Darstellung und Eigenschaften von Ti-substituierten N-Heterocyclen

Preparation and Properties of Ti-substituted N-Heterocycles The compounds (x = 2 to 6) have been prepared by transamination of Ti(NMe₂)₄ with the heterocyclic amines and have been characterised by elemental analyses and ¹H NMR and IR spectroscopy. The dependence on both x and n of the thermal decomposition has been studied for the series and . The results can be interpreted in terms of the steric strain of the R₂N and substituents. Apart from the piperidido groups none of the ligands exhibit protective group properties comparable to the R₂N groups.     

Kinetics,mechanism, and endo selectivity of Diels–Alder reactions of alkylmonosubstituted ethenes with cyclohexa-1,3-diene in the gas phase

The reactions where Y = CH₃ (M), C₂H₅ (E), i? C₃H₇ (I), and t? C₄H₉ (T) have been studied between 488 and 606 K. The pressures of CHD ranged from 16 to 124 torr and those of YE from 57 to 625 torr. These reactions are homogeneous and first order with respect to each reagent. The rate constants (in L/mol·s) are given by The Arrhenius parameters are used as a test for a biradical mechanism and to discuss the endo selectivity of the reactions.     

Effect of gegen ion in cationic polymerization and copolymerization of trioxane

p-Chlorophenyldiazonium hexafluorophosphate has been reported to be a superior catalyst for cationic polymerization and copolymerization of trioxane as compared to boron trifluoride dibutyl etherate (BF₃·Bu₂O)¹. In the present investigation the effect of anions derived from elements in Group VA, AsF and SbF, has been ascertained. It has been concluded that p-chlorophenyldiazonium hexafluoroarsenate is also a superior catalyst to boron trifluoride dibutyletherate (BF₃·Bu₂O), while p-chlorophenyl-diazonium hexafluoroantimonate is inferior. Copolymers with the highest polymer yield (>95%) and molecular weight (intrinsic viscosity = 4 to 5) were obtained with Simple dependences on catalyst concentration have been observed to hold for a wide catalyst concentration range ([M]/[C]) = (1 to 20) × 10⁵: For the same relationships hold. However, the polymer yield (75%) and molecular weights (intrinsic viscosity ?1) are considerably lower while the extent of chain transfer is higher. Furthermore, the polymerization proceeds with explosive violence. The quantitative aspects resulting from polymerization, for the most part, can be interpreted in terms of the extent of dissociation of the propagating ions.     

Structure of the tetramer of α-methylstyrene

The structure of the tetrameric dianion formed by α-methylstyrene in tetrahydrofuran by reaction with sodium has been examined. Mass spectral, NMR, infrared, and kinetic data all indicate that the structure is rather than the structure which had previously been assumed for this species.     

Durch Nachbargruppenbeteiligung induzierte (1,2)-Chlorwasserstoff-Eliminierung aus ionisiertem 2-(β-Chloräthyl)- benzoesäuremethylester

By using deuterium labelled compounds and collisional activation spectra the mechanism of the unusually intensive HCl elimination from 2-(β-chloroalkyl)benzoic acid methyl ester as well as the structure of the product ion have been elucidated. It can be shown that the structure of the stable ion (lifetime τ～10?5 s) is best represented by 2-vinyl benzoic acid methyl ester whereas the reactive ion (lifetime τ<10^?6 s) at least partially rearranges to a cyclic ion. The hydrogen chloride elimination from 2-(β-chloroalkyl)benzoic acid is apparently a simple 1,2 process. A closer examination reveals that the reaction represents a further example of an unusual neighbouring group participation of the ester function.     

Living cationic polymerization of 2-chloroethyl vinyl ether: Kinetics,mechanism and application to polymer synthesis

The cationic polymerization of 2-chloroethyl vinyl ether initiated by HI/weak Lewis acid (I₂ or ZnI₂) systems has been studied from both a kinetic-mechanistic and a synthetic viewpoint. At low temperature and in toluene as solvent, the polymerization proceeds via a living process and the kinetic order with respect to monomer varies according to the nature of the Lewis acid activator. This behaviour can be explained by the coordination of the Lewis acid with both the monomer and the chain-end, the latter leading to a strong activation of the -I bond towards monomer insertion. The living polymerization obtained from divinylether precursors leads to -I ended telechelics, and their transformation into dihydroxytelechelic oligomers has been performed. The chemical modification of chloroalkyl side groups by phase transfer catalysis allows the attachment of specific groups without consumption of-OH ends.     

Modification of poly(vinyl alcohol) through reaction with phosphorus-containing reactants

Crosslinked products of the form: and have been formed from the interfacial condensation of phosphorus diacid halides with poly(vinyl alcohol). Product yield and amounts of phosphorus reactant included in the product increases as the amount of base increases. Product stability in aqueous systems decreases in the order neutral > base > acid.     

The mass spectra of some chlorinated aromatic pesticidal compounds

Mass spectral studies of some chlorinated aromatic pesticidal compounds are reported. The compounds studied include substituted diphenyl derivatives of methane, ethene and methanol. The diphenylmethanes are characterized by a relatively intense peak at m/e 165. Comparison of their low voltage spectra with 9-dichloromethylfluorene indicates that this ion has a fluorenyl ion structure. The structure of the base peak (m/e 246) of the diphenylethenes was investigated by comparing competitive metastable transitions with 9-dichloromethylenefluorene and utilizing defocusing metastables. Additional studies of model compounds suggest that the m/e 246 ion is very complex and is probably comprised of a number of structures. The mass spectra of the diphenylmethanols are significantly different from the other two groups. The hydroxyl group markedly affects the fragmentation process for these compounds; the characteristic peak is presumably the chlorobenzoyl ion and is probably precursor for other fragment ions. Mass spectral correlations of pesticidal compounds of similar structure are needed to obtain enough background to facilitate interpretation of the mass spectra of their metabolites. Furthermore, such studies make feasible the identification of characteristic product ions formed by rearrangement processes during ionization of organic molecules in the gas phase. This information can be a nucleus for correlating the other significant mass spectral data of an unknown compound. Intensive studies of carbamates,¹ organophosphorus² and bridged polycyclic chlorinated pesticidal³ compounds were invaluable in identifying metabolites of the aforementioned pesticides.^4,5,6 The compounds in this Work are chlorinated aromatic pesticidal compounds which consist of a diphenylemthane, a diphenylethylene, or a diphenylmethanol structure. The compounds p,?-DDE were briefly discussed by Jorg, Houriet and Spiteller.⁷ The compounds examined are listed in Table 1. Treatment of data. The mass spectra of the pesticides are presented as bar graphs in Figs 1 to 12 It a metastable peak is observed, the metastable transition is indicated by m^* on the figures and also by (m^*) when confirmed or identified using the defocusing technique.⁸ Since the relative abundances of the metastable peaks for these compounds are very small (<0.1%) on special effort was made to establish their presence unless they wre pertinent.     

Kinetics of recombination,dismutation, and disproportionation reactions involving neutral ketyl radicals and radical anions

The kinetics of fast elementary recombination of neutral ketyl radicals of benzophenone and its four derivatives (BPH?), the dismutation of benzophenone radical anions, the disproportionation between BPH? and stable nitroxyl radicals, ( ), and the electron transfer have been investigated in both individual solvents and binary mixtures of different viscosities. Reaction (1) for unsubstituted BPH in water, water glycerol, and n-hexane is controlled by diffusion with 2k₁ ? k_diff. In aliphatic alcohols and toluene, which form solvation complexes with BPH?, reaction (1) is diffusion-enhanced and activation-controlled, respectively, with 2k₁ < k_diff. In a viscous solvent such as 1-propanol–glycerol mixture (100 ? η ? 450 cP) reaction (1) is diffusion-controlled. Reaction (2) in alkaline 1-propanol and alkaline 1-propanol–glycerol mixture is activation controlled. The rates of reactions (3) and (4) for benzophenone radicals and nitroxyl radicals of the imidazoline series decrease as the viscosity of the water–glycerol and 1-propanol–glycerol mixtures is increased. The reactions are molecular mobility limited; nevertheless, the numerical values of k₃ (k₄) are 2–6 times as small as the corresponding k_diff values due to the low steric factor of the reactions (therefore called pseudodiffusion-controlled reactions). The theoretical estimates of k₃ (k₄) are in good agreement with the experimental results. The elimination of spin forbiddance in the process of radical recombination in viscous solvents is discussed.     

The loss of CH3⋅ from some unsaturated dithioesters

The mechanism for the loss of CH₃? (and C₂H₅?) from the molecular ions of some unsaturated dithioesters of the type with n=0, 1, 2, has been studied. Based on first field free region metastable ion characteristics it is proposed that 1,3-dithiolium type product ions are generated. Deuterium labelling experiments indicated that the molecular ions of the 2-alkenyl alkanedithioates undergo a rearrangement prior to fragmentation which resembles the [3,3]sigmatropic rearrangement in solution chemistry.     

Étude des Paramètres de Résonance Magnétique Nucléaire et de la Stéréochimie de Thiono-2 R-2 Dithiaphosphorinanes-1,3,2

The ¹H, ¹³C and ³¹P n.m.r. spectra of eleven 2-R-2-thiono-1,3,2-dithiaphosphorinanes with various R groups attached to the phosphorus atom have been recorded and analysed. In the compounds where R=Cl, OMe or N, the molecule adopts a chair conformation with the R group axially oriented. When the molecule adopts a chair conformation with equatorially oriented R. In the case of the derivatives with R=phenyl, Me, N(Me)₂ or NHt-Bu, a chair–chair conformational equilibrium was observed. The hindered rotation about the P? N bond was also examined in the derivative with      

Thermal decomposition of 3-chloro-3-trichloromethyldiazirine in solution

The thermal decomposition of 3-chloro-3-trichloromethyldizairine in carbon tetrachloride and iso-octane has been investigated over the temperature range 75–115°C. The products, tetrachloroethylene and nitrogen, are formed quantitatively by a first-order reaction which is probably unimolecular: The results yielded the following Arrhenius equations: .     

Synthesis and psychotropic properties of furyl- and thienyl-germatranes

Trihalogermyl-furans and -thiophenes were prepared by inserting germanium dibromide (GeBr₂) generated from the dibromogermane(II) dioxanate complex into the carbon-halogen bond of halo-furans and -thiophenes. Their ethanolysis and transesterification by triethanolamine yielded the germatranes which were subjected to psychotropic activity assays. The psychotropic properties of germatranes were found to depend on the type of the heterocycle and on the position of the germatrane moiety.     

Competition entre les réactivités dipolarophiles et nucléophiles des pyrazolines-2 dans l'action de l'oxyde de benzonitrile. Synthèse,identification, comportement chimique des tétrahydropyrazolo-[4,5-b] oxadiazoles-1,2,4

The reaction of benzonitrile oxide with different series of Δ²-pyrazolines provides evidence for the three reactive centers of compounds i.e., the dipolarophile reactivity of the C = N-bond, and the presence of the two the other nucleophilic sites: the N₁ nitrogen atom and the C₃ carbon atom for unsubstituted pyrazolines at these corresponding positions. Furthermore the regiospecificity of the cycloaddition reaction leading to new series of condensed heterocycles is well demonstrated.     

Metastable decompositions of cyclopentanol ions and [C5H10O]+˙ ions with the oxygen on the first carbon

Ionized cyclopentanol and [C₅H₁₀O]+˙ ions with the oxygen on the first carbon lose methyl, ethylene, ethyl, ethane and water in their metastable decompositions. We show by collisionally activated decompositions of the products that the losses of ethyl form CH₃CH₂C?O⁺, the losses of ethylene form , and the losses of methyl probably yield . Deuterium labeling indicates that ethyl loss from ionized cyclopentanol occurs following α-cleavage of the ring, isomerization to the enol isomer of ionized n-pentanal and subsequent isomerization to the 3-pentanone ion.     

Thermal decomposition of 1,1,2,2-tetramethylcyclopropane in a single-pulse shock tube

1,1,2,2-Tetramethylcyclopropane (TTMC) has been decomposed in a single-pulse shock tube. The main reaction process is Side reactions are unimportant. From comparative rate experiments (with cyclohexene decomposition as standard) the rate expression for these reactions are These numbers are consistent with a «best» value for cyclohexene decomposition of      

Bridged polyaromatics: Synthesis,structure, and isomorphous properties of methyl-substituted polymers containing CH2, O,and S bridges

Linear, crystalline polymers corresponding to the general formulas where X is CH₂, O, or S, were synthesized, and their isomorphous relationships were studied. The results point out that a close structural relationship exists within each series of compounds investigated.     

Ab-initioMRD–CI calculations on a C?NO2 decomposition pathway of nitrobenzene

To study molecular decomposition pathways it is necessary to use ab initio multireference determinant–configuration interaction or MCSCF (multiconfiguration SCF ) calculations. The MRD –CI (multireference double excitation–configuration interaction technique of Buenker and Peyerimhoff) calculations on the decomposition pathway of nitrobenzene were carried out using all of the occupied molecular orbitals in the region of the bond being dissociated, plus all of the virtual orbitals. An effective CI Hamiltonian was used into which were folded the effects of all of the occupied molecular orbitals from which excitations were not allowed. So far we have investigated the lowest ¹A₁, ³A₁, ¹A₂, ³A₂, ¹B₁, ³B₁, ¹B₂, ³B₂ states and are investigating the higher states. Our results show a wealth of structure in the potential energy surfaces for the various electronic states of nitrobenzene as a function of distance. A number of the states are predissociative and change dominant configuration one or more times along these potential energy surfaces.     

Synthese und Eigenschaften der 1,3-Benzazaphosphole

Synthesis and Properties of the 1,3-Benzazaphospholes 1H-1,3-Benzazaphospholes (R = H, CH₃, C₆H₅, N(CH₃)₂) are synthesized not only rom o-aminophenylphosphines and different cyclisation compounds such as R? C(OR)?NH · HCl, R? C(O)Cl, R? COOR′, R? C(OCH₃)₂NR′₂, or Cl₂C?N(CH₃)₂Cl but also from secondary o-aminophenylphosphines PRH? C₆H₄? NH₂ (R = C₆H₅, C₂H₅) and CH₃? C(OR)?NH · HCl under elimination of ether or from 1,3-benzazaphospholines after oxidation or thermal treatment. Whereas the 1,3-benzazaphospholes don't react with acetyl chloride or methyl iodide the N-acetyl- and P-methyl-1,3-benzazaphospholes are formed starting with the ambident anion. Further reactions of the 1,3-benzazaphospholes and the nmr data of the compounds prepared are discussed.      

Metal Complexes of 4,7-Dithiadecane-1,10-dicarboxylic Acid and Allied Compounds

Silver and copper(I) complexes can be obtained from CO₂H? (CH₂)_n? S? CH₂? CH₂? S? (CH₂)_n? CO₂H when n = 1, 2, and 3 (I, II and III resp.); the compound with n = 4 (IV) fails to give these complexes. does give a silver and a copper(I) complex, while the isomeric compound again fails to give these complexes. From IV, V, and VI we prepared the corresponding disulfones.