摘要:

AbstractBenzylation of 6‐methylthiopurine (I) and its N‐alkyl derivatives in an aprotic solvent usually leads to a single reaction product. Both (I) and its 7‐benzyl derivative are attacked at N‐3, in analogy to the behavior of the corresponding 7‐methylpurine. Reaction of the 9‐benzyl derivative of (I), followed by thiohydrolysis of the thioether group, gives 7, 9‐dibenzyl‐6‐thiopurine betaine. This result is in disagreement with an earlier report that the 9‐methylderivative is substituted by methyl iodide at N‐3. Re‐investigation shows, however, that in this case too, the 9‐alkyl group directs further attack toward N‐7. Methylation and benzylation of (I) thus

ISSN:0021-2148    

DOI:10.1002/ijch.196700044

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY

摘要:

AbstractIsobutyraldehyde, propionaldehyde and acetaldehyde have been found to react with benzamide in the presence of napthalenesulfonic acid to give an enamide, two dimeric enamides and a probably polymeric mixture, respectively. The same products were also obtained from the corresponding alkylidenebisbenzamides (I) under acidic conditions.

ISSN:0021-2148    

DOI:10.1002/ijch.196700045

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY

摘要:

AbstractTransformation of some chalcone bromohydrins and their acetates under different conditions are described.

ISSN:0021-2148    

DOI:10.1002/ijch.196700046

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY

摘要:

AbstractA kinetic study of the solvolysis and rearrangement ofp‐methoxybenzyl arenesulfinates was made. In contrast to the sulfur‐oxygen bond fission mechanism which prevails for benzyl arenesulfinates, a carbon‐oxygen bond fission by an ionization mechanism was found for the correspondingp‐methoxybenzyl

ISSN:0021-2148    

DOI:10.1002/ijch.196700047

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY

摘要:

AbstractCatechol oxidase from apple chloroplasts and browning of apple slices are strongly inhibited by the chloride anion. The inhibition is non‐competitive and reversible. Inhibition is pH‐dependent. being observed at pH 5.1 but not at pH 7.3. Activity could be extracted from the particles using CTAB. The extract's activity at the two pH could not be resolved into distinct fractions. The pH‐dependence of inhibition is ascribed to a change in the tertiary structure of the e

ISSN:0021-2148    

DOI:10.1002/ijch.196700048

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY

摘要:

AbstractA method is presented for a simple and direct determination of gold in alloys, utilizing a preliminary separation of gold from an alloy, and its subsequent conversion to chloroauric acid.The optical density of the chloroaurate ion is measured at two selected wavelengths, calculating the gold content of alloys by using the absorbance difference technique as developed by Glasner and Avinur. A suitable technique enables wide‐range determination in various samples of gold alloys ranging from 0.001% to over 90% gold content. Platinum does not interfere when present in small amounts in the allo

ISSN:0021-2148    

DOI:10.1002/ijch.196700049

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY

摘要:

AbstractA pH‐spectrophotometric study of the Ti‐tiron complex in the presence of Ca ions revealed the existence of mixed compounds of Ca‐Ti‐tiron. These could account for the interference of Ca in the determination of Ti by tiron. The formation of these mixed compounds under varying concentrations of components and at varying pH is discussed. The absorbance of the Ti‐tiron was likewise studied in the presence of many colorless salt solutions, but the behavior of Ca was found to be unique. Use was made of the color of the mixed compounds of Ca‐Ti‐tiron to develop a method for the identification of small amounts of Ca in the presence of large quantities of many

ISSN:0021-2148    

DOI:10.1002/ijch.196700050

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY

摘要:

AbstractThe effect of varying concentrations of neutral salts on the initial pH of maximum color in the colorimetric determination of Ti by tiron was studied. A direct method was developed for the determination of Ti in the presence of great amounts of Ca and Fe. The various reducing or masking agents used for the prevention of the interference of iron were discussed. Many ions were found not to interfere, and the limiting tolerance of others was given. The method may find application in the determination of Ti in rocks and alloys.

ISSN:0021-2148    

DOI:10.1002/ijch.196700051

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY

ISSN:0021-2148    

DOI:10.1002/ijch.196700052

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY

ISSN:0021-2148    

DOI:10.1002/ijch.196700053

出版商:WILEY‐VCH Verlag    

年代:1967

数据来源: WILEY