrahigh molecular weight ([η]) = 103 cm3/g) with high stereoregularity and crystallinity. This polymer has been clarified to be a tritactic polymer, trans-1,4-meso-diisotactic or trans-1,4-meso-disyndiotactic polymer.
This article is available online at http://dmd.aspetjournals.org ABSTRACT:Rosuvastatin is a new 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor. The liver is the target organ for the lipid-regulating effect of rosuvastatin; therefore liver-selective uptake of this drug is a desirable property. The aim of this study was to investigate, and compare with pravastatin and simvastatin, the tissuespecific distribution of rosuvastatin. Bolus intravenous doses (5 mg/kg) of radiolabeled rosuvastatin, pravastatin, and simvastatin were administered to rats, and initial uptake clearance (CL uptake ) in various tissues was calculated. Hepatic CL uptake of rosuvastatin (0.885 ml/min/g tissue) was significantly (p < 0.001) larger than that of pravastatin (0.703 ml/min/g tissue), and rosuvastatin was taken up by the hepatic cells more selectively and efficiently than pravastatin. Hepatic CL uptake of simvastatin (1.24 ml/min/g tissue) was significantly larger than that of rosuvastatin (p < 0.01) and pravastatin (p < 0.001). However, adrenal CL uptake of simvastatin (1.55 ml/min/g tissue) was larger than hepatic CL uptake , and simvastatin was distributed to other tissues more easily than rosuvastatin. Microautoradiography of the liver, spleen, and adrenal was undertaken 5 min after administration of the study drugs; distribution was quantified by counting the number of silver grains. After administration of rosuvastatin and pravastatin, silver grains were distributed selectively in the intracellular space of the liver, but more rosuvastatin (3.3 ؎ 1.0 ؋ 10 5 particles/mm 2 ) than pravastatin (2.0 ؎ 0.3 ؋ 10 5 particles/mm 2 ) tended to distribute to the liver.Simvastatin was less liver-specific (it also distributed to the spleen and adrenal). The results of this study indicated that rosuvastatin was taken up by hepatic cells more selectively and more efficiently than pravastatin and simvastatin.
On exposure to UV light a crystal of diethyl (Z,Z)-hexa-2,4-dienedioate yielded an ultra-high molecular mass, highly stereoregular polymer, which was shown to have a tritactic structure by 1% NMR spectroscopy.
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