摘要:

AbstractUltraviolet absorption spectra are recorded ofcis‐andtrans‐cinnamic acid, ofcis‐andtrans‐1,2,3,4,‐tetrahydronaphthylidene (1) acetic acid and ofcis‐andtrans‐β‐(naphthyl‐1) acrylic acid. Thecisisomers all show a lower extinction coefficient and a shift of the maximum of absorption to shorter wave‐length in comparison with thetransisomers. It is concluded that as a result of steric hindrance in the case of theciscompounds the conjugation between aromatic ring system and carboxyl group is hindered, the molecules not possessing a plane structure. The fact that all theseciscompounds show marked activity as plant growth promoter, whilst thetransisomers are totally inactive, is in accordance with the conclusions about their stereochemical structure. Comparison of the ultraviolet absorption spectra of stilboestrol and ofp,p′‐dihydroxystilbene leads to the conclusion that the stilboestrol molecule does not have a plane structure and that it is doubtful whether the explanation of the oestrogenic activity based on its often suggested „formal”︁ similarity to the natural oes

ISSN:0165-0513    

DOI:10.1002/recl.19480671102

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY

摘要:

AbstractIn connection with the hypothesis that plant growth substances do not exert their growth promoting activity by a chemical reaction proper (e.g.functioning as redox‐catalysts) but by a more physical type of action on certain structures in the living cell, experiments were made on the influence of these compounds on monolayers of lecithin or oleic acid spread on aqueous solutions.It was found that apparently plant growth substances penetrate into and accumulate in such monolayers, their influence generally consisting in seemingly increasing the molecular area in the film. In some cases (decahydro‐naphthylacetic acid or undecanoic acid in the hypophases) very peculiar curves were obtained.The activity of a number of compounds tested in this way may be understood by considering the balance between the lipophilic part of the molecules and the hydrophilic carboxyl group.Although the type of action proved to be qualitatively as expected, a parallelism between the growth promoting activity of the compounds and their influence on these simple surface layers does not exist.Further detailed studies must provide an answer to the question whether the difference between the action in the model systems and in vivo might be caused by the apparently much too simple and aspecific composition of the films used, or whether, with the ideas put forward inH. Veldstra, Enzymologia11, 97, 137 (1944)., the physiological action has been simplified too m

ISSN:0165-0513    

DOI:10.1002/recl.19480671103

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY

摘要:

AbstractDiethyldichlorosilane reacts with dry ammonia to give hexaethylcyclotrisilazine. Intermediates in this reaction are linear ethylsilazines which may contain chlorine atoms.The silazines decompose under the influence of moisture into NH3, diethylsilanediol and silicones.The preparation of diethyldichlorosilane from silicon tetrachloride and ethylmagnesium bromide has been improved.

ISSN:0165-0513    

DOI:10.1002/recl.19480671104

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY

摘要:

AbstractGlutaric acid and pimelic acid have analogous crystal structures. The CH2chains are stretched along the c‐axis, the plane of the zigzag is nearly parallel to (100). Packing of the COOH groups is practically identical to that in adipic acid. This packing enforces a torsion in the molecules of the odd acids as a result of their axial symmetry. This torsion may well be the cause of the higher energy content of the odd dicarboxylic acids; an estimate of the torsion energy is made and is shown to be of the right order of magnitud

ISSN:0165-0513    

DOI:10.1002/recl.19480671105

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY

摘要:

AbstractL'isomérisation des sulfones cycliques des butadiènes consiste en un déplacement de la double liaison de la position β à la position α par rapport au groupe sulfonyle. Le fait qu'on n'a pas pu réaliser cette réaction chez une sulfone non saturée acyclique (allylbenzylsulfone) doit être attribué à des conditions qui provoquent une addition du solvant. A l'aide d'amines tertiaires, les auteurs ont réussi cette isomérisation.L'addition d'alcool, de phénol, en présence de leur dérivé sodique, et d'amines donne, dans chaque cas, un seul produit substitue en position β. Ces additions s'accomplissent probablement par l'intermédiaire de la sulfone isomère (propénylbenzylsulfone), qui prend naissance en milieu nucléophile.L'addition de l'acide iodhydrique à l'allylbenzylsulfone donne deux isomères, les iodures β et γ. Lorsqu'on chauffe le mélange avec de l'ammoniac alcoolique, le β‐iodure perd de l'acide iodhydrique en engendrant la propénylbenzylsulfone;

ISSN:0165-0513    

DOI:10.1002/recl.19480671106

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY

摘要:

AbstractLe tétrakis‐méthylthio‐méthane, en présence d'acide perbenzoïque en excès, consomme 7 à 8 atomes d'oxygéne. En lavant le produit d'oxydation à l'eau, on élimine de l'acide méthanesulfonique.Le résidu est un mélange, dont on peut séparer, par des procédés variés, le tris‐méthylsulfonyl‐méthane CH(SO2Me)5(acide fort). Le principal composant du mélange peut engendrer une sulfoxyde‐disulfone (MeSO)CH(SO2Me)2, dont il est peut‐étre un isomère; il se décompose à 110° en donnant l'acide méthanesulfonique, le dioxyde de diméthyldisulfure Me2S2O2et d'autres produits encore. II n'est pas impossible qu'une tétrasulfone se soit formée parmi les produits primaires de l'oxydation, et, si c'est le cas, elle s'est décomposée rapidement.En introduisant deux groupes thiométhyle dans le bis‐méthylsulfonyl‐méthane, on synthétise un dérivé du tétrathioéther avec deux groupes sulfonyle (MeS)2C(SO2Me)2, dérivé qui, soumis à l'oxydation, se comporte, dans les grand lignes,

ISSN:0165-0513    

DOI:10.1002/recl.19480671107

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY

摘要:

AbstractLe potentiel d'écoulement de cristaux de BaSO4en milieu hydroalcoolique a été mesuré. Dans certains cas on observe une positivation des cristaux. Ce phénomène parait étre dû à une désorption des ions sulfuriques ou à l'adsorption des i

ISSN:0165-0513    

DOI:10.1002/recl.19480671108

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY

摘要:

AbstractA new method is described to determine the oil content of waxy oils. The oil content is determined as a function of the pour point of the dewaxed oil. The waxy oil is dissolved in a mixture of butanone and toluene of a suitable composition, after which part of the wax is precipitated by cooling the solution down to certain temperatures and separated by filtration. The oil in the wax cake is removed by repeated stirring with fresh solvent. By successively adding the extracts of the wax cake to the dewaxed oil and repeating the pour point determination, the maximum quantity of oil of a certain pour point is determined.

ISSN:0165-0513    

DOI:10.1002/recl.19480671109

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY

摘要:

AbstractAnthracene used in certain industrial processes must be substantially free from carbazole. No simple method, suitable for the routine determination of the carbazole content of semi‐refined and refined technical anthracenes ‐ containing up to about 6 % and less than 1 % carbazole respectively ‐ appears to be available in the literature. An investigation which ultimately led to the development of a suitable method was accordingly undertaken. The results are summarised in the present

ISSN:0165-0513    

DOI:10.1002/recl.19480671110

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19480671101

出版商:WILEY‐VCH Verlag    

年代:1948

数据来源: WILEY