bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iodierung von N‐Aryl‐2,4‐dimethyl‐buta‐1,3‐dien‐1,4‐sultamen
Authors: Fanghänel E. , Mohammed H. , Richter A. M. , Radeglia R. 
Published: December 2004

Iodation of N‐Aryl‐2,4‐dimethyl‐buta‐1,3‐dien‐1,4‐sultamesBy the iodation of N‐aryl‐2,4‐dimethyl‐buta‐1,3‐dien‐1,4‐sultames 1 with I2/HgO in EtOH/AcOH the 1,2‐thiazine ring is substituted. The monosubstitution occurs on the 1‐position (1a, d) and the disubstitution on the 1,3‐position (3a). By iodine monochloride in CHCl3 the sultames 1a–d were substituted in the (C‐2)‐CH3 group (4a–d), in contrast also to the results of chlorination and bromination of 1. The structure of the products 2, 3, 4 was proved by 13C‐n.m.r. spectroscopic data.
Formylation products of thioamides. XIII. Reaction of N‐(3‐aminothioacryloyl)‐formamidines with amines – Synthesis of Pyrimidine Derivatives
Authors: Knoll Alexander , Liebscher Jürgen 
Published: December 2004

AbstractN‐(3‐Aminothioacryloyl)‐formamidines 3 react with primary amines to give either 4(1H)‐pyrimidinthiones 6 or transaminated N‐(3‐aminothioacryloyl)‐formamidines 5. Alkylation of the latter compounds gives rise to cyclised 6(1H)‐pyrimidinimines 7. The 4(1H)‐pyrimidinthiones 6 can be S‐alkylated to 4‐alkylmercaptopyrimidinium salts 8. Subsequent substitution of the alkylmercapto group of the 8 results in the formation of 4‐aminopyrimidinium salts 9, which can also be obtained starting from the 3 by a reversed reaction sequence that is first by S‐alkylation to 3‐alkylmercapto‐2‐azapentamethinium salts 10 and subsequent reaction with primary amines.
Reversible Photoisomerisierungen an Sulfophthalein‐Indikatorfarbstoffen. IV. Stopped‐Flow‐Untersuchungen zum Mechanismus der baseninduzierten Sultonringöffnung
Authors: Grummt U.‐W. 
Published: December 2004

Reversible Photoisomerizations of Sulfophthalein Indicator Dyes. IV. Stopped Flow Investigations on the Mechanism of the Base Induced Sulton Ring OpeningThe colour formation of rapidly mixed solutions of bromo thymol blue and organic bases in toluene obeys a biexponential rate law. The most probable reaction sequence is: Sulton (colourless) + base ⇌ ring opened H‐bridged complex (λmax ≈ 420 nm) ⇌ H‐bridged ion pair (λmax ≈ 400 nm). Alternative reaction schemes of the same complexity could be ruled out though the underlying kinetic problem is underdetermined. As a generalizing conclusion it is stated that valuable mechanistic and kinetic information may be derived from underdetermined kinetic problems by calculating the ranges of physically meaningful solutions for the unknowns which are compatible with the particular kinetic schemes instead of the unavailable singular solutions.
Eine neue Synthese substituierter 4‐Amino‐1,3‐thiazole
Authors: Evers R. 
Published: December 2004

A New Synthesis of Substituted 4‐Amino‐1, 3‐thiazolesIn the 5‐position substituted 4‐amino‐2‐alkylthio‐1, 3‐thiazoles are prepared in good yields from N‐nitro‐amidino‐dithiocarbamates1and α‐halogen‐carbonylcompounds or chloracetonitrile.1reacts with 1, 3‐dichlor‐acetone under formation of adequate bis(1, 3‐thiazolyl)ketones.According to the same principle the reaction of the dipotassium salt of the N‐nitro‐amidino‐dithiocarbimidic acid7with two equivalents of the α‐halogen‐carbonylcompound yields 4‐amino‐5‐benzoyl‐2‐(benzoyl‐methylthio)‐1, 3‐thiazoles.
Potential anticancer agents. XXVI. Spin Labelled Nitrosoureas
Authors: Baracu Ileana , Dobre V. , Niculescu‐Duvaz I. 
Published: December 2004

AbstractIn order to obtain more information about the in vivo mechanism of action of nitrosoureas, the synthesis of spin labelled nitrosoureas derived from 1‐oxyl‐2.2.6.6‐tetramethyl‐4‐aminopiperidine was undertaken. The synthesis of four spin labelled ureas 4a–4d was reported as well as two spin labelled nitrosoureas:1‐methyl‐3‐(2′.2′.6′.6.′‐tetramethyl‐piperidin‐4′‐yl‐1′‐oxyl)‐1‐nitrosourea(9a) and 1‐(2′‐chloroethyl)‐3‐(2″,2″.6″.6″‐tetramethyl‐piperidin‐4″‐yl‐1″‐oxyl)‐nitrosourea(9b). Their e.s.r. spectra were recorded. None of these compounds proved to be active against L1210.
Tetrathiafulvalene. XXII [1] Redox‐ und spektroskopische Eigenschaften von Tetrathiafulvalenen (TTF) und Tetraselenafulvalenen (TSF) sowie deren Mono‐ und Dikationen
Authors: Schukat G. , Fanghänel E. 
Published: December 2004

Tetrathiafulvalenes. XXII. Redox‐ and Spectroscopic Properties of Tetrathiafulvalenes (TTF) and Tetraselenafulvalenes (TSF) and their Mono‐ and DicationsThe polarographic oxidation potential of TTF is decreased by alkyl‐ and increased by aryl‐substituents. The oxidation potentials of arylated TTF can be correlated with σ+‐constants (σ  0,1). TSF are weaker donors than the respective TTF. Alkyl substitution at TTF causes a bathocromic shift and aryl substitution a hypsochromic shift of the longest wavelength absorption band. In the mono‐ and dications of TTF a bathochromic shift of this absorption band is observed by alkyl‐ as well as aryl‐substituents which is especially pronounced, when the molecule is planar.
Synthesis and reactions of 2‐(p‐chloroanilino)‐5‐ (D‐galacto‐1,2,3,4,5‐pentahydroxypentyl)‐1,3,4‐thiadiazole
Authors: El Ashry El Sayed H. , Nassr Mahmoud A. M. , El Kilany Yeldez , Mousaad Ahmed 
Published: December 2004

AbstractOxidative cyclization of D‐galactose (p‐chlorophenyl)thiosemicarbazone gave 2‐(p‐chloroanilino)‐5‐(D‐galacto‐1,2,3,4,5‐pentahydroxypentyl)‐1,3,4‐thiadiazole (1), whose acetylation afforded 2‐[N‐acetyl‐N‐(p‐chlorophenyl)]‐amino‐5‐(D‐galacto‐1,2,3,4,5‐pentacetoxypentyl)‐ 1,3,4‐thiadiazole (3). Its periodate oxidation of the glycol groups gave 2‐(p‐chloroanilino)‐1,3,4‐thiadiazole‐5‐carboxaldehyde (4), which can be transformed into 1,2‐[2‐(p‐chloroanilino)‐1,3,4‐thiadiazol‐5‐yl]‐1‐hydroxy‐2‐oxoethane. A number of hydrazones of the formyl thiadiazole was prepared and its reduction with sodium borohydride gave 2‐(p‐chloroanilino)‐5‐hydroxymethyl‐1,3,4‐thiadiazole (6), whose acetylation gave a mono‐O‐acetyl derivative (7). Oxidation of the formyl thiadiazole gave 2‐(p‐chloroanilino)‐1,3,4‐thiadiazole (9). The spectral data of the compounds were discussed.
Studien über die Autoxidation von 1‐Phenylbuta‐1,3‐dien und 2‐Phenylbuta‐1,3‐dien
Authors: Blau K. , Voerckel V. , Willecke L. 
Published: December 2004

Studies on the Autoxidation of 1‐Phenylbuta‐1,3‐diene and 2‐Phenylbuta‐1,3‐dieneHydrogenation of the polymeric peroxides formed during the autoxidation of 1‐phenylbuta‐1,3‐diene (1) and 2‐phenylbuta‐1,3‐diene (10) at 50°C in an autoclave yielded 1‐phenylbutane‐3,4‐diol (5) and 2‐phenylbutane‐1,4‐diol (12), respectively.The LiAlH4 reduction of 1‐phenylbuta‐1,3‐diene oxidate (50°C) yielded cinnamyl alcohols (4) as a major product.The oxygen‐containing polymeric products formed along with Diels‐Alder dimers during the oxidation of the title substances at 140°C showed no degradation after subjecting to hydrogenation and are therefore considered as polyethers.
Fotochemische Primärprozesse von Xanthenfarbstoffen. V. Untersuchungen zum Mizelleinfluß auf die fotochemischen Primärprozesse von Erythrosin
Authors: Ortmann W. , Winnig B. , Fanghänel E. 
Published: December 2004

Photochemical Primary Processes of Xanthene Dyes. V. Investigations of the Influence of Micelles on the Photochemical Primary Processes of ErythrosineThe triplet state of erythrosine decays in water solution mono‐ and bimolecularly (k1 = 0,85 · 104 s−1; kbi = 7,6 · 108 l/mol s). As results of the bimolecular triplet decay a half‐reduced and a half‐oxidized form of the dye are observed. The dye ions are localized in the Stern layer of cationic micelles. The triplet state of those dye ions, which are localized individually at micelles, decays only monomolecularly (k = 2,1 · 103 s−1). If two or more dye ions are localized at a micelle, the bimolecular triplet decay takes place during the flash. Anionic micelles have no influence on the triplet decay processes of erythrosine.
13C‐NMR‐spektroskopische Analyse von Gemischen Isomerer Alkyl‐4‐butylmorpholine
Authors: Schiefer H. , Beger J. , Scheller D. , Grossmann G. 
Published: December 2004

13C‐N.M.R. Spectroscopical Analysis of Mixtures of Isomeric Alkyl‐4‐butylmorpholinesMixtures of isomeric alkyl‐4‐butylmorpholines 3 were prepared by the treatment of several 2,2′‐dichloroalkyl ethers 1 (from the chlorination of alk‐1‐enes in the presence of ethylene oxide or propylene oxide) with butylamine and distinguished by 13C‐n.m.r. The distribution of isomers of 3 is not changed in relation to that of 1 except 3g,g′.
Vibronisches Spektralverhalten von Molekülen. VI. Theoretische Untersuchungen zur Molekülgeometrie und Spektroskopie des Perylens
Authors: Gustav K. , Seydenschwanz C. 
Published: December 2004

Vibronic Spectral Behaviour of Molecules. VI. Theoretical Investigations on the Molecular Geometry and Spectroscopy of PeryleneThe theoretical completely‐optimized molecular geometries of perylene are presented for the electronic states S0, S1 and T1. On this basis, the vibronic spectral behaviour in absorption and fluorescence has been calculated within the framework of the CONDON approximation. The results obtained are compared with the experimental S0‐S1 absorption and fluorescence and interpreted. The calculated geometry changes determine the significant active modes responsible for the fine structure of the corresponding spectroscopic transitions.
Bildung von Azoolefinen durch Umsetzung von Hydrazinen mit Amino‐hydroxy‐hydrobenzoxazol
Authors: Bischoff Christian , Schröder Edith 
Published: December 2004

About the Reaction between Hydrazines and Aminohydroxy‐hydrobenzoxazol. Synthesis of AzoolefinesBy the reaction of 1‐hydroxy‐2‐oxocyclohexane‐carboxamide (1) with cyanamide 2‐amino‐7a‐carbamoyl‐3a‐hydroxy‐3a,4a,5,6,7,7a‐hexahydrobenzoxazole (2) is formed. Compound 2 and arylhydrazine‐hydrochloride yield 1‐carbamoyl‐2‐arylazocyclohex‐1‐ene (4a, b). In morpholine azocompounds 4a, b rearrange to hydrazones 5a, b. Compound 2 and hydrazine yield 4‐(2‐carbamoyl‐cyclohexyl)‐semicarbazide (10), 10 forms perhydroquinazoline‐2,4‐dione (11) by oxidation with iodine. 2 and cyanic acid yield the urea derivative 12. 2 and arylamine‐hydrochloride afford the 2‐arylamino‐3a‐hydroxy‐7a‐carbamoyl‐hexahydrobenzoxazoles 13a, b. By fragmentation and “Dimroth‐rearrangement” of 2 tetrahydrobenzoimidazolone, (14) is formed, 12 gives 1‐carbamoyl‐tetrahydrobenzoimidazolone (15). 2 and m‐nitrobenzaldehyde yield “Schiff‐base” 16. 2 and hydroxylamine sulphate form 2′‐amino‐2‐hydroximino‐cyclohexane‐spiro‐5′‐oxazolin‐4′‐one (18) 18 and phenylhydrazine hydrochloride yield 1‐phenylazo‐2‐ureido‐carboxy‐cyclohex‐1‐ene (19).
Addition of arylureas to aroyl isothiocyanates and the synthesis of 1‐aroyl‐5‐aryl‐2‐thiobiurets and 2‐aryl‐5‐aroylamino‐2,3‐dihydro‐1,2,4‐thiadiazol‐3‐ones
Authors: Fouli F. A. , Shaban M. E. , Youssef A. S. A. 
Published: December 2004

AbstractThe hitherto unknown 1‐aroyl‐5‐aryl‐2‐thiobiurets (5a–h) were synthesized by addition of mono arylureas (4) to aroyl isothiocyanates (3). Treatment of 1‐aroyl‐5‐aryl‐2‐thiobiurets (5a–h) with alkali gave 5‐aryl‐2‐thiobiurets (6a–e). Oxidation of 1‐aroyl‐5‐aryl‐2‐thiobiurets (5d, f, h) with hydrogen peroxide in the presence of hydrochloric acid or bromine in chloroform gave 2‐aryl‐5‐aroylamino‐2,3‐dihydro‐1,2,4‐thiadiazol‐3‐ones (7a–c).
O.N‐bis(diphenylphosphino) derivatives of chiral trans‐ and cis‐2‐aminocyclohexanols: Synthesis and enantioselective behaviour as ligands in Rh‐based homogeneous hydrogenation catalysts
Authors: Pracejus H. , Pracejus G. , Costisella B. 
Published: December 2004

Abstracttrans‐ and cis‐2‐Methylamino cyclohexanols (MAC) were prepared in enantiomerically pure forms and transformed into O.N‐bis(diphenylphosphino) derivatives (“PONP”). An analogous trans‐1 R; 2 R‐aminocyclohexanol PONP could only be isolated in an impure form, whereas the attempted synthesis of PONP's of diastereoisomeric trans‐2‐(N‐α‐phenylethylamino)‐cyclohexanols failed. Cationic Rh(I)‐chelates of the new PONP's catalyzed the enantioselective hydrogenation of dehydro‐α‐acylamino acids with ≦97% ee. A comparison of the enantiodiscriminating properties of the MAC‐PONP's with structurally related chiral ligands leads to surprising conclusions.
Zur Wechselwirkung von Donoren mit Diethylaluminiumchlorid. IV. 13C‐NMR‐Untersuchungen zum Ausmaß der Komplexbildung
Authors: Schütz H. , Hallpap P. , Hartung H. , Stadermann D. , Heublein G. , Denissov V. M. , Kolzov A. I. 
Published: December 2004

The Interaction of Donors with Diethyl Aluminium Chloride. IV. 13C‐N.M.R.‐Investigations on the Degree of Complex FormationEt2AlCl has some importance for the initiation of cationic polymerizations where its activity can be influenced by the addition of donor compounds. To enlight the elementary processes quantitative 13C‐n.m.r. spectroscopic investigations of the model systems Et2AlCl/pyridine and piperidine, respectively, were carried out. Detailed information are given with regard to the molar ratios of acceptor and donors. The formation of an ionic intermediate complex was observed. The degree of complex formation is higher for piperidine than for pyridine. In the case of pyridine a 1:1 complex is formed. With piperidine a complexation with higher coordination must be assumed.
Studies on the oxidative cleavage of the CC triple bond during the Autoxidation of Acetylenic Hydrocarbons 1. Evidence for α‐dicarbonyl compounds as intermediates
Authors: Rao T. S. S. , Pritzkow W. 
Published: December 2004

AbstractExamination of oxidation mixtures of 1‐phenylprop‐1‐yne, 1‐phenylbut‐1‐yne and 1‐phenyl‐3‐methylbut‐1‐yne revealed the presence of hitherto not reported interesting products, especially the α‐dicarbonyl compounds 1‐phenylpropane‐1,2‐dione, 1‐phenylbutane‐1,2‐dione and 1‐phenyl‐3‐methylbutane‐1,2‐dione respectively in minor quantities. Some other typical products like benzil, benzoic anhydride and phenyl benzoate were also characterized. Although the oxidation of diphenylacetylene is very slow, benzil could be found as the main detectable product along with traces of benzoic acid. The α‐diketones corresponding to the 1‐phenylalk‐1‐ynes were oxidized at 110°C. In each case benzoic acid and the lower carboxylic acids as in the case of the autoxidation of the corresponding acetylenes were obtained. Benzil, benzoic anhydride and phenyl benzoate were also characterized in all the cases. Therefore, α‐diketones are considered as intermediates responsible for the formation of the oxidative cleavage products of the CC triple bond.
Pyryliumverbindungen. 36. Substituierte Benzoesäureester aus 2,4,6‐Triaryl‐pyryliumsalzen und α‐Ketocarbonsäureestern
Authors: Zimmermann Thomas , Fischer Gerhard W. 
Published: December 2004

Pyrylium Compounds. 36. Substituted Benzoic Acid Esters from 2,4,6‐Triarylpyrylium Salts and α‐Ketocarboxylic Acid Esters2,4,6‐Triarylpyrylium salts 1 react with α‐ketocarboxylic acid esters 2 in the presence of two equivalents of an appropriate condensing agent (e.g. dialkylamine salts of weak acids, triethylamine/acetic acid, or sodium acetate) to give 2‐aroyl‐3,5‐diarylbenzoic acid esters 3. However, using only one equivalent of the condensing agent, the formation of 3,5‐diarylbenzoic acid esters 5 predominates. Alkaline saponification of the new esters 3 and 5 yields the corresponding substituted benzoic acids 4 and 6, respectively. – I.r., u.v., n.m.r. and mass spectroscopic data of the novel products 3–6 are reported.
Ketene‐S,N‐acetals as synthons for heterocycles New Synthesis of Pyrimidinones
Authors: Gelbin Michael , Martin Dieter 
Published: December 2004

AbstractKetene‐S,N‐acetals of type 1, 2 reacted with isocyanates to 5‐cyano‐uracils 3 and 5‐cyano‐pyrimidin‐2‐ones 4, 5. Reaction of these with N nucleophiles was investigated furnishing 6‐amino‐pyrimidinones 6 as well as condensed pyrimidin‐2‐ones 7‐‐10 and 13. Cyanic acid esters gave 5‐cyano‐pyrimidin‐4‐ones 16. Behavior of 16 toward nucleophiles is reported.
Reaktion von O,O‐Dimethylthiophosphorsäureamid mit Chloral
Authors: Teichmann H. , Schnell M. 
Published: December 2004

Reaction of O, O‐Dimethyl Phosphoramidothioate with ChloralThe system O,O‐dimethyl phosphoramidothioate (1)/chloral was investigated at room temperature. Two competing reactions occur: (A) formation of the 1:1 adduct 2, and (B) sulfur/oxygen exchange yielding the oxo compound 3, which subsequently forms a chloral adduct 4.
Push‐pull‐Butadiene. VIII. Reaktionen von substituierten Penta‐1,4‐dien‐1,1,5,5‐tetracarbonitrilen
Authors: Peseke K. , Michalik M. , Schönhusen U. , Quincoces J. , Radeglia R. 
Published: December 2004

Push‐pull‐Butadienes. VIII. Reactions of Substituted 1,4‐Pentadiene‐1,1,5,5‐tetracarbonitriles4‐Aryl‐2‐methylthio‐1,4‐pentadiene‐1,1,5,5‐tetracarbonitriles 1 react with bromine to give the nicotinonitriles 2. Compounds 2 and hydrazine hydrate yield the pyrazolo[3,4‐b]‐pyridines 7. Bis(methylthio)nicotinonitriles 9 are prepared by the treating of 2 with methanethiol in an alkaline solution. Compounds 1 can be converted with hydrobromic acid or hydrochloric acid to the nicotinonitriles 2a‐‐c and 2d‐‐f, respectively.
Protonierung und Solvatation schwacher organischer Basen. III. UV‐ und 1H‐NMR‐spektroskopische Untersuchungen zur Basizität von 1,3‐Diketonen
Authors: Kröger C.‐F. , Freiberg W. , Hauer U. 
Published: December 2004

Protonation and Solvation of Weak Organic Bases. III. U.V. and 1H‐N.M.R. Spectroscopic Investigations of the Basicity of 1,3‐DiketonesBy 1H‐n.m.r. spectroscopy it is possible to determine separately the basicity parameters (H0)1/2 or pK and the solvation paramters m, ϕ or m* for the keto and the enol form of acetylacetone. By u.v. spectroscopy only brutto parameters of the equilibrium mixture for acetyl‐ and benzoylacetone as for dibenzoylmethane are available.
Kristallinflüssige trans‐4‐(ω‐Cyanalkyl)cyclohexylester und 4‐(ω‐Cyanalkyl)phenylester
Authors: Deutscher H.‐J. , Krieg R. , Frach R. , Kresse H. , Zaschke H. 
Published: December 2004

Liquid Crystalline trans‐4‐(ω‐Cyanalkyl)cyclohexylester and 4‐(ω‐Cyanalkyl)phenylestersThe synthesis of the title esters 1 and 2a–e (n = 0 – 3) and their mesomorphic properties are described. When the alkyl‐spacer n between the polar CN‐group and the cyclohexane ring of cyanalkyl‐cyclohexylesters 1 is increased the difference of the clearing points between the phenylesters 2 and the cyclohexylesters 1 decreases to nearly zero. The reason of higher clearing temperatures of 2 is a dynamic conformational effect of ring inversion of cyclohexane in the ester 1 with two polar substituents at the ring.
Construction of the Alkyl Side Chain of 11‐Deoxyprostaglandins Using the Aldol Reaction of Substituted Cyclopentane Carbaldehydes with Heptan‐2‐one
Authors: Mahrwald Rainer , Schick Hans , Vasil'eva L. L. , Pivnitsky K. K. 
Published: December 2004

AbstractThe aldol reaction of the substituted cyclopentane carbaldehydes 1 with heptan‐2‐one was demonstrated to offer an effective alternative to the carbonyl olefinations generally used for the build‐up of the (E)‐3‐oxooct‐1‐enyl side chain of 11‐deoxyprostaglandins. In this case dimethyl 2‐oxoheptylphosphonate can be substituted advantageously by the cheaper heptan‐2‐one as side chain precursor.
Kristallin‐flüssige Heterocycloalkane. III. Synthese und kristallin‐flüssiges Verhalten substituierter 1,3‐Dioxadecaline
Authors: Tschierske C. , Zaschke H. 
Published: December 2004

Liquid‐Crystalline Heterocycloalkanes. III. Synthesis and Liquid‐Crystalline Properties of Substituted 1,3‐DioxadecalinesLiquid‐crystalline 2‐substituted and 2,6‐disubstituted 1,3‐dioxadecalines (4—6) were synthesized by acid‐catalyzed acetalization of trans‐2‐hydroxymethylcyclohexanol (1) or trans‐4‐alkyl‐trans‐2‐hydroxymethylcyclohexanoles (2) with aldehydes 3 whereby the desired transisomers were formed only. The syntheses of the various aldehydes are also described.Special attention is drawn on the evolution of mesogenic properties of the titlecompounds 4—6 in comparison with known decalines and 1,3‐dioxanes.It was found that the clearing temperatures of the synthesized 1,3‐dioxadecalines are always lower than those of the corresponding decaline derivatives, due to the deformation of the decalineringsystem by the introduction of two oxygen‐atoms. The comparison of 1,3‐dioxanes and 1,3‐dioxadecalines shows that the dioxadecaline ringsystem tends to suppress smectic mesophases in favour of nematics. A first example of a liquid crystalline cis‐fused 1,3‐dioxadecaline (8) is described, too.
Nitration of the Acetanilide‐type Compounds
Authors: Daszkiewicz Zdzislaw , Kyziol Janusz B. 
Published: December 2004

AbstractSome aromatic compounds containing the imino group (NH) were nitrated in acetic acid or anhydride, and the ortho/para ratios were measured. N‐Methyl derivatives of the aforementioned compounds are much less reactive when nitrated under comparable conditions and give significantly lower o/p ratios. These results along with the literature data support the hypothesis that the acetanilide‐type compounds are nitrated via N‐nitro intermediates.
Nitriles in heterocyclic synthesis: A new approach for the Synthesis of Thiazole derivatives
Authors: Ibrahim N. S. , Mohareb R. M. , Elnagdi M. H. 
Published: December 2004

AbstractThe reaction of 4‐bromo‐3‐oxo‐butyranilide (1) with KSCN afforded the thiocyanato derivative 2. 2‐Dicyanomethylthiazol‐4‐yl‐acetanilide (3) was synthesised by reaction of 2 with malononitrile. A variety of substituted thiazol‐2‐yl malononitriles were prepared by reaction of 3 with hydroxylamine hydrochloride, phenylhydrazine and cinnamonitrile derivatives. The structure assignments of the new compounds are based mainly on 13C and 1H‐n.m.r. spectroscopic data.
Säurestärke und Komplexbildung von Curcuminoiden
Authors: Arrieta A. , Dietze F. , Mann G. , Beyer L. , Hartung J. 
Published: December 2004

Acidity and Complex Formation of CurcuminoidsThe stoichiometric acid dissociation constants of curcumin 1a and derivatives as well as the stoichiometric stability constants of the Cu(II)‐ and Ni(II)‐complexes of these substances have been determined by pH‐potentiometric titrations in dioxane‐water mixture.The influence of different substituents on the pKa‐values and the stability constants is discussed. The complexing properties of the COCH2CO structural element of the ligands are not significantly changed when the phenyl group is substituted by the styryl group. Solid CuL2‐complexes have been characterized. The coordination of the ester group in the tricarbonyl ligand systems 4 was excluded by i.r. spectroscopy.
O‐Methylierung von tert.‐Alkylbrenzcatecholen. Analytische Methode zur Bestimmung der Zusammensetzung von Produktgemischen und Synthese‐variante zur Herstellung von 4‐tert‐Alkylveratrolen
Authors: Beger J. , Meerbote M. 
Published: December 2004

O‐Methylation of tert‐Alkylpyrocatecholes. Analytical Method for Determination of the Content of Product Mixtures and Way for Preparation of 4‐tert‐AlkylveratrolesThe O‐methylation of tert‐alkylpyrocatecholes with dimethylsulfate leads to a mixture of substituted guaiacoles 6/7, 9/10 and veratroles 5, 6 which are separated by gas/liquied‐chromatography for analytical purposes. It is also possible to prepare 4‐tert‐alkylsubstituted veratroles 5 with good yields in this way.On the other hand, the alkylation of veratrole was only successful with lower tert‐alkanols or alkenes. Long‐chained tert‐alkanols fail in this reaction.The analytical and spectroscopical data of some new 4‐tert‐alkylveratroles 5a—g are given.