摘要:

AbstractQuaternary 1,2,4‐triazolium salts1couple easily with p‐N,N‐dimethylamino‐benzenediazonium salts to form azodyes3(5‐N,N‐dimethylaminophenylazo‐1,2,4‐triazolium salts), preferably under solid‐liquid phase transfer conditions using chloroform or methylene chloride and triethylamine or DABCO.Zwitterionic 1,2,4‐triazolium salts anhydro mercapto hydroxide, anhydro hydroxy hydroxide, and anhydro anilido hydroxide („nitron”︁) couple as well.The azodyes — as also well known from industrially used types — absorb in the region of 500 nm and have high extinction coefficients.Substituents in 1‐, 3‐ or 4‐position of the triazolium ring exert no clear substituent effects.The quaternary 1,2,4‐triazolium salts were synthes

ISSN:0021-8383    

DOI:10.1002/prac.19883300302

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

Fission of 1,2,4‐Thiadiazol‐3‐ones by Triphenylphosphane: gewidinet Triphenylphosphonio Thioimidazolates and Their Consecutive ReactionsTreatment of benzimidazo[1,2‐d][1,2,4]thiadiazol‐3(2H)‐ones (1) and imidazo[1,2‐d]‐[1,2,4]thiadiazol‐3(2H)‐ones (17) with triphenylphosphan leads to the liberation of isocyanate and the formation of triphenylphosphonio‐thiobenzimidazolat (4) and triphenylphosphonio‐thioimidazolat (18), respectively. 2,4‐Diphenyl‐5‐phenylimino‐1,2,4‐thiadiazol‐3‐one (23) is desulfurized with Ph3P and decomposed into phenyl isocyanate and diphenylcarbodiimide whereas the N‐unsubstituted imino‐thiadiazol‐3‐one (25) is attacked at the exocyclic imino group by Ph3P to give the N‐phosphoranylidene thiourea (26). The structure of4can be rationalized as a dynamic system between polar and apolar valence isomeres. Reactions of1and17with cyanates, isocyanates, carbon disulfide, acetic anhydride, amines, benzyl chloride, grignard c

ISSN:0021-8383    

DOI:10.1002/prac.19883300303

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

Relation between Structure and Properties of Ring Halogenated p‐Dimethylamino‐benzene Diazonium Salts, I.R. and U.V.‐Vis. Spectroscopical Behaviour and PhotolysisThe relation between the molecular structure of the halogene substituted p‐dimethylaminobenzene diazonium salts p‐DABS‐1, 1a–kand their i.r.‐ u.v.‐vis.‐spectroscopic and photochemical properties has been investigated. The N–N stretching frequencies and intensities of1, 1a–kare linearly correlated with special Hammett ΣσR‐constants of the substituents. The u.v.‐vis. spectra of the sterically hindered compounds show a red shift of the absorption maxima together with a strong decrease of the absorption intensity. The angle of twisting between the dimethylamino group and the ring plane has been estimated.From the spectroscopic data the mesomeric, inductive and steric effects of the substituents in the ring of the p‐DABS can be estimated in a quantitative way. The quantum yields of the photolysis of the p‐DABS (λE= 405 nm) were determined in 0,1 n H2SO4and dioxane/0,1 n H2SO4(1:1, v/v) in the presence and absence of oxygene. In the sensitized photolysis of selenopyronine (λE= 578 nm) a linear correlation of the quantum yields (lg Φ) and special Σσcorr‐constants are observed. The sensitized photolysis of the polyhalogenated p‐DABS1

ISSN:0021-8383    

DOI:10.1002/prac.19883300304

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

Furylvinylhalides. IX. Reactions of β‐fur‐2‐yl‐β‐chloro‐α‐cyanoacrylates with aminesβ‐Fur‐2‐yl‐β‐chloro‐α‐cyanoacrylates4react with amines to yield β‐Fur‐2‐yl‐β‐amino‐α‐cyan

ISSN:0021-8383    

DOI:10.1002/prac.19883300305

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

On the Transmission of Substituent Effects in Fluorenes and FluorenonesA series of 2‐ and 2,7‐substituted fluorenes (1) and fluorenones (2) were prepared either by electrophilic substitution (1c–f, h–j; 2c, d, j), reduction (1, 2k, l) or nucleophilic exchange (1g, m, n; 2m) via respective diazonium compounds as well as by oxydation (2e–h, n) of the hydrocarbons (1).The carbon‐13 n.m.r. spectra for the fluorene (1a–n) and fluorenone (2a–n) derivatives was analyzed using a dual substituent parameter (DSP) equation. The substituent chemical shifts (SCS) of the carbon atoms 4a, 4b, 7 and 4a, 4b, 7, 9 of eleven fluorenes and nine fluorenones, respectively, correlate with the

ISSN:0021-8383    

DOI:10.1002/prac.19883300306

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

Ring Opening of 2‐Oxocyclohexane Carboxamide to 2‐Hydroximinopimelic‐1‐amideReaction of 2‐oxocyclohexane carboxamide (1) and sodium nitrite in 1n hydrochloric acid yields 2‐hydroximinopimelic‐1‐amide (2).2and dimethylsulphate react to give compounds3and4, respectively,2and 1.6‐diamino hexane form salt5, 2and cyclohexanone (resp. cyclopentanone) yield imidazoline‐N‐oxide6(and7, resp.)2and hydrazine afford

ISSN:0021-8383    

DOI:10.1002/prac.19883300307

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

Synthesis of Heterocyclically Substituted‐4‐Piperidinyl‐1,4‐dihydropyridines by Ring Closure Reactions at a N‐Acylthioamide‐ or at a N‐Acylisothioamide‐Side‐GroupA series of 4‐(2′‐methylenepiperidin‐4′‐yl)‐1,4‐dihydropyridines [5–7and9–11] with a heterocyclic substituent at the methylene group is prepared by reaction of the nonsubstituted compound1with benzoylisothiocyanate or ethoxycarbonylisothiocyanate to the N‐benzoylthioamide2or the N‐ethoxycarbonylthioamide3, transformation of2into the isothioamide4by S‐methylation, and subsequent ring closure of2, 3or4with hydrazine, methylhydrazine, phenylhydrazine, 1,2‐diaminoethane, 1,2‐ and 1,3‐d

ISSN:0021-8383    

DOI:10.1002/prac.19883300308

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

AbstractThe VIS‐laser irradiation of enol lactones1a, band benzoquinone in an argon atmosphere led to the fenestrane‐type oxetane2aand the propellane‐type oxetane2b, with regioselective preference for the acetal structure. Under an oxygen atmosphere both regioisomeric fenestrane‐type 1,2,4‐trioxanes4aand5awere obtained from enol lactone1a, while no oxygen trapping to the propellane‐type trioxanes was observed with1b. Significant quantities of photooxygenation products were obtained from both enol lactones1a, bdue to singlet oxygen derived from oxygen quenching of benzoquinone triplets. The present study demonstrates that Qinghaosu analoga are accessible via trapping of Paterno‐Büchi triplet 1,4‐diradicals by

ISSN:0021-8383    

DOI:10.1002/prac.19883300309

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

Photochemistry of Diarylsubstituted 2H‐Tetrazoles. VI. Quantumyields of the Photolysis of Diarylsubstituted 2H‐TetrazolesThe photoexcitation of diarylsubstituted 2H‐tetrazoles in ethanol in the presence of methylmethacrylat (MMA) yields quantitatively 1,3‐diaryl‐Δ2‐pyrazolines. The photoreactions investigated are spectroscopically uniform. The influence of the substituents on the quantum yields of the photolysis of 2H‐tetrazoles (1a—

ISSN:0021-8383    

DOI:10.1002/prac.19883300310

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY

摘要:

Abstract6‐Arylpyridazin‐3(2H)‐thiones (1a—c) react with Grignard reagents by 1,4‐addition to give either 4‐substituted 6‐aryl‐4,5‐dihydropyridazin‐3(2H)‐thiones (2a—c) or their dehydrogenated products, namely 4‐substituted 6‐arylpyridazin‐3(2H)‐thiones (3d—k). The reaction of Grignard reagents with 6‐aryl‐4‐methylpyridazin‐3(2H)‐thiones (3d—f) proceeds also by 1,4‐addition yielding 4,4‐disubstituted 6‐aryl‐4,5‐dihydropyridazin‐3(2H)‐thiones (5). Structural assignments are based on analytical and spectral data a

ISSN:0021-8383    

DOI:10.1002/prac.19883300311

出版商:WILEY‐VCH Verlag GmbH    

年代:1988

数据来源: WILEY