摘要:

AbstractThe formyl carbonyl group in bis(4‐methoxyphenyl)‐acetaldehyde does not contribute to the formation of the carbonyl group in 4,4′‐dimethoxydeoxybenzoin when the former rearranges to the latter by treatment with 50% (w/w) sulfur

ISSN:0018-019X    

DOI:10.1002/hlca.19760590202

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Complex Formation of Ionophores of the Dioxaoctane Dicarboxylic Acid Diamide Type with Alkali and Alkaline Earth Cations. Stability Constants in Ethanol.Stability constants are reported for two noncyclic, neutral ionophores in interaction with alkali and alkaline earth metal cations in ethanol. The ligands studied give high selectivity of alkaline earth in respect to alkali metal cations when used in liquid membrane electrodes.

ISSN:0018-019X    

DOI:10.1002/hlca.19760590203

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Planar Pt(II)‐ and Pd(II)‐Complexes with Terdentate Azo‐ and Azomethine Ligands: A Contribution to the Question of Nα/Nβ‐Isomerism.The preparation and properties of novel Pt(II)‐ and Pd(II)‐complexes with terdentate azo‐ and azomethine ligands and with an amine in the fourth coordination position of the metals are described. In certain cases the formation of isomeric complexes is observed, which are interpretated as Nα/Nβ‐isomers according to their1H‐NMR.‐signals.The postulated isomerism will be proved by15N‐NMR.‐spectroscopy – in the following publication [5] using15N‐enriched compounds whose syntheses ar

ISSN:0018-019X    

DOI:10.1002/hlca.19760590204

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe15N‐NMR. parameters of some Pt(II)complexes of unsymmetricalo,o′‐dihydroxydiarylazo‐ligands are shown to be useful in the solution of subtle structural p

ISSN:0018-019X    

DOI:10.1002/hlca.19760590205

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Some comments on the synthesis of 3‐aminotoluene‐5‐sulfonic acid and 2‐aminotoluene‐3‐sulfonic acid.Sulfonation of 3‐nitrotoluene (5) yields predominantly the unsymetrical isomer 5‐nitrotoluene‐2‐sulfonic acid (7), and lesser amounts of 5‐nitrotoluene‐3‐sulfonic acid (6), previously reported as the major product. The desired 5‐aminotoluene‐3‐sulfonic acid (3) was synthesized in preparative amounts from 6‐aminotoluene‐3‐sulfonic acid (4)viathe following sequence of reactions: diazotation andSandmeyerreplacement of 6‐chlorotoluene‐3‐sulfonic acid (13), nitration of the sulfonyl chloride14under suitable conditions to give isomer free 6‐chloro‐5‐nitrotoluene‐3‐sulfonyl chloride (15), hydrolysis to the sulfonic acid16and finally, simultaneous hydrogenolysis and reduction to3. The isomeric7was unequivocally prepared from 2‐amino‐5‐nitrotoluene (9)viatwo routes: (1) diazotation,Sandmeyerthiocyanatation to 5‐nitro‐2‐thiocyanatotoluene (10), Na2S reduction to the di(2‐methyl‐4‐nitro‐phenyl)‐disulfide (11), treatment with nitric acid and chlorine to give 5‐nitrotoluene‐2‐sulfonyl chloride (12) and finally alkaline hydrolysis to7; (2)Meerwein'sSO2treatment of the diazonium salt derived from9leads directly to12and thence to7.2‐Aminotoluene‐3‐sulfonic acid (1) was prepared from the key intermediate 3‐amino‐2‐nitrotoluene (18)viathe same two routes used to prepare7from9. Both reaction sequences provided 2‐nitrotoluene‐3‐sulfonly chloride, the hydrolysis product of which was reduced to1. Intermediate18was prepared in the following four steps fromm‐toluic acid (19): nitration to the 2‐nitroderivative (2

ISSN:0018-019X    

DOI:10.1002/hlca.19760590206

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractA Synthesis of vitamin A has been achieved by alkylating a β‐ionylidene‐ethyl (C15) aromatic sulfone with 1‐acetoxy‐3‐chlormethyl‐2‐butene (C5) followed by elimination of the corresponding

ISSN:0018-019X    

DOI:10.1002/hlca.19760590207

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

A Synthesis of Vitamin A According to the Sulfone Method.Starting from β‐ionyl phenyl sulfone7and an appropriate allylic chloride10retinol14has been prepared by a direct procedure. Subsequent acetylation and isomerization led to crystalline all‐E‐vitamin A ace

ISSN:0018-019X    

DOI:10.1002/hlca.19760590208

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Detection of Fragment Genesis in the Mass Spectrometer. III. Analysis of Amino‐Acid Sequence in Oligopeptides and in Mixtures of Oligopeptides by DADI‐Mass Spectrometry.The amino acid sequence was analysed by DADI mass spectrometry in simple oligopeptides and in mixtures containing two or three pepti

ISSN:0018-019X    

DOI:10.1002/hlca.19760590209

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

Photolysis of Bicyclo[3.3.1]nonan‐2‐one.Disproportionations, the secondary processes available to the acyl‐alkyl biradicalb(X(9) = 0) formed from 9‐oxabicyclo[3.3.1]‐nonan‐2‐onesa(X(9) = 0) in a primary photochemical process by α‐cleavage (Norrishtype I cleavage) were studied. Special attention was paid to the selectivity between the two possible H‐abstractions: the one at C(3) (→ ketenec, X(9)= 0) and the other one at C(8) (→ alkenald, X(9) = 0) and to the selectivity of the H‐abstraction at a definite methylene group (C(3) or C(8)). In the case of ketene formation (→c, X(9) = 0) the specificity of the insertion of the migrating H‐atom at C(1) was studied.endo‐6‐Hydroxy‐9‐oxabicyclo[3.3.1]nonan‐2‐one (6) and derivatives of it (7, 8, 16, 17, 19, 21, 30and38) as well asexo‐6‐hydroxy‐9‐oxabicyclo[3.3.1]‐nonan‐2‐one (41) and its derivative42were used as substrates.UV.‐irradiation of6in benzene yielded 1,5‐dioxa‐2‐cis‐decalone (44) by way of a keteneg(R = H) as demonstrated by the photolysis of7(→45),8(→43), and17(→47). Specific labellings with deuterium proved that H‐abstraction occurs intramolecularly at C(3) (e.g.16→54;6+16→44+54), that one of the H‐atoms at C(3) migrates specifically to C(1) (21→55;19→56),endo‐H–C(3) being favored by a factor of 6. The abstraction showed an unexpected primary isotope effect of about 2.UV‐irradiation of41in benzene yielded in addition to the expected 1,5‐dioxa‐2‐trans‐clecalone (63) about 3% of an isomeric co

ISSN:0018-019X    

DOI:10.1002/hlca.19760590210

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

The Synthesis of 2,2′‐Dinor‐carotenoids.2,2′‐Dinor‐carotenoids which include the naturally occurring actinioerythrol (1) and the blue carotenoid violerythrin (2) have been obtained by total synthesis. The synthesis starts with acetone and acetylene and yields compounds1and2as well as other carotenoids of th

ISSN:0018-019X    

DOI:10.1002/hlca.19760590211

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY