نتایج جستجو برای: samarium
تعداد نتایج: 1033 فیلتر نتایج به سال:
Samarium(II)-promoted cyclizations of N-acylated indolyl sulfinyl imines without electron-withdrawing groups at C-3 furnished tertiary carbinamines in good yield. Screening the reaction conditions revealed that application an excess samarium diiodide presence water and lithium bromide provided cleanest reactions highest yields. The most striking observation during this investigation was reducti...
A highly enantioselective, quinone Diels-Alder reaction catalyzed by chiral samarium and gadolinium pyridyl-bis(oxazoline) (pybox) complexes has been developed. The reaction scope has been extended to include three quinones and five dienes, all of which exclusively provide the expected endo product in excellent yields and enantioselectivities.
Photodarkening in samarium doped germanosilicate fiber and laser by downconversion is studied. Appreciable photodarkening occurs in the fiber and we attribute the effect to color centres which are both related to Sm2O3 and GeO2. An energy level scheme has been illustrated to explain the photodarkening mechanism.
A flexible diastereoselective approach to trans-(3S)-hydroxyprolinol derivatives is described, which is based on the samarium diiodide-mediated reductive coupling of the chiral 1-pyrroline N-oxide (nitrone)(S)-10 with carbonyl compounds. The reductive hydroxyalkylation of nitrone 10 with ketones and aromatic aldehydes is highly diastereoselective in establishing the C-2 chiral center of the pyr...
We investigated the adsorption and reaction of methanol on continuous and discontinuous films of samarium oxide (SmOx) grown on Pt(111) in ultrahigh vacuum. The methanol decomposition was studied by temperature programmed desorption (TPD) and infrared reflection absorption spectroscopy (IRRAS), while structural changes of the oxide surface were monitored by low-energy electron diffraction (LEED...
OBJECTIVES The aim of the present study was to investigate the effectiveness of Samarium(153)-particulate hydroxyapatite radiation synovectomy in rheumatoid arthritis patients with chronic knee synovitis. METHODS Fifty-eight rheumatoid arthritis patients (60 knees) with chronic knee synovitis participated in a controlled double-blinded trial. Patients were randomized to receive either an intr...
OS Radium-223 (Xofigo, Bayer and Algeta) is a boneseeking radiopharmaceutical that patients receive via injection. It is approved by the US Food and Drug Administration (FDA) to relieve pain and prolong survival in patients with metastatic castration-resistant prostate cancer (mCRPC) who have symptomatic evidence of bone metastasis. Because radium-223 selectively targets bone, it is not indicat...
By the synergistic catalysis of samarium ion and mercaptan, a series of 5-oxoalkanals was converted to (substituted) delta-lactones in efficient and stereoselective manners. This one-pot procedure comprises a sequence of acetalization, Tishchenko reaction and lactonization. The deliberative use of mercaptan, by comparison with alcohol, is advantageous to facilitate the catalytic cycle. The reac...
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