Search results for " Magnetic resonance"

BACKGROUND PARENCHYMAL ENHANCEMENT IN RM E PRESENZA, DENSITA' MAMMOGRAFICA E RISCHIO DI CARCINOMA MAMMARIO

2018

Measurement ofj/?-decays into channels containing charged and neutral antinucleons

1981

Using the nonmagnetic BONANZA detector for the detection of antineutrons and antiprotons, we measured branching ratios of theJ/ψ into baryonic final states. Our measurements give the new results:\(BR\left( {{J \mathord{\left/ {\vphantom {J {\psi \to \overline {\Sigma ^ - } }}} \right. \kern-\nulldelimiterspace} {\psi \to \overline {\Sigma ^ - } }}\Sigma ^ - } \right) = \left( {0.24 \pm 0.26} \right)\% ;BR\left( {{J \mathord{\left/ {\vphantom {J {\psi \to }}} \right. \kern-\nulldelimiterspace} {\psi \to }}\bar nn\pi ^ + \pi ^ - } \right) = \left( {0.38 \pm 0.36} \right)\% \) and an independent test for the data of the magnetic detectors.

Synthesis and characterisation of N-glycosyl amines from the reaction between 4,6-O-benzylidene-D-glucopyranose and substituted aromatic amines and a…

2001

Twelve N-glycosyl amines were synthesised using 4,6-O–benzylidene-D-glucopyranose and different substituted aromatic amines, including some diamines that resulted in bis-glycosyl amines. Another set of six N–glycosyl amines was synthesised using different hexoses and pentoses and 2–(o–aminophenyl)benzimidazole. All compounds were isolated as solid products and purified, their elemental compositions were established, and these were characterised by NMR (1H and 13C), UV–Vis, and FTIR spectroscopy, by FAB mass spectrometry (molecular-ion peaks gave molecular weights), and by their optical rotations. While the protected saccharide, 4,6-O-benzylidene-D-glucopyranose, exists as a mixture of β and…

1H and13C NMR assignments and conformational analysis of some tetracyclic compounds with a bicyclo[4.2.0]octane ring system

1998

Chemical and Spectroscopical Properties of Medium Sizedtrans- andcis-Bicyclo[n.1.0]alk-2-ynes

1997

Chemical and spectroscopical properties of cis- and trans-cyclopropano-anellated cycloalkynes of medium ring size are investigated and compared with results from force field calculations. IR and 13C-NMR data of the alkynes reflect the deformation of the triple bond due to ring strain. Parallel to bending the reactivity increases with decreasing ring size, the trans fused alkynes prove to be nearly as reactive as the cis fused with a two carbon smaller ring size. The bicycloalkynes are complexed with silver triflate. 13C NMR reveals that the triple bond as well as the cyclopropane serve as ligands.

(8,9-Dihydro-7H-imidazo[1,2-c][1,3]diazepin-5-yl)-cyanamide und homologe imidazo-bizyklen

1984

Die Reaktion der 2-(ω-Aminoalkyl)-imidazole 4a-f mit N-Cyanodiphenyl-imidocarbonat (7) fuhrt zu den entsprechend hydrierten Imidazo[1,5-a]imidazolen, Imidazo[1,2-c][1,3]diazepinen und Imidazo[1,2-c][1,3]diazocinen (9a-f), die im Verhalten gegenuber Nucleophilen und in ihren spektroskopischen Eigenschaften den (7,8-Dihydro-imidazo[1,2-c]pyrimidin-5-yl)-cyanamiden (3) [1] vergleichbar sind. The reaction of the 2-(ω-aminoalkyl)imidazoles 4a-f with N-cyanodi-phenylimidocarbonate (7) leads to appropriately hydrogenated imidazo-[1,5-a]imidazoles, imidazo[1,2-c][1,3]diazepines and imidazo[1,2-c][1,3]diazocines (9a-f), which are similar to (7,8-dihydroimidazo)[1,2-c]pyrimidin-5-yl)cyanamides (3)[1]…

Cycloaddition reactions of 3-vinylthiophen

1987

Abstract Cycloaddition reactions between 3-vinylthiophen and the dienophiles maleic anhydride, methyl acrylate, dimethyl acetylene - dicarboxylate, and methyl propiolate give products including methyl benzo[b]thiophen-7-carboxylate (11) and its dihydroderivative (10), the 6,7-dicarboxylic acid (3), its dimethyl ester (7) and dihydroester (6); the naphtho[a,b]dithiophen (14), and the novel ethano bridged benzo[b]thiophen (15).

Cyclische chirale triarylborane mit einer B←N-Bindung

1985

Abstract The reaction of ortho-lithiated N,N-dimethyl-1-arylethyl-amines with triphenyl- boron leads, with elimination of phenyllithium, to (R)-(−)-2,2,3-trimethyl-1,1-diphenyl -1H-2-azonia-1-borata-indene (1), 2,3-dihydro-1,1,2-trimethyl-3,3-diphenyl- 1H-2-azonia-3-borata-benz[e]indene (2) and 2,3-dihydro-2,2,3-trimethyl-1,1-diphenyl -1H-2-azonia-1-borata-benz[e]indene (3) with a strongB←N bond. 1, 2 and 3 are stable against oxygen, water and alcohols. Triarylboron compounds sensitive to the same reagents are formed by the reaction of triphenylboron with some aryllithium compounds substituted with electron-donating groups.

Facile synthesis of 5β-cholane-sym-triazine conjugates starting from metformin and bile acid methyl esters: Liquid and solid state NMR characterizati…

2009

Abstract Four bile acid-triazine conjugates: N2′,N2′-dimethyl-6′-(3α-hydroxy-5β-24-norcholyl)-1′,3′,5′-triazine-2′,4′-diamine (lithocholyl triazine, 4a), N2′,N2′-dimethyl-6′-(3α,7α-dihydroxy-5β-24-norcholyl)-1′,3′,5′-triazine-2′,4′-diamine (chenodeoxycholyl triazine, 4b), N2′,N2′-dimethyl-6′6′-(3α,12α-dihydroxy-5β-24-norcholyl)-1′,3′,5′-triazine-2′,4′-diamine (deoxycholyl triazine) (4c), and N2′,N2′-dimethyl-6′-(3α,7α,12α-trihydroxy-5β-24-norcholyl)-1′,3′,5′-triazine-2′,4′-diamine (cholyl triazine) (4d) have been prepared and characterized by liquid and solid state NMR. An improved synthetic method produced better yields and an easier purification procedure for 4d than reported in the liter…

Solid state structural studies of five bile acid derivatives

2008

Five synthetically important bile acid derivatives have been characterized by 13 C CP-MAS, X-ray diffraction (both single crystal and powder), FTIR, and thermoanalytical (DSC and TG) methods. The crystallinity of all these derivatives is high, which can be deducted from the 13 C CP-MAS and powder X-ray diffraction data. Two of the compounds showed polymorphism, and one polymorph was structurally elucidated for both by comparing single crystal and powder X-ray diffraction data.