Proton magnetization magnetic resonance spectroscopy

In favorable cases, cyclization reactions may be useful in estab-hshing configurations, but these methods may also be complicated by isomerizations. It is clear that other approaches are necessary to resolve this structural question. This has been accomplished recently for the isomers of a related system (55) using proton magnetic resonance spectroscopy. 

The rate of formation of the pseudooxazolone may be followed conveniently by proton magnetic resonance spectroscopy. ... 

Studies of Deoxy Sugars by Proton Magnetic Resonance Spectroscopy... 

The reaction can be followed by proton magnetic resonance spectroscopy. The original absorption for the vinyl proton disappears and two new absorption peaks appear, one in the vinyl region (ca. <5 6.5, chloroform-d) and the other in the methine region of the spectrum. There are two products formed, presumably the cis- and tfraws-isomers, in the ratio of 95 5, respectively. The checkers also obtained the same yield when the reaction quantities were doubled. 

The progress of the reaction is followed by proton magnetic resonance spectroscopy. When the absorption for the vinyl proton (ca. <5 6.6, chloroform-d) is completely absent, the reaction is stopped. Several minor products that were not identified are also formed in this step. 

Yields higher than about 70% for any of these isonitrile preparations generally indicate incomplete fractionation. The purity of the product may be conveniently checked by proton magnetic resonance spectroscopy. The characteristic 1 1 1 triplet for tert-butyl isocyanide appears at <5 1.45 (chloroform-d). A small upheld peak usually indicates the presence of unreacted amine. Other common contaminants are dichloromethane and chloroform The purity may be determined more accurately by gas chromatographic analysis on a 230 cm. by 0.6 cm. column packed with 10%SE30 on Chromosorb G, 60-80 mesh, at 80°. 

Ethyl chloroformate obtained from Aldrich Chemical Company, Inc., was distilled, b.p. 93°. The progress of the reaction may be followed by proton magnetic resonance spectroscopy. Aliquots are partitioned between dichloromethane and water, the organic layer is concentrated, and the spectrum is recorded. A quartet from the ethoxy group of the mixed anhydride appears at 8 4.2. Ethyl chloroformate, which exhibits a quartet at 6 4.3, is removed in the concentration step. 

The identity and purity of the product were determined by gas chromatography, infrared spectroscopy, and proton magnetic resonance spectroscopy by both the submitters and the checkers. 

Yield determined by proton magnetic resonance spectroscopy. 

Proton magnetic resonance spectroscopy. 2. Nuclear magnetic resonance spectroscopy. I. Hollerton, J. C. (John C.), 1959- II. Title. 

Christensen, J. D., Kaufman, M. J., Frederick, B. et al. Proton magnetic resonance spectroscopy of human basal ganglia response to cocaine administration. Biol. Psychiat. 48 685-692, 2000. 

Negendank, W. G., Sauter, R., Brown, T. R. et al. Proton magnetic resonance spectroscopy in patients with glial tumors a multicenter study. /. Neurosurg. 84 449-458, 1996. 

Herminghaus, S., Frolich, L., Gorriz, C. et al. Brain metabolism in Alzheimer disease and vascular dementia assessed by in vivo proton magnetic resonance spectroscopy. Psychiat. Res. 123 183-190, 2003. 

Simister, R. J., McLean, M. A., Barker, G. J., Duncan, J. S. A proton magnetic resonance spectroscopy study of metabolites in the occipital lobes in epilepsy. Epilepsia 44 550-558, 2003. 

Proton magnetic resonance spectroscopy has been used in many cases 6>7> 17,33,40,47) order to characterize iminoboranes. These spectra are of particular value for distinguishing between possible stereoisomers 6.17.47), On the basis of 19F n.m.r. it has been established that the compound [CF3CX=N—BX2]2 (X = Q, Br) exists as mixtures of isomers, since the resonance signal appeared as a doublet 4>. 

Bailey, K., and Grey, A. A. (1972) A conformational study of lysergic acid and iso-lysergic acid dialkylamides by proton magnetic resonance spectroscopy. Can. J. Chem., 50 3876-3885. 

Ronayne, J., Williams, D. H. Solvent Effects in Proton Magnetic Resonance Spectroscopy. Annual Review of NMR Spectroscopy, Vol. 2,pp. 83-124, New York 1969. Laszlo, P. Solvent Effects and Nuclear Magnetic Resonance. Progr. N.M.R. Spectroscopy 3, 231-403(1968). 

Information concerning the tertiary structure of the proteins has been obtained from fluorometry, proton magnetic resonance spectroscopy, limited proteolysis, and X-ray analysis of protein crystals. 

GaUinat J, Lang UE, Jacobsen LK, Bajbouj M, Kalus P, von Haebler D, et al (2007) Abnormal hippocampal neurochemistry in smokers evidence from proton magnetic resonance spectroscopy at 3 T. J CUn Psychopharmacol 27(l) 80-84... 

Recently, a uranium complex with p3Trol anion has been prepared and characterized by proton magnetic resonance spectroscopy 90). 

Hamakawa, H., Kato, T, Shioiri, T, Inubushi, T., and Kato, N. (1999) Quantitative proton magnetic resonance spectroscopy of the bilateral frontal lobes in patients with bipolar disorder. Psychol Med 29 639-644. 

Sanacora, G., Mason, G.F., Rothman, D.L., Behar, K.L., Hyder, E, Petroff, O.A., Berman, R.M., Charney, D.S., and Krystal, J.H. (1999) Reduced cortical gamma-aminobutyric acid levels in depressed patients determined by proton magnetic resonance spectroscopy. Arch Gen Psychiatry 56 1043-1047. 

B. (1999) Metabolic changes in the brain of patients with anorexia and bulimia nervosa as detected by proton magnetic resonance spectroscopy. Int Eat Disord 26 119-136. 

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