摘要:

A new method, involving the application of PMR spectrometry for the assay of chlorpropamide and its tablets, is proposed. The PMR spectrum of chlorpropamide has a well-defined triplet (around 0.8 ppm) and quartet (near 7.8 ppm), which are chosen for quantitative analysis. The method is based on comapring the integral of these signals to that of the sharp singlet of maleic acid at 6.3 ppm which is used as internal standard. The proposed method is simple and rapid, also it gives accurate and reproducible results when applied for the analysis of both authentic chlorproparaide and its tablets. In addition, the PMR spectrum obtained helps in confirming identity and purity of the drug.

ISSN:0038-7010    

DOI:10.1080/00387018708081530

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The relative configuration and solute conformation of desacylguayulin A was established using modern NMR techniques. Application of COSY, NOESY, CONOESY, homo- and heteronuclear J-resolved, DEPT and NOEDIFF allowed assignments of all1H and13C NMR resonances.

ISSN:0038-7010    

DOI:10.1080/00387018708081531

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A number of recent investigations have demonstrated the potential of the ultraviolet photoelectron spectroscopy by studies of gazeous equilibrium mixture at low pressure. In particular, the method has been found applicable for studies of tautomerism3,4and prototropy5,6of heterocyclic compounds.

ISSN:0038-7010    

DOI:10.1080/00387018708081532

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The excited level self-alignment is a logical extension of the classical properties1,2of the hollow cathode discharge(HCD).As a result of the magnetic distruction of the aligned levels a Hanle signal with amplitude, width and shape depending upon the plasma parameters, experimental geometry and, finally upon the upper level relaxation constants can be measured.

ISSN:0038-7010    

DOI:10.1080/00387018708081533

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The1H and13C NMR resonances of title compounds were assigned by using 2D and decoupling techniques. The stereochemistry of ring fusion was identified by using, in particular, NOE and COSY1H1H experiments. The low temperature COSY enables the evaluation of the relative populations (2:1) of N-acyl forms of isomeric octahydroindoles resolvable at −60°C.

ISSN:0038-7010    

DOI:10.1080/00387018708081534

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

15N NMR Spectroscopy is one of the most powerful tools to study the structure of organic molecules.1–3δ2-pyrazolines 1 are heterocyclic hydrazones, which as a result of their cyclic structure, are stable in acidic media. Thus, their protonation has been studied by1H and13C NMR spectroscopies.4,5Pyrazolines are protonated and quaternarized at N12 and 3. It is possible to obtain the isomeric quaternary salts 4 by C-protonation of δ3-pyrazolines.6

ISSN:0038-7010    

DOI:10.1080/00387018708081535

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

1H-NMR spectrum of tiaprofenic acid in CDCI3 was obtained and proton chemical shifts from tetramethylsilane were assigned to each proton and set of equivalent protons of the molecule. The hydroxy proton of the carboxylic acid group was confirmed by deuterium exchange. The natural abundance C-13 nuclear magnetic resonance spectrum of the compound in CDCI3 was recorded using Fourier transorm technique. The chemical shifts of carbon resonances have been assigned on the basis of the chemical shift additivity theory and the signal multiplicity observed in the single frequency off-resonance decoupled (SFORD) spectrum. Also comparison with carbon chemical shifts of model compounds were useful.

ISSN:0038-7010    

DOI:10.1080/00387018708081536

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The conformation of the macrocyclic polyoxo-oligo ethers and esters of cation binding ability have been known to play important role due to appropriate orientation of molecular orbitals cousing selective binding on the cationic radii. The oxygen dipoles are enabled to arrange their p orbitals to the direction of delocalised positive charge. The energy transfer -or exchange- between the ion and ligand shell determined the maximum stability and the stoichiometry of the complexation. Accordingly flexibility or the rigidity of the polyoxo-ether-ester ring cousing from the hindered rotation of cyclic lactone mostly determined the degree of association with the cation.

ISSN:0038-7010    

DOI:10.1080/00387018708081537

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Mannich bases are compounds formed from phenols and amines, characterized by intramolecular hydrogen bonds whose strength depends on the substituent implanted on the phenol ring; moreover, as shown by uv measurements, the strength of the interaction for a given phenol derivative depends strongly on the solvent In this work, we have studied the ir spectra of 2,3,4,5-tetrachloro-6-[(diethylamino)methyl]phenol (TCMBH)

ISSN:0038-7010    

DOI:10.1080/00387018708081538

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0038-7010    

DOI:10.1080/00387018708081539

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor