ISSN:0165-0513    

DOI:10.1002/recl.19530720302

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY

摘要:

Abstract4‐Methylsulphonyl‐3,5‐xylenol has been prepared by a series of reactions involving thiocyanation, reduction with LiAlH4, methylation, and oxidation. The methylsulphonyl group exerts a negative mesomeric effect, which, however, is not hindered by ortho methyl groups. The spectrum as well as the ionization constant prove this. For the latter property, additivity of Hammett's σ‐constants for groups in the 3, 4, and 5 positions was taken as a criterion. For sulphur, as a second‐row element, coplanarity of its SO‐valencies and the benzene nucleus is no condition for maximum resonance. Throughout this paper, the data of the corresponding nitro compounds have been measured fo

ISSN:0165-0513    

DOI:10.1002/recl.19530720303

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY

摘要:

AbstractAccording toRodionowandFedorowa1), Hofmann degradation of 4‐hydroxy‐phthalimide yields 2‐amino‐4‐hydroxy‐benzoic acid. This has been shown to be incorrect. Only 2‐amino‐5‐hydroxy‐benzoic acid could be isolated from the reaction mixture. The spectra of both the acids mentioned were measured, and a few deriva

ISSN:0165-0513    

DOI:10.1002/recl.19530720304

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY

摘要:

AbstractThe hydrolysis of methylene diurea giving urea and monomethylolurea was found to be a monomolecular reaction. The rate of the reaction is directly proportional to the hydrogen ion concentration in the pH range measured (3‐5) and independent of the buffer concentration. The activation energy appeared to be 19.5 kcal.Generally, the reaction of an amidomethylol group with an amide group leading to the formation of a methylene bridge between urea fragments, will be a reversible reaction. The rates of both the forward and the reverse reactions are proportional to the hydrogen ion concentratio

ISSN:0165-0513    

DOI:10.1002/recl.19530720305

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY

摘要:

AbstractThe reaction between monomethylolurea and methylene diurea appeared to be bimolecular and the rate constants were found to be directly proportional to the concentration of the hydrogen ions. An influence of the buffer concentration was not observed. The activation energy was found to be 15 kcal/mol.

ISSN:0165-0513    

DOI:10.1002/recl.19530720306

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY

摘要:

AbstractThe reaction of methylene diurea with formaldehyde showed a close resemblance to the previously studied reaction of urea and formaldehyde1), i.e. the reaction appeared to be bimolecular and the rates were found to be directly proportional to the concentration of hydroxyl ions while further an influence of the buffer concentration on the rates was observed. Obviously the reaction is subject to a general acid and/or base catalysis. The activation energy appeared to be about 15 kcal/mol. The values for the rate constants were almost the same as were found for the reaction between urea and formaldehyde.

ISSN:0165-0513    

DOI:10.1002/recl.19530720307

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY

摘要:

AbstractL'influence des concentrations des bains acides, sur le processus de régénération de la cellulose à partir de la viscose a été éxaminée. La méthode statique employée, en dehors de la filature, est basée sur la mesure de L'épaisseur de la couronne de cellulose, apparaissant lorsqu'on trempe un cylindre de viscose dans ces bains. On propose une interprétation

ISSN:0165-0513    

DOI:10.1002/recl.19530720308

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY

摘要:

AbstractL'hétérogénéité de la vagotonine a été signalée par quelques auteurs. Nous avons étudié le comportement de cette substance et des différentes fractions isolées par précipitation saline, à L'électrophorèse et à L'ult

ISSN:0165-0513    

DOI:10.1002/recl.19530720309

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY

摘要:

AbstractNos premiers essais de fractionnement de la vagotonine isolée du pancréas parSantenoise1) nous ont amenés à séparer par précipitation fractionnée au sulfate de lithium deux fractions de solubilités différentes2). Nous avons par la suite fractionné de nouveau la portion la plus soluble, et dans une précédente communication3), nous avons décrit leur comportement électrophorétique. Ces substances se sont révélées non homogènes à L'électrophorèse et renferment trois composés principaux accompagnés d'autres protéines en proportions plus faibles. Nous avons voulu vérifier si cette hétérogénéité se manifestait également lors de la sédi

ISSN:0165-0513    

DOI:10.1002/recl.19530720310

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY

摘要:

AbstractThe synthesis of one of the stereoisomeric forms (probably the threo‐form) ofDL‐2‐dichloroacetamido‐1‐(4‐pyridyl)‐1,3‐propanediol, the pyridine analogue of chloramphenicol, is described.Its activity againstSalm. typhimuriumandEbert. typhiis 1‐3 per cent of that of chl

ISSN:0165-0513    

DOI:10.1002/recl.19530720311

出版商:WILEY‐VCH Verlag    

年代:1953

数据来源: WILEY