摘要:

Thin layer chromatography on silica gel G with benzene–methanol mixtures is a rapid method for the analytical or semimicro preparative separation of low molecular weight carbohydrate acetates. Some mixtures of inositol acetates are also resolved by the same procedure. A sensitive spray reagent has been developed for the analytical detection of acetates on the chromatographic plates and is based on the formation of the ferric hydroxamate of acetic acid. Oligosaccharide acetates are easily detected on a semimicro preparative scale by spraying the chromatographic plates with water, a general, non-destructive method for detection of hydrophobic compounds. The chromatograms can be run in 40 minutes and multiple development can be carried out to improve resolution when necessary.

ISSN:0008-4042    

DOI:10.1139/v62-159

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

2,3,4,6-Tetra-O-acetyl-D-glucosyl-(N-bis-β-chloroethyl)-phosphoramidate and ethyl-D-fructopyranoside-1-(N-bis-β-chloroethyl)-phosphoramidate have been synthesized. The first compound inhibited Adenocarcinoma 755 to 40–50%.

ISSN:0008-4042    

DOI:10.1139/v62-160

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Reactions of some diketones with thiosemicarbazide have been studied under various conditions. Monothiosemicarbazones, dithiosemicarbazones, and cyclization products can be obtained. It was found that dithiosemicarbazones form 1:1 complexes with Cu(II) but failed to react with Cu(I). Dithiosemicarbazones in which the N2-hydrogen atom has been replaced by Me do not form complexes, confirming our views about the importance of this hydrogen atom in the thione ↔ thiol tautomerism necessary for complex formation. 4,4-Dimethyldithiosemicarbazones behave like the unsubstituted parent compounds in forming 1:1 complexes with Cu(II). Infrared spectra provide evidence for the structure of a cyclization product, 5,6-diphenyl-3-thio-1,2,4-triazine, which had been erroneously described by various authors as the thiol tautomer, 5,6-diphenyl-3-mercapto-1,2,4-triazine.

ISSN:0008-4042    

DOI:10.1139/v62-161

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The electron spin resonance of an X-ray-irradiated single crystal ofdl-alanine hydrochloride indicates that the radical formed is probably the same as that produced by X- and γ-ray irradiation of alanine. The components of the hyperfine interaction tensor for the radical have been evaluated.

ISSN:0008-4042    

DOI:10.1139/v62-162

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The ionization of nitrogen dioxide by photons has been studied using a photoionization mass spectrometric technique and also by the ordinary electron impact method. The photoionization results show a large variation in the relative ionization efficiency within the energy range 9–14 ev, and help to explain the differences between previously reported values for the first ionization potential of this compound. The photoionization efficiency curve indicates the first ionization potential to lie at 9.8 ev and inner ionization potentials to lie at about 11.1 and 12.7 ev.The electron impact ionization efficiency curve for the NO2+ion exhibits a low ion intensity near the threshold. This confirms the viewpoint that previous determinations of the first ionization potential have employed threshold energy measuring techniques not properly suited for the type of molecule such as nitrogen dioxide which radically changes symmetry on ionization.

ISSN:0008-4042    

DOI:10.1139/v62-163

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Evidence is furnished which establishes the structure of a new alkaloid isolated fromLycopodiumflabelliforme.

ISSN:0008-4042    

DOI:10.1139/v62-164

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Chemical shift data for the formyl proton in some 30 aromatic aldehydes are reported. It was found that meta- and para-substituted benzaldehydes exhibited this peak in the range 9.65–10.20 δ, while ortho-substituted compounds appear at lower field, 10.20–10.50 δ; the former shifts show an approximate correlation with the Hammett sigma parameter. Evidence for steric inhibition of resonance is presented for some ortho-substituted compounds and some interesting solvent effects are discussed.

ISSN:0008-4042    

DOI:10.1139/v62-165

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

A study has been made of the discrepancy between the N-atom content of active nitrogen as inferred from the maximum HCN production from the reaction of many hydrocarbons, and that indicated by the extent of NO destruction. The HCN production from several hydrocarbons was similar at high reaction temperatures in a spherical reaction vessel, and was independent of reaction temperature in a cylindrical reaction vessel. The ratio (NO destroyed)/(HCN produced) was found to be independent of the mode of excitation òf the molecular nitrogen and of the N-atom concentration, and to be unaffected by the addition, upstream, of N2O or CO2. Although NH3was found to be a minor product of the hydrocarbon reactions, HCN accounted for at least 96% of the N-atom content of the products under conditions where its formation is considered a measure of the N-atom concentration. The NO "titration" value, the maximum extent of HCN production from C2H4, and the destruction of NH3after different times of decay of active nitrogen gave evidence that part of the NO reaction occurred, as does the NH3reaction, with excited nitrogen molecules. The long lifetime of the N2* species capable of reaction with NO or NH3, as calculated from the above data, strongly favors its identification as low vibrational levels of the N2(A3∑u+) molecule. A consideration of the values for the NO/HCN, NH3/HCN, and NH3/NO ratios, after different times of decay, for poisoned and unpoisoned systems, suggested that the N2* responsible for the NH3reaction is formed only during homogeneous recombination of N atoms, while the N2* responsible for reaction with NO might be produced by wall recombination as well. Possible reactions of excited molecules present in the active nitrogen – NO system that might lead to decomposition of NO without consumption of N atoms are discussed.

ISSN:0008-4042    

DOI:10.1139/v62-166

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The preparation of an octapeptide, carbobenzoxy-(β-benzylester)-L-aspartyl-nitro-L-arginyl-L-valyl-L-tyrosyl-L-isoleucyl-(im)benzyl-L-histidyl-L-prolyl-L-phenylalanine methyl ester, a derivative of angiotensin II, is described.

ISSN:0008-4042    

DOI:10.1139/v62-167

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Interaction of solid silver fluoborate with the gaseous olefins ethylene, propylene, and the four butenes has been observed to provide 12 new stoichiometric solid coordination compounds (silver fluoborate – olefin complexes) of high stability. Experimental investigation of the univariant pressure–temperature stability lines for the complexes has been made and the thermodynamic functions calculated: the heat content change for complex dissociation is between 9 and 13 kcal/mole of olefin liberated. Infrared spectra of the complexed olefins indicate that the strength of the silver–olefin bond is primarily dependent upon the basicity of the olefin and a comparison of the thermodynamics of dissociation shows anomalous behavior on the part of isobutylene andtrans-2-butene as compared with the regularity displayed by the other four olefins.

ISSN:0008-4042    

DOI:10.1139/v62-168

出版商:NRC Research Press    

年代:1962

数据来源: NRC