Eine neue Synthese des Cinnamoyliminodithiokohlensäure-S,S-dimethylesters und Umsetzungen mit Nucleophilen

New Synthesis of Dimethyl-cinnamoylimino-dithiocarboxylate and Reactions with Nucleophiles A new general synthesis of dimethyl-cinnamoylimino-dithiocarboxylate 1d is possible by reaction of 4-nitro-cinnamoylamide with carbon disulfide in the presence of sodium hydride and following alkylation. With the unsubstituted dimethyl-cinnamoylimino-dithiocarboxylate 10 is in-vestigated the reaction behavior with nucleophilic compounds. The treatment of 1c with primary amines, respectively, by mono- and disubstitution of the methylthio groups yields isothiourea 2 or guanidines 3 . Benzocondensed heterocycles are formed by reaction of 1c with o-bifunctional nucleo-philes. The compounds 5, 6 and 7 have been synthesized from 1c with cysteamine, p-phenylenediamine and ethylenediamine. The oxadiazole 8 and isothiosemicarbazide 9 are obtained by reaction of the dithioester 1c with hydrazides. On the other hand cyclisation to the 1,2,4-triazole 11 over the intermediate 10 and to the 1,3,5-triazine 12 are possible. The reaction of 1c with carbanions in a basic medium affords acrylic derivatives 13 . In the same way we isolated by reaction of dithioester 1c with a benzothiazolium salt the dark coloured compound 14 . The physical properties of synthesized compounds are discussed by mass-, ¹H-n.m.r.-, i.r.- and u.v.-spectra.     

Säurekatalysierte Umsetzungen von Aromaten mit Alkanen und Cycloalkanen. IX. Alkylierungen mit 2,2,4-Trimethylpentan (Isooctan)

Acid-catalyzed Reactions of Aromatic Hydrocarbons with Alkanes and Cycloalkanes. IX. Alkylations with 2,2,4-Trimethylpentane (Isooctane) The non-conventional alkylation of benzene, toluene, ethyl- and isopropylbenzene, fluoro- and chlorobenzene with 2,2,4-trimethylpentane in the presence of acid catalysts is described. The composition of the rather complex reaction mixtures is determined by gas-liquid chromatography and mass spectrometry, tert. butylarenes being the main products beside alkylsubstituted indanes and tetralines. Their formation is interpreted as a competition between fragmentation and isomerization of the alkylating agent. By use of trifluoromethanesulfonic acid or combinations of catalysts from HF or HSO₃F with variant metallic fluorides at lower temperatures the selectivity of the reaction may be partially raised.     

Über Umsetzungen von Saccharose mit 1- (n-Alkoxy)-äthylisocyananten

Reaction of Sucrose with 1-(n-Alkoxy)-ethylisocyanates A method for the preparation of some new long chain mono-N-[1-(n-alkoxy)-ethyl]-carbamates of sucrose has been reported. Reaction conditions of this procedure, as well as the properties of sucrose mono-N-[1](n-hexoxy)-ethyl- 1 , mono-N-[1-(n-octoxy)-ethyl]- 2 and mono-N-[1-(n-decoxy)-ethyl]-carbamates 3 (mixture of isomers) were described. The surface tensions of the compounds mentioned have been determinated at various concentrations in water and compared with those of sodium docecylsulphate.     

Umsetzungen des Pentamethylcyclopentadienyl‐Halbsandwichkomplexes Cp*Ta(CO)4 mit Chlor,Brom und Iod

The reaction of Cp*Ta(CO)₄ ( 1 ) (Cp* = η⁵‐pentamethylcyclopentadienyl, η⁵‐C₅Me₅) with chlorine leads to Cp*TaCl₄ ( 2a ), whereas the corresponding reactions with bromine or iodine give the oxo‐bridged complexes [Cp*TaX₃]₂(μ‐O) (X = Br ( 3b ), I ( 3c )). The oxygen atom apparently stems from a carbonyl ligand. In the presence of air, the binuclear complexes 3a , b are converted into mononuclear Cp*Ta(O)X₂ ( 4b , c ). The X‐ray structural determination of [Cp*TaBr₃]₂(μ‐O) ( 3b ) confirms a linear Ta–O–Ta bridge with a Ta–O distance of 190,4(1) pm.     

Synthese von N-sulfinylgeschützten Aminobenzylhalogeniden und Umsetzung mit Nucleophilen

Synthesis of N-Sulfinylprotected Aminobenzylhalides and Reactions with Nucleophiles N-Sulfinylaminotoluenes 3 react with sulfuryl chloride or N-bromosuccinimide to give N-sulfinylaminobenzylchlorides 4 and N-sulfinylaminobenzylbromides 5 , respectively. o-N-Sulfinylaminobenzylchloride 4 a can also be synthesized by the reaction of o-aminobenzylalcohol 6 with thionyl chloride. Nucleophiles react with benzylhalides 4 and 5 to form aminobenzyl ethers, thioethers, and amines 7–9 . Tetrahydrochinazolinethione 11 can be formed by the reaction of 4 a or 5 a with thiocyanate ions followed by the hydrolysis of intermediate 10 .     

Säurekatalysierte Umsetzungen von Aromaten mit Alkanen und Cycloalkanen. X. Alkylierungen mit Cyclohexan

Acid-catalyzed Reactions of Aromatic Hydrocarbons with Alkanes and Cycloalkanes. X. Alkylations with Cyclohexane The complex reaction mixtures of the nonconventional alkylation of benzene with cyclohexane in the presence of Lewis/proton acids and promotors were investigated by gas-liquid chromatography and mass spectrometry. Four representative groups of hydrocarbons were found including cycloalkylbenzenes, substituted indanes or tetralines (C₁₂H₁₆), C₁-C₆-alkylbenzenes and isomeric biscycloalkyls (C₁₂H₂₂). Their formation is interpreted as a competition between alkylation, (without or with isomerization), ringfission with cycloalkylation or fragmentation, and self-alkylation; phenylcycloalkylcations and phenylalkylcations are the intermediates.     

Synthese substituierter 1, 4-Divinylbenzole durch doppelte Heck-Reaktion mit Ethen unter Druck

Substituted 1,4-divinylbenzenes 3a – i were synthesized by twofold Heck coupling from the corresponding 1,4-dibromo) (electron withdrawing substituents) or 1,4-di-iododialkoxybenzenes 1a – i and ethene. Oligomerizations could be suppressed by increasing the pressure of ethene to 30 bar, simultaneously improving the yields of the title compounds.     

Synthese von 2-[Benzazolyl-(2)]-3,3-bis-(alkylthio)-acrylnitrilen und Umsetzungen mit N-Nucleophilen

Synthesis of 2-[Benzazolyl-(2)]-3,3-bis-(alkylthio)-acrylnitriles and Their Reactions with N-Nucleophiles The reactions of benzazolyl-(2)-acetonitriles 1 (1H-benzimidazolyl-, 1-methylbenzimidazolyl-, benzoxazolyl- and benzothiazolyl-) with carbon disulfide in the presence of sodium hydride in dimethylsulfoxide and methylation yield the 2-[benzazolyl-(2)]-3,3-bis-(alkylthio)-acrylonitriles 3 – 5 reacting with amines to the keten-S,N-acetals 6 – 9 . If dinucleophilic reagents are used heterocyclic systems 10 – 14 are formed.     

Konformation und Rotationsbarrieren substituierter Glyoxylsäureamide

Conformation and Rotation Barriers of Substituted Glyoxylic Acid Amides Semiempirical calculations predict an orthogonal orientation of the carbonyl groups in tertiary glyoxylic acid amides, which is in good agreement with an X-ray structure analysis of 5 . Due to the influence of the α-carbonyl group, the rotation barrier in the substituted glyoxylic acid amides 2a–d, 3a, 3b , and 4–6 (ΔG^#_c = 84–92 kJ mol⁻¹) is about 10 kJ/mol higher than in simple acid amides, as was found by dynamic NMR line shape analysis.     

Kristalline und flüssigkristalline copolyester substituierter und unsubstituierter 4-hydroxybenzoesären

Three synthetic strategies were explored to lower the melting point of poly(4-hydroxybenzoate) below 400°C. Binary copolyesters of 4-hydroxybenzoic acid and 3-substituted 4-hydroxybenzoic acid were highly crystalline, regardless of composition, and did not melt below 400°C. In contrast ternary and quartenary copolyesters containing 3-bromo-4-hydroxybenzoic acid may possess melting points below 360°C. Binary copolyesters of 4-mercaptobenzoic acid and 3-substituted 4-hydroxybenzoic acids melt in the range of 360–400°C. Random copolyesters of 3-(4-hydrophenyl) propionic acid and 4-hydroxybenzoic acid are mainly amorphous with glass-transition temperatures between 50 and 15°C. They contain liquid-crystalline domains, which in the case of the 1:1 copolyester are stable over a range of ca. 400°C. The heat-distortion temperatures are low (60–80°C) due to the predominant influence of the amorphous matrix.     

Photochemie substituierter Cycloheptatriene. XVII. 1-Aryl-4-(p-dimethylaminophenyl)-cycloheptatriene

Photochemistry of Substituted Cycloheptatrienes. XVII. 1-Aryl-4-(p-dimethylaminophenyl)-cycloheptatrienes The photochemistry of the title compounds is different from that of the isomeric 1-(p-dimethylaminophenyl)-4-aryl-cycloheptatrienes. The sigmatropic 1, 7-hydrogen shift is dominant caused by the arylic substituent in position 1 of the seven-membered ring. Only strong donor substituents like the p-methoxyphenyl group in position 1 cause photovalence tautomerism. The properties of solvents influence both the quantum yields of the photoreactions and the fluorescence quantum yields. The connections between the fluorescing state and the photoreactivity are discussed. Solvent viscosity and polarity are shown to be relevant for the deactivation parameters.     

1-Amino-4-aryl-2(1H)-pyrimidinthione: Acidität und Komplexbildung mit Mn(II), Co(II), Ni(II), Zn(II), Cd(II), Pb(II) und Ag(I)

1-Amino-4-aryl-2(1H)-pyrimidinethiones: Acidity and Complex Formation with Nonferrous Metal Ions and Ag(I) Acid dissociation constants of new 2, 3 and already known 1 substituted 1-amino-4-aryl-2(1H)-pyrimidinethiones and stability constants of their nonferrous metal ion and silver complexes have been measured pH-potentiometrically in a 75% (v/v) mixture of dioxane/water. The influence of the substituents on pK_a- and lgβ_n-values is discussed. The X-ray structure analysis of bis[1-(4-toluenesulfonamido)-4-(4-tolyl)-2(1H)-pyrimidinethionatol]-nickel(II) 5 proves that pyrimidinethiones coordinate via their thione sulphur and aminonitrogen. However, the bond lengths are not levelled in the chelating ring.     

Photochemie substituierter Cycloheptatriene. XII. Dualfluoreszenz von 1-Aryl-4-(p-dimethylaminophenyl)-cycloheptatrienen

Photochemistry of Substituted Cycloheptatrienes. XII. Dual Fluorescence of 1-Aryl-4-(p-dimethylaminophenyl)-cycloheptatrienes Diarylcycloheptatrienes 1 in solution show two fluorescences originating from two different excited states. The ratio of intensities of the two fluorescences depends on the excitation energy. Two alternatives are discussed as the origin of the dual fluorescence: conformers in the ground state or an adiabatic photoreaction, respectively. The two emissions are ascribed to different geometries of the seven-membered ring. Despite the different excitation spectra the dual fluorescence of the compounds 1 is explained as an excited state property of a single absorbing species, and not as two ground state species giving rise to the two fluorescence bands.     

Synthese substituierter 2-Aminochinolin-1-oxide durch reduktive Cyclisierung substituierter 3-(2-Nitrophenyl)acrylnitrile

Synthesis of Substituted 2-Aminoquinoline-1-oxides by Reductive Cyclization of Substituted 3-(2-Nitrophenyl)acrylonitriles An approach to the class of 2-aminoquinoline-1-oxides is given based on reductive cyclization of appropriate substituted 3-(2-nitrophenyl)acrylonitriles. Thus, 2-nitrobenzylidene compounds 1 a – d have been reductively cyclized by H₂/PtO₂ or H₂/Pd-C under normal conditions to form N-oxides 2 a – d . ¹H-NMR data show that 1 d has to be regarded as ethyl(Z)-2-cyano-3-hydroxy-3(2-nitrophenyl)acrylate. The analogous (2-nitrobenzoyl)acetonitrile 3 , however, did not cyclize under the same conditions, but yielded anthraniloylacetonitrile 4 . The results are discussed in comparison with the reaction behaviour of structural related nitronitriles under comparable conditions. A short survey of reactions leading to heterocyclic N-oxides by reductive cyclization of nitro compounds is given.