Zur Reaktion von Cyanodithioformiaten mit primären Aminen

Reactions of Cyanodithioformates with Primary Amines N-Alkyldithiooxamides 3 and N,N -dialkyldithiooxamides 4 were synthesized in good yields by reaction of cyanodithioformates 1 with primary aliphatic amines. N-Alkylcyanothioformamides 2 , intermediates in these reactions were obtained in very low yields only. The reaction of 1 and diaminoethane or 1.3-diaminopropane afforded imidazolidine-2-thione 5a respectively perhydropyrimidine-2-thione 5b . The reaction of 1 with 1-chloro-2-aminoethane did gave 2-thiocarbamoylthiazoline 7 .     

Tetrathiafulvalene. XXVIII. Diastereoselektive Bildung unsymmetrisch substituierter Tetrathiafulvalene

Tetrathiafulvalenes. XXVIII. Diastereoselective Formation of Unsymmetrically Substituted Tetrathiafulvalenes As a part of our work on chemistry of tetrathiafulvalenes, we make a contribution to elucidate the mechanism of forming tetrathiafulvalenes starting from 1,3-dithiole derivatives. We describe the synthesis of unsymmetrically substituted tetrathiafulvalenes ( 8a–i ) starting with the 2H-1,3-dithiolium salt ( 7a–i )/tert. amine, 2-ethylthio-1,3-dithiolium salt ( 5a–i )/triphenylphosphine or 1,3-dithiole-2-thione ( 4a–i )/triethyl phosphite. If the 1,3-dithiole derivatives are substituted by bulky groups the isolation of the cis- and trans-isomers was possible due to differences in the solubility. In these cases ( 8c–i ) the predominant formation of the cis-isomer is observed in the reaction of 2-ethylthio-1,3-dithiolium salts ( 5c–i ) with triphenylphosphine or 1,3-dithiole-2-thiones ( 4c–i ) with triethyl phosphite. This result is in agreement with the formation of an intermediate, analogously to the Wittig reaction. In the reaction of 2H-1,3-dithiolium salts ( 7a–i ) with tertiary amines the relation of isolated cis- and trans-isomers is not 1:1 and depends on the bulkiness of the tertiary amine. These observations exclude in these three reactions a carbene mechanism for the dimerization of the 1,3-dithiole units to tetrathiafulvalenes.     

Untersuchungen zur reaktion von o-kresol mit formaldehyd unter verwendung tertiärer amine

The reaction between o-cresol and formaldehyde was investigated using various tertiary amines as catalysts. The influence of the reaction parameters basicity, temperature, reaction time and concentration of formaldehyde was discussed. To yield preferentially 2,4-bis(hydroxymethyl)-6-methylphenol the conditions of synthesis were optimized. The formation of bi- and polynuclear products cannot be avoided.     

Gesetzmäßigkeiten der Polykondensation von Dicarbonsäurechloriden mit Bisphenolen

The paper presents the essential rules underlaying the polycondensation of the title components in organic solvents in the presence of tertiary amines on heating or at comparatively low temperatures. With hydrogen chloride resulting as a low molecular reaction product the condensation proceeds under non-equilibrium conditions. Conducting the condensation at higher temperatures, however, may be accompanied by destructive exchange reactions of the polymer with the starting material or between the polymer molecules themselves, affecting the molecular weight of the polymers obtained. Investigations of the kinetics of polycondensation of terephthalic acid with 9,9-bis-(4-hydrophenyl)-fluorene and 4,4′-(hexahydro-4,7-methyleneindan-5-ylidine)-diphenol at 150 to 200°C in a solvent with high boiling point showed the polyesterification to proceed by an anionic mechanism with formation of acylium ions at the start of and during the reaction. The polycondensation of dicarboxylic acid chlorides with bisphenols was found to depend largely on the components and composition of the initial mixture, temperature and other factors involved. Particularly, the kind of medium chosen for the polycondensation process reflects in the supramolekular structure and, thereby, in the physical properties of the polymer obtained. The results of experiments carried out to clarify the importance of tertiary amines in the polyesterification reaction in solvents at low temperature suggest two catalytic mechanisms, a nucleophilic and a general basic one.     

Anionische lösungspolymerisation von glycolid

The anionic solution polymerization of glycolid yielding polyglycolic acid was examined with several solvent-initiator-systems. The polymerization behaviour in toluene using the tertiary amines triethylamine and N,N-dimethylbenzylamine as initiators and in sulfolan (tetrahydrothiophenedioxide) with N,N-dimethylbenzylamine is described in dependence on initiator concentration and reaction time.     

Thiatriazole. V. Zur Reaktion von Isothiocyanaten mit 1,2,3,4-Thiatriazolderivaten

Thiatriazoles V. On the Reaction of Isothiocyanates with Thiatriazole Derivatives The reaction of 1,2,3,4-thiatriazoles with alkyl and aryl isothiocyanate proceeded differently. Methylisothiocyanate furnished a 2:1 product with 5-amino-1,2,3,4-thiatriazole. Arylisothiocyanates reacted under the same conditions to the known thiapentalenes 6 . 5-Alkyl- and 5-arylamino-1,2,3,4-thiatriazoles gave 5-substituted 1,2,4-thiadiazol-3-thions 8 . Similar the hydrazones of 1,2,3,4-thiatriazole reacted with isothiocyanate to form the hydrazones of 1,2,4-thiadiazole-3-thione 10 . 4-Dimethylamino-pyridine is a necessary catalyst for the selectivity of these reactions.     

Zur Aminolyse von Bis-Imidoylchloriden der Oxalsäure. I. Umsetzung mit aromatischen und aliphatischen Aminen

On the Aminolysis of Bis-Imidoylchlorides of Oxalic Acid. Part I. Reaction with Aromatic and Aliphatic Amines The reaction between bis-imidoylchlorides 2 derived from oxalic acid and several aromatic and aliphatic amines was investigated. While primary aromatic amines need a thermical activation by refluxing, primary aliphatic amines give mainly at room temperature the amidines 3 in moderatly up to good yields. Proceeding from enantiomeric pure amines e.g. ( R )- or (S)-1-phenethylamine the new homochiral oxalic amidines 3y and 3z with C₂-symmetry were obtained. Several secondary amines react with the bis-imidoylchloride 2a to give via intramolecular cycloacylation derivatives of isatine. The new synthesized amidines 3 perform systems with a strong molecular dynamic like prototropie and E/Z-interconversion. All new compounds described were characterized by elemental analysis and spectroscopic methods.     

Adhesives from epichlorohydrin elastomers III. Tertiary amine crosslinked adhesives from epichlorohydrin-ethylene oxide copolymer for bonding metals

The mechanical and dielectric properties of epichlorohydrin-ethylene oxide copolymer (EEOC) reaction products with various tertiary amines were investigated. It was found that vulcanizates could be obtained using both monofunctional and difunctional amines. Basing on the results of dielectric loss tangent, volume resistivity and mechanical damping measurements, the presence of ionic crosslinks in tertiary amine-EEOC reaction products was suggested. The adhesives were formulated based on these materials and the tensile and lap-shear strength of A1–A1 bonds were measured. It was found that tertiary amines, especially triethylenediamine, were better crosslinking agents for adhesives than commonly used 2-mercaptoimidazoline and the particular adhesive composition was selected basing on these results.     

Reaktionen von Malonsäureethylesteraniliden mit Heterokumulenen

Reactions of Malonanilic Acid Ethyl Esters with Heterocumulenes Malonanilic acid ethyl esters 1 react with carbon disulfide in the presence of sodium hydride to give disodium salts 2 . Treatment of 2 with an alkylation reagent yields the openchain or cyclic ketene S,S-acetals 3 and 4 , respectively. Adding only one equivalent of methyl iodide to 2 and acidifying the reaction mixture lead to the dithioesters 5 . Reaction of 3 with amines or o-amino-thiophenol yields S,N- and N,N-acetals only in some cases. S,N-acetals 6 are further available by addition of phenyl isothiocyanate to 1 whereas N,N-acetals are synthesized, too, by chlorination of 3 and reaction with amines. Acidifying of 11 gives the thioacetoanilides 12 . Some more reactions (oxidation of 3a , d and saponification/decarboxylation of 4a ) are discussed.     

Darstellung und Reaktionen von 2-Mercapto-6-thioxo-thiopyran-3-carbonsäure-Derivaten

Synthesis and Reactions of 2-Mercapto-6-thioxo-thiopyran-3-carboxylate derivatives 6-Amino-thiopyran-2-thiones ( 1 ) react with dihydrogen sulfide in the presence of pyridine and triethyl amine to yield 6-thioxo-thiopyran-2-thiolates ( 2 ). Methylation of 2 gives the methylthio compounds 3 and 4 . Further methylation of 3a and 4a yields the thiapyrylium salt ( 7 ). The reaction of 2-imino-thiopyran ( 6 ) with carbon disulfide represents another route to the 6-methylthio-thiopyran-2-thione ( 4a ). The 2-methylthio-thiopyran-6-thione ( 3a ) undergoes substitution of the methylthio group with amines to 8 or reacts with phenylhydrazine to phenylhydrazono-thiopyrane ( 9c ). 6-Thioxo-thiophen-2-thiolates ( 2a , b ) react with hydrazine hydrate to give hydrazono-thiopyranes ( 10a , b ) which can be S-methylated. On the contrary 2c gives with hydrazine hydrate under ring transformation the pyridine-2-thiolate ( 11 ). N,S-Acetals ( 12 ) and 1,3,4-thiadiazoles ( 15 ), which give rise to new pyridine derivatives ( 14 ) and ( 17 ), can be obtained from 1-Amino-pyridin-2-thiolate ( 11 ).     

Zur Reaktion von Dicyclopentadiendiepoxid mit Acrylsäure

On the Reaction of Dicyclopentadiene Diepoxide with Acrylic Acid The esterification of dicyclopentadiene diepoxide as a bifunctional epoxide with acrylic acid was investigated. The influence of solvent polarity, reaction temperature and the catalytic system used are discussed. It was found, that the reaction rate increased with increasing solvent polarity. By using tertiary amines as catalysts, only a small catalytic effect was observed. On the contrary, a good catalytic effect was achieved with Lewis-acids. By means of FeCl₃, a vinylester containing epoxide groups and CC-double-bonds is obtained, which polymerizes via various mechanisms.     

Quaternierung von tertiären Aminsalzen mit langkettigen Epoxiden

Quaternation of Tertiary Amine Salts with Long Chain Epoxides The new process for the production of quarternary ammonium compounds operates without pressure at relatively low temperatures with phase transfer catalysts in aqueous dispersion and offers the special advantage of variability with respect to reaction partners, i. e. epoxides, tertiary amines and acids. Polyfunctional compounds can also be used. They yield final products having several quarternary centres or polymeric quarternary salts. These substances are interesting in the area of cosmetics, desinfectants and textile treatment.     

Durch bisquartäre Ammoniumsalze katalysierte Zweiphasenreaktion von 1-Bromoctan mit Natriumacetat und Kaliumacetat

Two-Phase Reaction of 1-Bromooctane with Sodium Acetate and Potassium Acetate Catalyzed by Diquaternary Ammonium Salts New unsaturated diquaternary ammonium salts (diquats) were prepared in two ways from ditertiary amines 3 and 1-bromoalkanes or from 1, 4-dibromobut-2t-ene and tertiary monoamines. A comparison of their catalytic ability with that of saturated diquats and with that of corresponding monoquats was made. The reaction of n-C₈H₁₇Br with NaOAc or KOAc in the two-phase system liquid-liquid without an additional solvent is catalyzed more effectively by the unsaturated diquats than by the saturated diquats and the monoquats. Most of the used quats catalyze the ester formation from NaOAc more effectively in the system liquid-liquid, however, the ester formation from KOAc more effectively in the system solid-liquid; KOAc is generally superior to NaOAc in both systems. Consequently, in the phase-transfer catalyzed ester formation from alkali acetate and alkyl halides not only the structure of the quat but also the inorganic cation of the acetate have influence on the rate of conversion.     

An experimental and theoretical study on the effects of amine chain length on CO2 absorption performance

To explore the effect of amine chain length on CO₂ absorption performance, the reaction kinetics of CO₂ absorption in aqueous 1-dimethylamino-2-propanol (DMA2P), 1-diethylamino-2-propanol (DEA2P), 2-(methylamino)ethanol (MAE), and 2-(ethylamino)ethanol (EAE) solutions with different concentrations were explored using the stopped-flow apparatus. Additionally, Density Functional Theory (DFT) calculations were conducted to examine the reaction mechanism and the free energy barrier of the elementary reactions underlying CO₂ absorption in these four aqueous amine solutions. Kinetic models for CO₂ absorption in tertiary amines and secondary amines were established, based on the base-catalyzed hydration mechanism and the zwitterion mechanism, respectively, both of which perform well in predicting the relationship between k₀ and the amine concentration. The free energy barrier obtained by DFT is consistent with the activation energy barrier trend obtained by experiment. In addition, the effect of chain length on the free energy barrier was investigated through the chemical bond and weak interaction analysis.     

Anlagerungsprodukte von Epichlorhydrin an langkettige Amine

Products Formed by the Addition of Epichlorohydrin to Long Chain Amines Long chain amines and ammonium compounds having reactive chlorohydrin and epoxy groups respectively were of interest as potential reactive softeners for textiles. Methods for the preparation of such compounds have been sought in extensive studies. The author describes the reaction of secondary and tertiary long chain amines with epichlorohydrin and glycerindichlorohydrin respectively, and deals with the structure of the resulting products. The mechanism of formation of certain classes of compounds, which were obtained unexpectedly, is discussed.     

Homogeneous Catalytic Cleavage of Saturated Carbon-Nitrogen Bonds

An evaluation of the catalytic reactivity of [CPD (CO)₂RuH]₂ (1) and (CPD)(CO)₃Ru (2) (where CPD = tetraphenylcyclopentadienone) with amines suggests that these complexes catalyze C-N bond cleavage by activating C-H bonds alpha to the nitrogen atom of tertiary, secondary and primary amines at ca. 140° C. When two different amines are used, transalkylation takes place. With secondary and primary amines, ammonia and tertiary amines are formed. A series of amine complexes (CPD)(CO)₂Ru.NR₃ (R = alkyl/H) was isolated from stoichiometric reactions of 1 or 2 with primary and secondary amines. It was found that tertiary amines do not generate complexes of the above type but rather unexpectedly give secondary amine complexes by cleavage of an alkyl group. The only isolatable tertiary amine complex is the moderately stable (CPD)(CO)₂RuNMe₃. All amine complexes were characterized by spectral and elemental analyses. Catalytic aspects of C-N bond cleavage were studied. Complexes (1) and (2) were found to react with primary, secondary and tertiary amines to generate imminium or eneamine species which subsequently undergo hydrolysis with water. This is in contrast to the Ru carbene mechanism previously proposed for cluster catalyzed C-N bond activation and cleavage. The two reactions are compared with respect to D for H exchange (with D₂O), water requirement and production of trace products during catalysis. A primary alcohol was found to substitute alkyl groups of a tertiary amine under the catalytic action of 1. A catalytic reaction cycle is proposed.     

Dienoligomerisierung. XV. Palladiumkomplexkatalysierte Telomerisierung von Butadien mit Aminen und Dimerisierung in Gegenwart von Ketoximen

Diene Oligomerization. XV. Palladiumcomplexcatalyzed Telomerization of Butadiene with Amines and Dimerization in the Presence of Ketoximes Butadiene reacts with primary or secondary amines and with the homogeneous catalytic system bis-acetylacetonatopalladium-(II)/triphenylphosphine to form 1-amino-octa-2,7-dienes. The rate and the selectivity of the reaction increase in presence of cocatalysts as triarylphosphates instead of triphenylphosphine and if the reaction proceeds in a protic media — in alcohols, water or lower carboxylic acids. A number of 1-aminoocta-2,7-dienes were prepared. If oximes act as organic nitrogen compounds, only n-octa-1,3,7-triene is selectively formed. Schiff' bases aldolisate under the conditions of the reaction.     

Zur Chemie der Acylthioharnstoffe. III. Bildung von 1,3,5-Thiadiazin-2-thionen bei Acylsenföl-Amin-Umsetzungen

On the Chemistry of Acylthioureas. III. Synthesis of 1,3,5-Thiadiazine-2-thiones by the Reaction of Acylisothiocyanates with Amines In course of synthesis of benzoyl-thioureas from benzoyl-isothiocyanate and sec. amines some new 6-amino-4-phenyl-1,3,5-thiadiazine-2-thione 5 are prepared and characterized chemically and spectroscopically.     

Zur Dehydratisierung von Harnstoffen mit Dichlorcarben im Phasentransfer-Verfahren,ein Zugang zu substituierten Cyanamiden

The Dehydration of Ureas by Two-Phase Dichlorocarbene Reaction, a Synthetic Access to Substituted Cyanamides A wide variety of N,N-disubstituted ureas are dehydrated in the CHCl₃/NaOH catalytic two-phase system under mild conditions. The sequence of urea-transamidation and dehydration thus offers a profitable approach to aprotic cyanamides. Among various tested PT-catalysts tertiary amines prove to be the most efficient and favourable ones. Tertiary amines may also be used advantageously in the transformation of carboxylic amides and thioamides to the corresponding nitriles. The application of the same technique is less suitable in the case of N-mono-substituted ureas, N,N′- disubstituted ureas as well as N(dialkylaminomethylidene) ureas, because consequent reactions of the primarily formed cyanamides predominate. Problems concerning the dehydration mechanism are elucidated in terms of HMO-perturbation theory     

Photooxidation von Arylazonaphtholen mit Singulett-Sauerstoff

Photooxidation of Arylazo-Naphtholes with Singlet Oxygen The reaction of p-substituted 4-arylazo-1-naphtholes 1 and 1-arylazo-2-naptholes 5 with singlet oxygen (produced by methylene blue-sensitized photolysis) has been studied spectroscopically in methanol as a solvent. The rate constants of dye bleaching are the same, irrespective whether the extinctions of the azo or the hydrazone forms of the tautomeric systems are measured. Both reaction series 1 and 5 afford linear Hammett plots, which is discussed in the light of the azohydrazone equilibrium of the dyes and an „ene”︁ mechanism of the reaction with singlet oxygen. It could be shown by short-time spectroscopy that the azo-hydrazone isomerization proceeds much faster than the attack of singlet oxygen on the hydrazone form, which explains all observed facts.