摘要:

Various porphyrins and chlorophyll derivatives have been purified on a preparative scale by distribution between hydrochloric acid and ether on Celite columns. By this technique crudeChlorobiumpheophorbide (650) was resolved into six components, which possessed almost identical visible absorption spectra, but slightly different acid distribution numbers. Chromic acid oxidation and subsequent gas–liquid partition chromatography of the neutral fractions indicate the presence of more than oneChlorobiumchlorophyll (650) in the original pigment preparation.

ISSN:0008-4042    

DOI:10.1139/v62-029

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The proton magnetic resonance spectra of some pyrrolines and pyrroline oxides have been determined. The spectra accord with the Δ1formulation of the bases.

ISSN:0008-4042    

DOI:10.1139/v62-030

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Triphenylphosphine, triphenylarsine, triphenylstibine, and triphenylbismuthine have been evaluated as acceptors in oxygen transfer reactions involving 1-pyrroline-1-oxides. The first reagent especially offers a useful route from the nitrones to the corresponding pyrrolines.

ISSN:0008-4042    

DOI:10.1139/v62-031

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

It is shown that the open pore volume within carbon blacks can be calculated from nitrogen adsorption isotherms (77°K) on the blacks. From this volume and a helium density, the apparent density of a black can be calculated. Other properties of the blacks which then can be calculated are free surface area, internal surface area, surface roughness factor, and the average pore diameter of the internal surface. These data are presented for five selected carbon blacks.

ISSN:0008-4042    

DOI:10.1139/v62-032

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The photochloriuation of methyl chloride has been studied at 2.4°, 25.0°, and 50.1 °C using absorbed light intensities of the order of 10−10einstein cm−3sec−1and a wave length of 4358 Å. Chain termination was by chlorine atom removal but two mechanisms were operative. For the first, termolecular collisions, the evidence indicated somewhat different third-body efficiencies for methyl chloride, methylene chloride, and chlorine; the efficiency of SF6was lower than for these by a factor of 6 to 9; the efficiency of HCl was, relatively, too small to measure. The second mechanism involved "sticky" collisions. Methylene chloride was particularly efficient in this process, indicating an unusually stable CH2Cl2–Cl complex.

ISSN:0008-4042    

DOI:10.1139/v62-033

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The empirical bond energy scheme described in Part I has been modified and applied to saturated and aromatic ring compounds. The classes of compounds treated are the alkyl benzenes, alkyl cyclopentanes, and alkyl cyclohexanes. The scheme given permits values for the heats of atomization, formation, combustion, and vaporization to be calculated. Reasons for the failure of the scheme, when applied to aromatic nuclei containing a functional group, are discussed.

ISSN:0008-4042    

DOI:10.1139/v62-034

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The preparation and properties of 3-keto-1,2,5,6-tetrahydro-3(H)-imidazo(1,2-a)imidazole, 3-keto-1,2,6,7-tetrahydro-3(H),5(H)-imidazo(1,2-a)pyrimidine, and 4-keto-2,3,6,7,8,9-hexahydro-4(H)-pyrimido(1,2-a)pyrimidine are described. The first two bicyclic systems possess active methylene groups in position 2 and they are oxidized to indigo-type dyes.

ISSN:0008-4042    

DOI:10.1139/v62-035

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

No 4-phenylpyridine is formed in the reaction of phenyllithium with pyridine. When phenyllithium reacts with a 3-alkylpyridine the main product is the 3-alkyl-2-phenylpyridine if the alkyl group is methyl, ethyl, or isopropyl, but it is the 5-alkyl-2-phenylpyridine when the substituent ist-butyl. Methods are described for the separation and quantitative analysis of mixtures of 3-alkyl- and 5-alkyl-2-phenylpyridines using vapor phase chromatography. The results are discussed briefly and possible explanations of the observed orientations are mentioned.

ISSN:0008-4042    

DOI:10.1139/v62-036

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Allyl 9-fluorenyl sulphide, benzyl 9-fluorenyl sulphide, and di-9-fluorenyl sulphide are stable to boiling ethereal phenyl lithium, in marked contrast to the corresponding ethers. Benzyl 9-fluorenyl sulphoxide has been prepared and shown to be more weakly acidic than 9-fluorenyl sulphones.

ISSN:0008-4042    

DOI:10.1139/v62-037

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The reactions ofD-xylose, methyl α-D-xylofuranoside, and methyl β-D-xylopyranoside with methanolic hydrogen chloride under controlled conditions have been followed by gas–liquid partition chromatographic analysis of the products. Rate curves were established for each of the four methyl-D-xylosides and the results showed that the following sequence of reactions occurs in the formation of methyl xylosides: (1) xylose → furanosides, (2) anomerization of furanosides, (3) furanosides → pyranosides, (4) anomerization of pyranosides. The relative rates of these four reactions in order of decreasing velocity are 2, 1, 3, 4. Reaction 3 appears to proceed with retention of configuration at the anomeric center. Possible intermediates in these reactions are discussed. Substitution of positions 2 and 3 in theD-xylose molecule byO-methyl groups resulted in an increase in the furanoside content of the methanolysis products at equilibrium.

ISSN:0008-4042    

DOI:10.1139/v62-038

出版商:NRC Research Press    

年代:1962

数据来源: NRC