摘要:

Furan and sylvan condense with aldehydes, chlorinated aldehydes and ketones, and keto acids, in the presence of hydrochloric acid. In most cases, the corresponding difurylalkane or difuryl-substituted acid is formed. In special cases the reaction stops at the furylcarbiriol stage.

ISSN:0008-4042    

DOI:10.1139/v56-150

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

In a given experiment, second order kinetics were displayed during the greater part of the reaction over a considerable range of initial concentrations of reactants. In general, the second order behavior was maintained to greater extent of reaction when hydrazobenzene was in excess. The calculated second order rate constant,k, decreased with increase in initial hydrazobenzene concentration and increased with increase in initial concentration of ammonium persulphate. For different equimolar concentrations of reactants,kwas virtually independent of initial concentrations. The value ofkwas proportional to the square root of the ratio of the initial concentrations of persulphate and hydrazobenzene. The activation energy of the over-all reaction was 16 kcal. per mole. A free radical mechanism appears to account reasonably well for the major experimental observations.

ISSN:0008-4042    

DOI:10.1139/v56-151

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Candidin, the antifungal antibiotic produced byStreptomycesviridoflavus, has been isolated in crystalline form. Analyses and equivalent weight values best fit a molecular formula C46H75NO17. The substance is amphoteric and probably contains one carboxyl and one amino group. Infrared spectral evidence also indicates a polyhydroxylated structure, and the absorption in the visible region shows the presence of a conjugated heptaene chromophore. An additional conjugated diene elsewhere in the molecule is suggested by hydrogenation values and the absorption maximum at 228 mμ.

ISSN:0008-4042    

DOI:10.1139/v56-152

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

From highly polymerized deoxyribonucleate the nucleosides have been isolated by an improved method. The sugar obtained on hydrolysis of the individual nucleosides has been shown to beD-2-deoxyribose in each case.

ISSN:0008-4042    

DOI:10.1139/v56-153

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The distribution of plutonium between neutron-irradiated uranium and some rare earth metals has been examined as a function of temperature in the range 1160° to 1350 °C. The results are used to calculatethe limiting partial molal heat content of plutonium, at 1250 °C. in lanthanum, cerium, neodymium, and a commercial preparation of mixed rare earths (misch metal). The following values (in kilocalories) were obtained: lanthanum 2.9, cerium 1.1, neodymium 0.0, and misch metal 1.1. The maximum error associated with these values is ±0.4 kilocalories.

ISSN:0008-4042    

DOI:10.1139/v56-154

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

A synthesis of the hitherto unreportedL-serylglycylglycine by two different methods is described. N-carbobenzoxyL-serylglycylglycine benzyl ester, an intermediate in the preparation of the tripeptide, was found to be a suitable derivative in the synthesis ofL-α-phosphatidylL-serylglycylglycine.

ISSN:0008-4042    

DOI:10.1139/v56-155

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Four minor alkaloids ofL.annotinumhave been examined by chemical methods and infrared spectroscopy for their functional groups. Acrifoline (L.27) C16H23O2N has a double bond, a carbonyl group, and an hydroxyl function. Annotine (L.11) C16H21O3N has a double bond, a carbonyl group, an hydroxyl function, and an inert oxygen probably present in an ether linkage. Alkaloid L.12 (C18H25O3N) isO-acetylacrifoline. Alkaloid L.8 (C16H25O2N) has only been studied by infrared spectroscopy where it shows carbonyl and hydroxyl absorption. All four alkaloids therefore contain a basic tetracyclic ring system as do the majority of other lycopodium alkaloids. Annotoxine, a molecular compound of acrifoline and annotine, has been isolated from extracts of Canadian plant material.

ISSN:0008-4042    

DOI:10.1139/v56-156

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Evidence is presented which supports an earlier suggestion that the linkage-position in a reducing disaccharide may be determined readily by lead tetraacetate oxidation. Compounds examined include aldose and ketose disaccharides and aldobiuronic acids. Two types of reaction—one catalyzed by potassium acetate and the other non-catalyzed—are employed jointly to illustrate oxidation patterns which clearly differentiate each position of the biose linkage. Partial degradation of reducing disaccharides by lead tetraacetate oxidation is illustrated by the preparation of 2-O-α- and 2-O-β-D-glucopyranosyl-D-erythritol and 4-O-β-D-galactopyranosyl-D-erythritol. In turn, 2-O-β-D-glucopyranosyl-D-erythritol is degraded to 2-O-β-D-glucopyranosyl-glycerol.

ISSN:0008-4042    

DOI:10.1139/v56-157

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The density data for aqueous solutions of electrolytes have been analyzed, and partial molal volumes at infinite dilution have been calculated. The values are shown to be additive, and a set of volumes for individual ions has been prepared, based arbitrarily on a value of zero for the hydrogen ion. It is shown that for a given value of the charge the volumes vary linearly with the cube of the ionic crystal radii, and for a given radius vary with the first power of the charge. In the case of cations the equation obeyed iswhile for anionsIf the volume of the hydrogen ion is taken as −6 ml. instead of zero the same equation is obeyed for both cations and anions, namelyThe empirical equations are discussed in terms of a simple model for ions in solution.

ISSN:0008-4042    

DOI:10.1139/v56-158

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Critical examination of the available experimental information provides rather convincing evidence that atomic nitrogen is the main reactive species in active nitrogen. It appears quite unlikely that a significant contribution to the activity is made by electronically excited molecules, metastable atoms, ions, or triatomic radicals. Evidence exists, however, for the presence of more than one active species, and a plausible suggestion would seem to be that the second species is vibrationally excited molecules. Consideration of the role of spin conservation in reactions of active nitrogen leads to the conclusion that reactions that conserve spin occur more readily than those in which spin is not conserved.

ISSN:0008-4042    

DOI:10.1139/v56-159

出版商:NRC Research Press    

年代:1956

数据来源: NRC