ISSN:0165-0513    

DOI:10.1002/recl.19800990902

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractTexture studies, in which specific surface area and total pore volume were determined by low temperature nitrogen adsorption, were carried out on a number of porous solids, ranging from cation‐exchanged Y‐zeolites, impregnated with β‐AlF3and copper, to steamed silica‐alumina. The zeolites were impregnated with β‐AlF3and Cu in order to improve their Toluene disproportionation performance.After comments on the applicability of the conventional approaches to zeolites and zeolite‐containing solids, a new method is proposed for calculating of the surface area of this class of compounds. This method makes use of the micropore volume, determined byDe Boer's t‐method, and the surface area and volume of a zeolite cage, calculated

ISSN:0165-0513    

DOI:10.1002/recl.19800990903

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractReaction of 6‐chloro‐ and 6‐(methylthio)purine with potassium amide in liquid ammonia leads to the formation of adenine. When these aminations are carried out with15N‐labelled potassium amide, the15N label is found to be present in the amino group, proving that these reactions do not involve opening of the pyrimidine ring. Low temperature1H‐ and13C‐NMR spectroscopy of solutions of 6‐chloro‐ and 6‐(methylthio)purine in liquid ammonia, containing potassium amide give no evidence for the presence of an intermediary σ‐adduct. 8‐Chloro‐ and 8‐(methylthio)purine undergo a Tschitschibabin amination at position 6 leading to 8‐chloro‐ and 8‐(methylthio)adenine. In addition 8‐chloropurine gives adenine. Evidence is presented that the formation of this product proceedsviaatele‐amination. 6‐tert‐Butyl‐8‐(methylthio)purine and 8‐aminopurine are

ISSN:0165-0513    

DOI:10.1002/recl.19800990904

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractDichlorocarbene, generated from base‐catalysed decomposition of chloroform, adds to the double bond of 2‐methylisoquinolin‐1‐one (1), to give the 1:1 adduct (2). The latter adduct reacts with water to giveE‐3‐(formylmethylene)‐2‐methylisoindolinone (3a). Refluxing of2in alcohols yields alkoxybenzazepin‐1‐ones. Upon heating (of2) in dimethoxyethane and subsequent reduction with lithium borohydride, 4‐chloro‐2‐methyl‐1H‐2,3‐dihydro‐2‐benzazepinone (10) was obtained as the main product. Mechanisms for the format

ISSN:0165-0513    

DOI:10.1002/recl.19800990905

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractIn a two step reaction, hexamethylbenzene consumes two molecules of singlet oxygen to form epidioxy hydroperoxide3. The first step involves a [4 + 2]‐cycloaddition, which is followed by an ene‐reaction. The structure of the intermediary endoperoxide2has been established spectroscopically. Pentamethylbenzene reacts in the same way with singlet oxygen, albeit much more slowly. Two epidioxy hydroperoxides are formed in this c

ISSN:0165-0513    

DOI:10.1002/recl.19800990906

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe α‐chloronitroso compounds1a–1fwere made to react with methyl and phenyl Grignard reagents. N‐methyl and N‐phenyl substituted ketonitrones2and3were obtained in 48‐78% yield. The structure of these labile nitrones is based on their spectroscopic properties and on the formation of characteristic 1,3‐cycloadducts with phen

ISSN:0165-0513    

DOI:10.1002/recl.19800990907

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractFrontier molecular orbital theory has been applied to the [4 + 2]‐cycloaddition of singlet oxygen, to mono‐ and dimethylnaphthalenes and to a number of other polycyclic aromatic compounds. Semilogarithmic plots of rate constants versus second order perturbation energies are found to be linear. The good correlations are due partly to the fact that singlet oxygen is such a small dienoph

ISSN:0165-0513    

DOI:10.1002/recl.19800990908

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe synthesis of several peptides related to β‐LPH‐(62–77) but shortened from theN‐terminal end, is described. In these syntheses use has been made of the classical fragment condensation

ISSN:0165-0513    

DOI:10.1002/recl.19800990909

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractSeveral La(III)‐(hydroxy) carboxylate complexes in aqueous medium have been studied by means of139La chemical shift and line‐width measureme

ISSN:0165-0513    

DOI:10.1002/recl.19800990910

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19800990901

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY