摘要:

It has been shown by nitration with a mixture of 99–100% nitric acid and acetic anhydride that 2-nitraminothiazoles, such as 2-nitramino-5-nitrothiazole and 4-methyl-2-nitramino-5-nitrothiazole, can react in the tautomeric nitrimino form. The nitration occurs in the three position of the thiazole ring. Compounds with an acetamido group in the two position of the thiazole ring, such as 2-acetamido-5-bromo-2-thiazole and 2-acetamido-5-methylthiazole, can also be nitrated in the three position indicating the tautomeric change from the acetamido to the acetimido group.

ISSN:0008-4042    

DOI:10.1139/v53-118

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

Lycopodiumdensumhas yielded lycopodine and two apparently new alkaloids, L34, C16H25O2N, and L35, C14H21ON The total alkaloid content of the plant was less than 0.1%.

ISSN:0008-4042    

DOI:10.1139/v53-119

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

Absorption spectra of a number of substituted aryl-andsym-diarylureas have been determined in ethanol. As conjugation in the chromophores increased, a gradual displacement of the maxima of the conjugative absorption band towards the visible occurred. This displacement was accompanied by a progressive increase in intensity of absorption. The effect on the absorption spectra of replacing hydrogen of the aryl substituents by alkoxy, methyl, or halogeno groups is discussed. A relationship between the inductive effect of these groups and their influence on the absorption spectra is indicated.

ISSN:0008-4042    

DOI:10.1139/v53-120

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

The mass spectrometer has been used for the estimation of trace quantities of rubidium and strontium. The isotope dilution technique developed by Aldrich has been extended so that 0.01% of rubidium and 0.0001% strontium have been analyzed with 100 mgm. of mineral. The use of small quantities for mass spectrometric determination allows the use of easily available fission strontium and rubidium. The radioactivity of the fission strontium also simplifies the chemical manipulation. No chemical separation from the mineral was required for the rubidium but the strontium was concentrated by ion exchange methods. Ages are presented for one lepidolite and two biotite minerals and their ages compared to those found by other methods. With one of the biotites the effect of weathering on the fractionation of rubidium from strontium has been studied.

ISSN:0008-4042    

DOI:10.1139/v53-121

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

A new mechanism for oxidations by persulphate is presented, wherein it is postulated that the persulphate ion dissociates reversibly, by means of a heterolytic cleavage, into a sulphate ion and a molecule of sulphur tetroxide. Sulphur tetroxide is considered to be the active oxidizing species, combining reversibly with the substrate to form a complex whose subsequent decomposition gives the principal reaction products. The very small equilibrium concentration of sulphur tetroxide becomes the limiting factor in the rate of oxidation when a readily oxidizable substrate is present in relatively high concentration. The mechanism is applied to the data of Eager and Winkler for the oxidation of mercaptans, in which a limiting rate was attained above a certain mercaptan concentration. An empirical equation relating the rate constant to the mercaptan concentration is developed to fit the experimental data. Rate equations showing the rate dependence on mercaptan concentration are derived from the proposed mechanism and are found to be of the same form as the empirical equation. The mechanism is applied also to the persulphate oxidation of water.

ISSN:0008-4042    

DOI:10.1139/v53-122

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

A series of hydrogen chloride catalyzed reactions involving cyanogen iodide as the starting material have been investigated in dioxane and in aqueous solution at 30°and 45 °C. The course of the reaction was followed by determining the decrease in the number of oxidation equivalents present. Reaction products identified were: iodine monochloride, iodine, ammonium chloride, and carbon dioxide. A possible reaction mechanism has been suggested.

ISSN:0008-4042    

DOI:10.1139/v53-123

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

The thermal decomposition ofn-butane at 442 °C.has been investigated analytically in the pressure range 4–13 cm. Up to 9% decomposition, the rates of formation of H2, CH4, C2H4, and C2H6are independent of time; the dependence of the rates on butane pressure was approximately first order. The validity of the extrapolation procedure for obtaining the initial products was established, there being no significant variation in the composition of the products with extent of decomposition. In the nitric oxide fully inhibited reaction irreproducible rate data were obtained although the proportions in which the products are formed seemed to be roughly invariable. In view of this it is suggested that no very definite conclusions can be drawn from a comparison of the composition of the products of the normal and fully inhibited reactions. The heterogeneity of the fully inhibited reaction is stressed for the importance of this has not hitherto been sufficiently recognized. Attention is drawn to the apparent inefficiency of nitric oxide as an inhibitor.

ISSN:0008-4042    

DOI:10.1139/v53-124

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

Reaction of tri-O-acetyl-D-glucosanwith 1,2,3,6-tetra-O-acetyl-β-D-glucose at 120 °C. for 13 hr. followed by acetylation and then chromatographic separation of the products afforded octa-O-acetyl-β-D-maltose in about 8% yield.

ISSN:0008-4042    

DOI:10.1139/v53-125

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

The alkaloid hitherto described as obscurine has been shown to consist of a mixture of two bases, α-obscurine (C17H26ON2) and β-obscurine (C17H24ON2). Dehydregenation of α-obscurine by heating with palladium-charcoal gives rise to 7-methylquinoline and 6-methyl-α-pyridone. The infrared absorption spectrum of the base shows absorption bands indicative of a carbony and of a secondary amino group, possibly in a cyclic lactam, while absorption in the ultraviolet indicates the presence of a double bond conjugated with the carbonyl group. β-Obscurine on the other hand contains an α-pyridone ring as shown by its infrared absorption spectrum and also by the similarity of its ultraviolet absorption spectrum with that of 6-methyl-α-pyridone.

ISSN:0008-4042    

DOI:10.1139/v53-126

出版商:NRC Research Press    

年代:1953

数据来源: NRC

摘要:

After the removal of gelsemine and sempervirine from the extract of the root ofGelsemiumsempervirensAit. the residual alkaloids left in the mother liquors were benzoylated. It was thus possible to separate the tertiary bases from the secondary bases which were obtained as a mixture of the neutral benżoyl derivatives. Purification by chromatography yielded the benzoylated mixture in crystalline form. This was hydrolyzed and the recovered secondary bases were separated by fractional crystallization of the perchlorates into alkaloid A and alkaloid B. Alkaloid A was shown by direct comparison to be identical with the gelsemicine (C20H26O4N2) of Chou. Alkaloid B, now designated gelsedine, was shown to be distinct from either gelsemicine or gelsemine. It appears to be identical with the alkaloid C19H24O3N2claimed by Janot and his co-workers to be gelsemicine. From the tertiary bases there was isolated an apparently new base, gelseverine, as its crystalline perchlorate. Whereas gelsemine is a 3,3-disubstituted oxindole, gelsedine appears to be a 1,3-disubstituted oxindole and gelseverine a 1,3,3-tri-substituted oxindole. Gelsemicine shows many of the characteristics of an indole alkaloid

ISSN:0008-4042    

DOI:10.1139/v53-127

出版商:NRC Research Press    

年代:1953

数据来源: NRC