Cycloadditionen von Heterocumulenen an CN-Bindungssysteme. 2. Mitteilung. Perhydro-s-triazindione und cyclische Aminimide aus N,N-Dimethyl-N′-dimethylamino-formamidin und Isocyanaten

The addition of the arylisocyanates 12a–12p to N,N-dimethyl-N′-dimethylaminoformamidine ( 7 ) leads to the cyclic aminimides 14a–14p . Methyl isocyanate and phenyl isotiocyanate react with 7 in an analogous manner and yield the compounds 24 resp. 30 . The arylisocyanates 12q–12v , however, which contain electron-withdrawing groups in the ortho- and/or meta-position, undergo 1,4-dipolar cycloadditions and react with the amidine 7 to furnish the perhydro-s-triazine-diones 22a–22ff . The mechanism of these reactions is discussed.     

Cycloadditionen von Heterocumulenen an CN-Bindungssysteme. 3. Mitteilung. Bildung von Dihydro-1,3,5-oxadiazin- und Perhydro-s-triazinthionen bei der Reaktion von Iminodithiocarbonaten und Azomethinen mit Aroylisothiocyanaten

The iminodithiocarbonates 5a–5g and the N-(p-methoxybenzylidene)amines 6a–61 undergo 4 + 2-cycloaddition with the aroyl isothiocyanates 4a–4f to yield the expected dihydro-1,3,5-oxadiazine-4-thiones 7, 8 and 14 . The addition of the aroyl isothiocyanates 4a–4f to the azomethines 11a–11c and 15a–15f , however, furnishes both the 4 + 2-cycloaddition products 12 and 16 and the perhydro-s-triazine-2-thiones 13a–13j . The mechanism of formation is discussed.     

Organocatalysis of CN/CN and CC/CN Exchange in Dynamic Covalent Chemistry

The reversibly formed C?N bond plays a very important role in dynamic covalent chemistry and the C?N/C?N exchange of components between different imine constituents to create dynamic covalent libraries has been extensively used. To facilitate diversity generation, we have investigated an organocatalyzed approach, using L ‐proline as catalyst, to accelerate the formation of dynamic libraries of [n×n] imine components. The organocatalysis methodology has also been extended, under somewhat modified conditions, to reversible C?C/C?N exchange processes between Knoevenagel derivatives of barbituric acid and imines, allowing for the generation of increased diversity.     

Über Chalkogenolate. 168. Reaktion von N,N′-Diphenylformamidin mit Kohlenstoffdisulfid 1. Darstellung und Eigenschaften von N,N′-Diphenyl-N-form-imidoyldithiocarbamaten

On Chalcogenolates. 168. Reaction of N,N′-Diphenyl Formamidine with Carbon Disulfide. 1. Synthesis and Properties of N,N′-Diphenyl N-Formimidoyl Dithiocarbamates N,N′-Diphenyl formamidine H? N(C₆H₅)? CH?NC₆H₅ reacts in different solvents with CS₂ in the presence of an alkali metal hydroxide to produce N,N′-diphenyl N-formimidoyl dithiocarbamate solvates. The properties of the prepared compounds (L = H₂O, acetonitrile, dioxane, dimethoxyethane, acetone, and mixed solvates) and of the Tl, Ba, and Pb salts are described.     

Synthese,Komplexbildung und Kristallstrukturen von Cyclotriphosphazenen mit N,N,N′,N′‐Tetramethylguanidingruppen

Synthesis, Complex Formation, and Crystal Structures of Cyclotriphosphazenes with N,N,N′,N′‐Tetramethylguanidine Groups The reactions of monochloropentaphenoxycyclotriphosphazene and hexachlorocyclotriphosphazene with N,N,N′,N′‐tetramethylguanidine yield the mono and tetra substituted products 2‐(N,N,N′,N′‐tetramethylguanidine)‐2,4,4,6,6‐pentaphenoxy‐2 λ⁵,4 λ⁵,6 λ⁵‐cyclotriphosphaza‐1,3,5‐trien ( 1 ) and 2,2‐dichlor‐4,4,6,6‐tetra‐(N,N,N′,N′‐tetramethylguanidine‐2 λ⁵,4 λ⁵,6 λ⁵‐cyclotriphosphaza‐1,3,5‐trien ( 2 ) respectively; no hexa functionalized product could be obtained, even with high excess of the nucleophile. Electron release from the exocyclic amino substituent reduces the acceptor ability of the phosphorus atoms. Reactions of ( 2 ) with copper(II) chloride and palladium(II) bis(acetonitrilo)dichloride yield metal complexes with a ligand : metal ratio of 1 : 2. The X‐ray structure analyses of N₃P₃Cl₂(NC(N(CH₃)₂)₂)₄ · 2 CuCl₂ ( 2 a ) and N₃P₃Cl₂(NC(N(CH₃)₂)₂)₄ · 2 PdCl₂ ( 2 b ) show that each metal atom is coordinated by two imino nitrogen atoms in geminal positions and two chloride atoms in a square planar arrangement.     

Das unterschiedliche massenspektrometrische Fragmentierungsverhalten von Lysinmethylester und dessen N,N′-Diacetylderivat. 27. Mitteilung über das massenspektrometrische Verhalten von Stickstoffverbindungen

The Different Behaviour of Lysine Methyl Ester and its N,N′-Diacetyl Derivative under Electron Impact The base peak in the spectrum of lysine methyl ester is due to the fragment ion C₅H₁₀N (m/e 84), for which the cyclic structure g (Scheme 1) is deduced. During its formation from the [M-COOCH₃]-ion an equilibration of both nitrogen atoms takes place (ion c , Scheme 1). The cyclic nature of ion m/e 84 is in agreement with the intensity of the corresponding ions in the spectra of homologues of lysine methyl ester (Fig. 1). Although in comparison with lysine methyl ester ( 1 ) N,N′-diacetyl-lysine methyl ester ( 7 ) shows the same general fragmentation pathway with formation of the ions [M-COOCH₃] and [M-COOCH₃-H₂NCOCH₃] (m/e 126), the exact fragmentation mechanism proves to the different. Two mechanisms are discussed for the formation of the ion m/e 126 from 7 (Schemes 2 and 3). The results are based on the spectra of labelled derivatives.     

Über Chalkogenolate. 169. Reaktion von N,N′-Diphenylformamidin mit Kohlenstoffdisulfid 2. Thermisches Verhalten und spektroskopische Charakterisierung von N,N′-Diphenyl-N-formimidoyldithiocarbamaten

On Chalcogenolates. 169. Reaction of N,N′-Diphenyl Formamidine with Carbon Disulfide. 2. Thermal Behaviour and Spectroscopic Characterization of N,N′-Diphenyl N-Formimidoyl Dithiocarbamates The thermal behaviour of N,N′-diphenyl N-formimidoyl dithiocarbamate solvates (L = H₂O, acetonitrile, dioxane, dimethoxyethane, acetone, and mixed solvates) have been studied by thermogravimetric analysis. The electron absorption, infrared, nuclear magnetic resonance, and mass spectra of these compounds are communicated.     

Synthesis and polymerizability of CN monomers

The synthesis and polymerizability of imine C?N monomers is surveyed. The investigated imines were either far more reactive than similarly substituted C?C or C?O monomers, or too stable to polymerize. Imines with electron‐attracting substituents on N favor polymerization by anionic mechanism, but led only to low molecular weight polymers. Imines with a donor substituent on N, such as N‐arylmethyleneimines, polymerized by cationic or anionic mechanism. 1‐ and 2‐Aza‐1,3‐butadienes were also rather unstable and polymerized to oligomers. The symmetrically substituted 2,3‐diaza‐1,3‐butadienes could be purified and polymerized successfully using anionic initiators, resulting in both 1,4‐ and 1,2‐structures in the polymer backbone, depending on the substituents. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012