摘要:

AbstractPhenols containing a freeortho‐position can be alkylated byortho‐t‐butyl‐phenols in the presence of catalytic amounts of aluminium phenoxide at temperatures between about 120° and 170°.Using 2‐t‐butylphenol, 2,6‐di‐t‐butyl‐phenol or ‐p‐cresol as the alkylating agent, trans‐t‐butylations were carried out with the following phenolic acceptors: phenol,o‐,m‐,p‐cresol,p‐Br‐,p‐Cl‐,p‐F‐,p‐CH3O‐,p‐t‐Bu‐,p‐isoPr‐, andp‐Et‐phenol. Higher rates were observed for the more acidic phenols.The above mentioned reactions lead to equilibria of the type: 2,6‐di‐t‐butyl‐p‐Z‐C6H2OH +p‐Z‐C6H4OH ⇄ 2 2‐t‐butyl‐p‐Z‐C6H3OHThe equilibrium constant for this reaction is about 24 and independent of the substituent in the phenolic nucleus.For Z = CH3the energy of activation has the value 36 (± 3) kcal/mole.When the 3, 4 and 5 positions are unoccupied, a slowortho‐paraisomerization takes place along withortho‐trans‐t‐butylation.The equilibrium between 2‐t‐butylphenol and 4‐t‐butylphenol lies far towards the thermodynamically more stablepara‐isomer, theortho‐isomer however is kinetically more favourable.Meta‐isomers are formed under these conditions to a small extent and only after long reaction times.At temperatures above 140° some dealk

ISSN:0165-0513    

DOI:10.1002/recl.19710900102

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractPhenols containing a freeorthoposition can be alkylated byortho‐t‐butyl‐phenols in the presence of catalytic amounts ofp‐toluenesulfonic acid at temperatures between ∼ 60 and 100°.Using,e.g., 2,6‐di‐t‐butyl‐p‐cresol as an alkylating agent, trans‐t‐butylations were carried out with a number ofpara‐ andortho‐substituted phenols.The above mentioned reactions lead to equilibria of the type: 2,6‐di‐t‐butyl‐p‐ZC6H2OH +p‐ZC6H4OH ⇄ 2 (2‐t‐butyl‐p‐ZC6H3OH)The equilibrium constant (K= 43 at 80°C) is independent of the substituent present in the phenolic nucleus.For Z =p‐CH3the energy of activation of the forward reaction amounts to 18.5 kcal/mole.Ortho‐paraisomerization occurs, when the 3, 4 and 5 positions are free. Several differences between the catalytic effects o

ISSN:0165-0513    

DOI:10.1002/recl.19710900103

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractProduct distributions and rate data of the thermal decomposition of a diazothiolate (Ar‐NNSR) in benzene, chlorobenzene and nitrobenzene as a function of initial diazothiolate concentrations show the reaction to be complex. Three different types of radical‐induced decomposition are di

ISSN:0165-0513    

DOI:10.1002/recl.19710900104

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe synthesis of 6‐dehydro‐9β, 10α‐progesterone (IV) from progesteroneviairradiation of 3,20‐bis(ethylenedioxy)pregna‐5,7‐diene (II) is described. An analogous synthesis has been accomplishedvia3‐(ethylenedioxy)pregna‐5,7‐dien‐20‐one (VI).Pyrolysis of the 9,10‐seco‐bisacetal (IX), a vitamin D analogue, followed by hydrolysis and isomerization, gave the 8α,10α‐isome

ISSN:0165-0513    

DOI:10.1002/recl.19710900105

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19710900106

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractOxidation of the isomeric cyclopentadithiophenes by oxygen in the presence of potassiumt‐butoxide int‐butanol‐dimethyl sulfoxide (4 : 1), or Triton B in pyridine, caused a cleavage reaction to occur and gave the corresponding bithienylcarboxylic acids. In contrast, the dithienylmethanes gave the corresponding dithienyl ketones. The Michael reaction of 7H‐cyclopenta[1,2‐b: 4,3‐b′]dithiophene with acrylonitrile is a

ISSN:0165-0513    

DOI:10.1002/recl.19710900107

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe cleavage reactions of non‐enolizable thienyl ketones have been studied. Potassiumt‐butoxide int‐butanol, ether or dioxane has proved to be a mild cleavage reagent. With most ketones high yields of acids were obtained after a short reaction time at room‐temperature. Possible mechanisms for these mild reactions and theHaller‐Bauercleavage of thienyl ketones are

ISSN:0165-0513    

DOI:10.1002/recl.19710900108

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractUsing X‐ray reflection intensities collected with a single crystal, the crystal structure of MnNb4S8has been determined. The position of Mn is uniquely defined. The difficulties arising in space group determination and crystal structure refinement are discussed in some detail; the most essential structural features are presented and compared with those of MnNb3S

ISSN:0165-0513    

DOI:10.1002/recl.19710900109

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractContrary to literature data 1‐isopropylcyclohexanol afforded both 1‐isopropylcyclohexanecarboxylic acid and 2‐cyclohexyl‐2‐methylpropanoic acid upon carboxylation by the method ofKoch.The Koch‐Haaf carboxylation of a number oftert‐alkyl substituted cycloalkane derivatives has been studied. Side reactions were suppressed by using the Haaf conditions with slow stirring of the reaction mixture.tert‐Butylcyclohexanols afforded 1‐tert‐butylcyclohexanecarboxylic acid accompanied by 2‐methyl‐2‐(1‐methylcyclohexyl)propanoic acid. In the Koch‐Haaf reaction of 3‐tert‐butylcyclopentanol and 4‐tert‐butylcycloheptanol more complex rearrangements occurred. The main products were 1,2,2‐trimethylcyclohexanecarboxylic acid and 2‐cyclohexyl‐2,3‐dimethylbutanoic acid, respectively.From the composition of the reaction products conclusions were drawn concerning the mechanisms of the rearrangements involved in these reactions. In some of the reactions protonated cyc

ISSN:0165-0513    

DOI:10.1002/recl.19710900110

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractEnthalpies of solution of alkali halides in formamide,N‐methylformamide,N, N‐dimethylformamide,N‐methylacetamide, dimethyl sulfoxide, water, methanol and ammonia are discussed. The ensuing enthalpies of transfer between any two solvents are nearly constant for salts with a common anion. The enthalpies of solution of a single salt in the different liquids can be correlated with the structure of the so

ISSN:0165-0513    

DOI:10.1002/recl.19710900111

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY