Search results for "Nuclear Magnetic Resonance Spectroscopy"
showing 10 items of 843 documents
Antikonvulsiva, 1. Mitt. Thiocarbamoylbutyroguanamine
1986
Durch Anlagerung von Butyroguanamin (1) an die Isothiocyanate 2a-c sind die Thiocarbamoylbutyroguanamine 3a-c zuganglich. Auf dem Wege der Acylierung von 3 sind unsymmetrisch substituierte Butyroguanamine 4 erhaltlich. Unter den neu entwickelten Verbindungen zeichnet sich insbesondere 3c durch antikonvulsive, fungizide und die Magensauresekretion hemmende Wirkungen aus. Anticonvulsivic Agents, I: Thiocarbamoylbutyroguanamines The thiocarbamoylbutyroguanamines 3a-c are accessible by addition of butyroguanamine (1) to the isothiocyanates 2a-c. Unsymmetrically substituted butyroguanamines 4 are obtainable by acylation of 3. Among the newly prepared compounds, 3c in particular exhibits anticonv…
The identification of vicinally substituted cyclohexane isomers in their mixtures by 1H and 13C NMR spectroscopy.
2000
The radical addition reactions of organobromine compounds, XBr (X = CH2COOMe, PhCH2, CHBr2 and CCl3) with cyclohexene afforded mixtures of cis/trans isomer pairs of 1-X-2-Br-cyclohexanes. In addition to benzyl benzoyloxy derivatives are formed also, when benzoyl peroxide is used as an initiator. Owing to the great difficulties in separating these cis/trans isomer pairs, they are identified directly in their mixtures by NMR spectroscopy. In addition to one-dimensional (ID) 1H, proton decoupled 13C and DEPT-135, also two-dimensional (2D) 13C-13C INADEQUATE as well as 1H-13C HMQC experiments have been used in assigning the signals of each compound in their mixtures. The identification of each …
Metabolite identification in human liver needle biopsies by high-resolution magic angle spinning1H NMR spectroscopy
2006
High-resolution magic angle spinning (HR-MAS) 1 H NMR spectroscopy of intact human liver needle biopsies has not been previously reported. HR-MAS NMR spectra collected on 17 specimens with tissue amounts between � 0.5 and 12 mg showed very good spectral resolution and signal-to-noise ratios. One-dimensional 1 H spectra revealed many intense signals corresponding to cellular metabolites. In addition, some high molecular weight metabolites, such as glycogen and mobile fatty acids, could be observed in some spectra. Resonance assignments for 22 metabolites were obtained by combining the analysis of three different types of 1D 1 H spectral editing, such as T2 filtering or the nuclear Overhauser…
MRS SHOWS ABNORMALITIES BEFORE SYMPTOMS IN FAMILIAL ALZHEIMER DISEASE
2006
Background: Pathologic change in Alzheimer disease (AD) begins some years before symptoms. MRS has the potential to detect metabolic abnormalities reflecting this early pathologic change. Presenilin 1 (PS1) and amyloid precursor protein (APP) mutation carriers have a nearly 100% risk of developing AD and may be studied prior to symptom onset. Methods: Short echo time proton MR spectra were acquired from a midline posterior cingulate voxel in presymptomatic carriers of PS1 or APP mutations (“presymptomatic mutation carriers” [PMCs]; n = 7) and age- and sex-matched control subjects (n = 6). Ratios of N-acetyl aspartate (NAA), myo-inositol (MI), and choline-containing compounds (Cho) to creati…
Differential Effects of Dry Eye Disorders on Metabolomic Profile by 1H Nuclear Magnetic Resonance Spectroscopy
2014
We used1H NMR spectroscopy to analyze the metabolomic profile of reflex tears from patients with dry eye disorders (DEDs). 90 subjects were divided into 2 groups: (1) patients with DEDs (DEDG;n = 55) and (2) healthy subjects (CG;n = 35). Additionally, the DEDG was subdivided into 2 subgroups based on DED severity: mild-to-moderate and moderate (n = 22andn = 33, resp.). Personal interviews and systematized ophthalmologic examinations were carried out. Reflex tears (20–30 μL) were collected by gently rubbing in the inferior meniscus of both eyelids with a microglass pipette and stored at −80°C until analysis. NMR spectra were acquired using a standard one-dimensional pulse sequence with water…
Histaminanaloge, 27. Mitt. Bis (2,2′-histamine)
1985
Es wurden p-Phenylen-bis(2,2′-histamin) (6a), Ethylen-bis(2,2′-histamin) (6b), Tetramethylen-bis(2,2′-histamin) (6c) und Hexamethylen-bis(2,2′-histamin) (6d) dargestellt und auf Histamin-H1-und H2-agonistische Aktivitat untersucht. Histamine Analogues, XXVII: Bis(2,2′-histamines) p-Phenylenebis(2,2′-histamine) (6a), ethylenebis(2,2′-histamine) (6b), tetramethylenebis(2,2′-histamine) (6c), and hexamethylenebis(2,2′-histamine) (6d) were prepared and tested for histamine H1,-and H2-agonistic activity.
The first sorbicillinoid alkaloids, the antileukemic sorbicillactones A and B, from a sponge-derived Penicillium chrysogenum strain
2005
The saltwater culture of a Penicillium chrysogenum strain isolated from the Mediterranean sponge Ircinia fasciculata yielded three new sorbicillin-derived compounds (1-3), whose structures were elucidated mainly by 2D NMR and mass spectrometry. Among them, sorbicillactones A (1) and B (2) are the first sorbicillinoid natural products that contain nitrogen. Compound 1 is anti-HIV active and it exhibits a strong cytotoxic activity against L5178y leukemic cells, combined with a relatively low toxicity to cervical carcinoma HeLa S3 cells and pheochromocytoma PC 12 cells. The absolute configurations of I and 2 were elucidated by quantum chemical calculation of circular dichroism (CD) spectra. An…
Pitfalls to be considered on the metabolomic analysis of biological samples by HR-MAS
2014
HR-MAS (High-Resolution Magic AngleSpinning) is considered a powerfultechnique for metabolomic studies ofbiological samples that provides “intact”tissue spectra (Cheng et al., 1998; Waterset al., 2000; Sitter et al., 2002; Martinez-Bisbal et al., 2004; Payne et al., 2006;Coen et al., 2007; Bathen et al., 2010).The performance of HR-MAS, fol-lowed by quantitative histopathology hasdemonstrated that, despite some changes,HR-MAS can preserve approximately thetissue histopathologic features producingwell-resolved spectra of cellular metabo-lites (Cheng et al., 2000). Nevertheless,therearesomeaspectsarousedintheliter-ature about the possible biochemical andstructural changes that can occur durin…
Synthesis, characterization of diorganotin(IV) complexes of N-(2-hydroxyarylidene)aminoacetic acid and antitumour screening in vivo in ehrlich ascite…
2001
Some new diorganotin(IV) complexes have been prepared by reacting potassium N-(2-hydroxyarylidene)aminoacetate with R2SnCl2(R = Me,nBu,Ph). The complexes have been characterized by 1H,13C,119Sn NMR, IR and 119mSn Mössbauer spectroscopic techniques in combination with elemental analysis. In the solid state, the complexes possess penta- and hexa-coordinated tin centres. The hexa-coordinated tin complexes were found to dissociate in solution, giving rise to penta-coordinated species as revealed by 119Sn NMR spectroscopy. Antitumour screening in vivo of the complexes L4snPh2,L4SnPh2· Ph3SnCl and L4SntBU2·t Bu2SnCl2 (L4 = N-(2-hydroxyacetophenone)aminoacetate) is also reported. Copyright © 2001 …
H2-Antihistaminika, 36. Mitt. Isolamtidin und Analoge
1987
Isolamtidin (9a), ein Stellungsisomer des Lamtidins (8a), sowie die analogen N3-substituierten 1-Methyl-1H-1,2,4-triazol-3,5-diamine 9e-i, k wurden durch spezifische Synthese dargestellt und am isolierten Meerschweinchenvorhof und an der histaminstimulierten Sauresekretion der narkotisierten Ratte auf H2-antagonistische Wirkung untersucht. H2-Antihistaminics, XXXVI: Isolamitidine and Analogues Isolamitidine (9a), a position isomer of lamtidine (8a), as well as the analogous N3-substituted 1-methyl-1H-1,2,4-triazole-3,5-diamines 9e-i, k were prepared and tested for H2-antagonistic activity on the isolated guinea-pig atrium and towards the histamine-stimulated acid secretion of the anaestheti…