摘要:

1-(4-Aminophenyl)-3-n-propyl-3-azabicyclo[3.1.0]hexane-2, 4-dione, compound1(CGP29953), is an analog of the aromatase inhibitor aminoglutethimide (AG); AG has applications in cancer treatment. We have studied the1H NMR spectra of racemic compound1(in CDC13, ambient temperatures, 300-MHz) with the added achiral LSR, tris(6, 6, 7, 7, 8, 8, 8-heptafluoro-2, 2-dimethyl-3, 5-octanedionato) europium (III), compound2, and the chiral LSR, tris[3-(heptafluoropropylhydroxymethylene)-(+) - camphorato]europium (III), compound3. Use of compound3produced substantial enantiomeric shift differences for several nuclei of compound1.1H-1H COSY spectra were used to determine the relative sense of magnetic nonequivalence for selected nuclei of compound1with added compound3. Relative lanthanide induced shift (LIS) magnitudes for compound1. with added LSR are discussed.

ISSN:0038-7010    

DOI:10.1080/00387019808001643

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Heparin has a high anionic charge density and is known to interact with a large number of cationic dye through electrostatic interaction. To gain insight into the mechanism of interaction of the dye and heparin, we studied the cationic dye-azure A by a spectrophotometric method. The research was based on the fact that the absorption spectra of the free and bound dye are different. It is considered that the combination of heparin with azure A is due to the noncovalent binding forces. The Scatchard model is discussed from a new standpoint. The solution equilibrium of the reaction system was studied. A new linear regression equation has been developed. From this the binding ability of azure A on heparin can be estimated from the equilibrium constant K, and the maximum binding number N. The linear regression equation can determine these two parameters. The factors which influence the sensitivity of a dye binding heparin assay are discussed, and the Sandell index is used to express the sensitivity of heparin detection. It is found that the concentration of the azure A, sodium chloride solutions have significant effect on the interaction of heparin and azure A.

ISSN:0038-7010    

DOI:10.1080/00387019808001644

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

To gain understanding of hindered rotations and magnetic anisotropy in drugs, compounds of much intrinsic importance, we have investigated as amodel compoundthe Diels-Alder adduct of phenycyclone with N-2, 2, 2-trifluoroethylmaleimide for study by1H,19F and13C NMR. The N-2, 2, 2-trifluoroethylmaleamic acid and maleimide precursors were examined by1H and19F NMR. The phencyclone adduct is shown by1H and13C NMR (at 300 and 75 MHz, respectively) to exhibit slow exchange limit spectra at ambient temperatures, arising from hindered rotation of the bridgehead unsubstituted phenyl groups.

ISSN:0038-7010    

DOI:10.1080/00387019808001645

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The Diels-Alder adduct of phencyclone, compound1, withp-fluoranil, compound3, has been prepared in refluxing toluene. The adduct, compound2, has been examined by1H,13C and19F NMR spectroscopy at 300, 75 and 282 MHz, respectively. At ambient temperature, the unsubstituted bridgehead phenyl groups in adduct2are found to exhibit hindered rotation, resulting in slow exchange limit (SEL)1H NMR spectra. Full aryl proton assignments are made based on 1D and 2D (COSY45) NMR. The19F NMR (proton coupled) reveals one of the two19F signals to be a triplet. This resonance collapses to a singlet in the proton decoupled19F spectrum, implying an unexpected long range1H-19F coupling. For the13C NMR spectrum, tentative assignments are presented. Data for compound2as amodel compound for drugsare discussed in terms of the hindered aryl rotation and evidence of magnetic anisotrppic effects.

ISSN:0038-7010    

DOI:10.1080/00387019808001646

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The electron impact mass spectra of some p-substituted styryl-2-benzothiazoles1-6and p-substituted phenyl-butadienyl-2-benzothiazoles7and8have been recorded and the identity of various ions in the mass spectra established.

ISSN:0038-7010    

DOI:10.1080/00387019808001647

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A new spectrophotometric method is introduced for the assay of ternary mixtures with overlapping spectra. The method is based on the use of the first derivative of the ratio spectra and measurements of zero-crossing wavelengths. The ratio spectra were obtained by dividing the absorption spectrum of the mixture by that of one of the components. The concentration of the other components are then determined from their respective calibration graphs treated similarly. The method has been applied for the resolution of two ternary mixtures, namely, dipyridamole, aspirin and salicylic acid (I) and dipyridamole, oxazepam and 2-amino-5-chlorobenzophenone (II). Salicylic acid and benzo-phenone derivative are the degradation products of aspirin and oxazepam, respectively. The proposed method was applied for the assay of these combinations in synthetic mixtures and in commercial dosage forms. The results obtained were precise and accurate.

ISSN:0038-7010    

DOI:10.1080/00387019808001648

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Two different techniques, that is, second (D2) and third (D3) derivative spectrophotometry and fourier transform infrared (FTIR) Spectrophotometry, are investigated for the selective determination of the intact cimetidine in presence of up to 25% and 75% of its degradates, respectively. The procedures determine 2–10 jag ml−1at 224 nm and 217.5 nm by D2and D3, respectively, and 1–6 mg per 250 mg in K Br by the FTIR with mean accuracies of 100.0 ± 1.07%, 100.5 ± 0.87% and 100.3 ± 1.16%, respectively. The drug is successfully analysed in its pharmaceutical formulations.

ISSN:0038-7010    

DOI:10.1080/00387019808001649

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Pottery sherds from the archaeological site of Bancun (Henan, China) were analyzed by Raman microscopy and the pigments used in the coating of this ancient (c.4000–5000 BC) pottery were determined. It was found that bauxite was used to make the white pigment. The black coating was identified as a magnetite and its particle size was in the nanometer range. This work also showed that the size of pigment had influence on the color of the coating. In principle, Raman spectra could be used not only to identify the mineral source of the pigment but also to estimate the particle size of the pigments.

ISSN:0038-7010    

DOI:10.1080/00387019808001650

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Electrospray mass spectrometry (ESMS) of an europium(III) cryptate derived from tris(2-aminoethyl) amine (tren) and 2,6-diformyl-4-chloro-phenol (dcp) is described. The effect of mobile phase, needle voltage and temperature of heated capillary on the ESI process are studied to get the best experimental parameters. The ES-induced fragmentation mechanism is discussed.

ISSN:0038-7010    

DOI:10.1080/00387019808001651

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The most serious problem in multivariate calibration analysis is that the prediction samples may contain the interferents which are not modeled in the calibration step. Then how to detect the interferents and eliminate their influence is significantly important in order to obtain the correct compositional analysis results. The so-called residual spectra library search is supplied and an iterative loop regression algorithm to successfully correct the spectrum containing two interferents is developed in this paper. Three groups of which each sample contains no, one or two interferents are supplied to amplify the above method. The mean relative standard deviation (RSD) for the three groups are 0.163, 0.375, 0.355%, respectively. There are no comparable difference among these RSDs, which proves the validation of the method provided in this paper. The results specify that PLS with FTIR spectroscopy is a powerful tool to resolve both the multicomponent simultaneous determination and the identification of interferents when combined with additional diagnostic and corrected procedure.

ISSN:0038-7010    

DOI:10.1080/00387019808001652

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor