Methods Of PMR Spectroscopy Research Articles

Synthesis and characterization of N-fluoroalkylsulfonamides

In this paper a convenient method for the preparation of N-fluoroalkylsulfonamides will be discussed. Methods have been developed for the introduction of fluoro-groups into the N-alkyl-sulfonamides by reaction with fluorogenat inorganic oxidizers [F 2/Ar (1–3%), XeF 2]. Under the action of XeF 2 or F 2, N-alkyl-sulfonamides undergo fluorination to form N-fluoroalkylsulfonamides in yields of more than 70%: ▪ R′ = R″ = Ph R″ = CH 3, nCH 3C 6H 4 R‴ = H, Na, K The compounds were identified by IR, NMR-F, and PMR spectroscopy methods and by chemical analysis.

Study of the equilibrium copolymerization of dimethyl- and methyl(3,3,3-trifluoropropyl)cyclosiloxanes

By the methods of PMR spectroscopy and GLC, the changes in the composition and microstructure of the copolymers, as well as the composition and yield of cyclosiloxanes were studied in the course of the equilibrium anionic copolymerization of 1,3,5-trimethyl-1,3,5-tris-(3,3,3-trifluoropropyl)cyclotrisiloxane (F 3) with dimethylcyclosiloxanes. It was shown that even after the equilibrium yield of the copolymer has been reached, its microstructure and composition of rings continue to change. As the polymerization of F 3 in the given medium is considerably more rapid than the homopolymerization, the assumption is presented that the dimethylcyclosiloxanes play a promoting role.

Identification of aminoglycoside antibiotics by the method of PMR spectroscopy

The method of PMR spectroscopy is now in rather wide use in the analysis of drug preparations [i], including the identification of aminoglycoside antibiotics [2]. However, the use of PMR spectroscopy in the latter case is difficult, since the spectra of a number of antibiotics -streptomycin (I) [3, 4], dihydrostreptomycin (II) [3, 5, 6], neomycin B (III) [7], monomycin A (IV; synonym: paromomycin) [8], kanamycin A (V) [8, 9], tobramycin (V!) [i0], gentamycin (VIII) [11, 12], and sisomycin (VIII) [13, 14] --

Quantitative determination of 6- and 2-phenylazo-3,4-xylyl-D-ribitylamines in a mixture by the method of PMR spectroscopy

Quantitative determination of 6- and 2-phenylazo-3,4-xylyl-D-ribitylamines in a mixture by the method of PMR spectroscopy

Determination of the relative content of kanamycin B in kanamycin sulfate preparations by the method of PMR spectroscopy

Determination of the relative content of kanamycin B in kanamycin sulfate preparations by the method of PMR spectroscopy

Structural peculiarities and properties of poly(isopropenyl ethynyl trimethyl piperidole)

A study has been made of the homopolymerization of isopropenyl ethynyl trimethyl piperidole in bulk and in solution under the action of H 2SO 4, using a radical initiator. The polymer structure has been analyzed by IR and PMR spectroscopy methods, and the properties of dilute solutions of the polymer determined. Polymerization takes place by a radical mechanism, and the structure of the macromolecules is represented by a linear containing side piperidle rings that are interconnected by H bonds with participation of water of hydration molecules. The properties of a dilute solution of the iodomethylate of poly(isopropenyl) ethylnyl trimithyl piperidole) have been investigated, and the results interpreted in the light of concepts of the behaviour of polyelectrolytes.

A study of the reactions of alkyl compounds of mercury and group IVb elements with triarylmethane salts by PMR spectroscopy

1. The methods of PMR spectroscopy have been used to study the reactions of dipropylmercury, di-n-butylmercury, tetraethyltin, tetrapropyltin, and diisobutylgermanium with triarylmethane salts. 2. Hydride displacement from the metalorganic compound to the triarylmethyl cation proceeds in phase with the breaking of the carbon-metal and β-carbon-hydrogen bonds.

The reaction of sulfur halides with unsaturated compounds

1. The reaction of SCl2 with cyclohexene results in the formation of d,l-bis(2-chlorocyclohexyl)sulfide and meso-bis(2-chlorocyclohexyl) sulfide. Investigation of the PMR spectra of the deuterated compounds has established that the dichloro sulfides have conformational mobility and are equilibrium mixtures of the diequatorial and diaxial forms. 2. The method of PMR spectroscopy in the presence of the shift reagent Eu(fod)3 and measurement of the dipole moments have been employed to establish the structures of the sulfoxides and sulfones.

Study of the stereochemistry of N-acyliminodibenzyls by the method of PMR spectroscopy

Study of the stereochemistry of N-acyliminodibenzyls by the method of PMR spectroscopy

Enolization of phosphorylated derivatives of formylacetic acid

1. A quantitative evaluation of the position of equilibrium of diethoxyphosphinylformylacetonitrile, diethoxyphosphinylformylethyl acetate, and formylcyanoacetic ester in various solvents was performed by the method of PMR spectroscopy. 2. In not one case was the presence of the aldo-form detected in the tautomeric mixture. For diethoxy-phosphinylformylacetonitrile and formylcyanoacetic ester, a tautomeric equilibrium of the cis- and trans-enol forms is observed; the content of the latter increases with increasing polarity of the solvent. For diethoxy-phosphinylformylethylacetate, two cis-enol forms exist at equilibrium, with predominance of the structure with an intramolecular hydrogen bond with the P=O group.