The rhodium-catalyzed, terminal-selective borylation of alkanes has been used to modify polyolefins. The functionalization of two materials, polyethylethylene (PEE) of molecular weights 1200 and 37 000, was conducted by combining bis-pinacoldiboron and 2.5 mol % [Cp*RhCl2]2 in neat polymer and heating at 150 degrees C. This procedure causes the polymer and boron reagent to melt, the catalyst to dissolve, and the reaction to form material with boryl groups at the terminal position of the polymer side chains. Oxidation of the borylated material generated polymers with hydroxyl groups at the terminal position of the side chains. The functionalization was conducted at various ratios of boron reagent to monomer. The resulting borylated and subsequent hydoxylated materials were characterized by 1H and 13C NMR spectroscopy, as well as MALDI-MS and GPC. Little change in polymer molecular weight and polydispersity was observed, and these data indicate that scission of the main chain does not occur. Measurements of the Tg of the polymers showed in increase in Tg of up to 50 degrees C after the modification. Thus, homogeneous, catalytic, selective alkane functionalization can be used to modify polymer properties.
B r cafEt3B/Bu3SnH MeLi P h y SiMe, t -5%(€/2=28/72) ATPH: 70% (W= 54 I' 46) with ATPH under otherwise identical reaction conditions gave rise to 9 in 70 % yield, again demonstrating the ability of ATPH as an efficient template to facilitate the cyclization step. Experimental Sect ionRadical cyclization of 1 in the presence of ATPH: A solution of 2,6-diphenylphenol (740 mg, 3 mmol) in toluene (5 mL) was degassed and a 2M hexane solution of Me,AI (0 5 mL, 1 mmol) was added at room temperature under argon. The slightly yellow solution was stirred for 30 min. After the solution had been cooled to -78% 1 (143 mg, 0.5 mmol) in toluene (1 mL) was added and then Bu,SnH (200 pL, 0.75 mmol) and Et,B (100 pL, 0 1 mmol) were introduced sequentially. The solution was stirred at -78 'C for 1 hand then poured into an aqueous saturated solution of NaHCO,. After extraction with ether, the combined ethereal extracts were dried over Na,SO,. Evaporation of solvents and purification of the residual oil by column chromatography on silica gel (ether/dichloromethane/hexane 1/2/16 as eluant) gave the cyclic ether 2 (79.6 mg, 0.496 mmol) as a colorless oil (99 YO yield, EiZ= 14:86): 'H NMR (300MHz. CDCI,, 20°C. TMS): b =7.10-7.40 (5H, m, Ph). 6.45 and 6.37 (1 H, m, CH=C for 2 and E isomer, respectively), 4.58 and 4.46 (2H, m, C=CCH,-0 for 2 and E isomer, respectively). 4.01 and 3.90 (2H, t, J = 6.9 Hz. CH,-O for E and Z isomer. respectively), 2.73-2.86 (2H, m, CH,).
Patients with chronic kidney disease often develop secondary hyperparathyroidism (SHPT), marked by high levels of circulating parathyroid hormone (PTH) and increased risk of morbidity and mortality. Patients with SHPT are treated with a therapeutic combination that commonly includes calcimimetics, which have recently become popular in clinical settings, and other agents such as vitamin D preparations. Calcimimetics are a drug class that reduces PTH levels by targeting the calcium-sensing receptor. Cinacalcet, a representative calcimimetic, is widely used; however, a high incidence of upper gastrointestinal
A 14-year-old female with ulcerative colitis developed right anterior cervical pain and high fever. Cervical contrast-enhanced computed tomography (CE-CT) showed a wall thickness of the right common carotid artery which suggested aortitis. Her pulmonary angiography demonstrated a narrowing of the pulmonary arteries and she was diagnosed as having Takayasu's disease associated with ulcerative colitis. HLA analysis showed Bw52 and DR2 haplotype, which is frequently found in patients with Takayasu's disease associated with ulcerative colitis.
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