Heterocycles. CII. Barriers to rotation in some N′-Heteroaryl N,N-dimethylformamidines

The free energies of activation about the =CH? NMe₂ bond in N′-heteroaryl N,N-dimethylformamidines have been found in the range from 15.6 kcal/mole to 23 kcal/mole.     

Komplexierung von Gold mit N,N-Dialkyl-N′-benzoythioharnstoffen: Die Kristallstruktur von N,N-Diethyl-N′-benzoylformamidin tetrachloroaurat (III)

Complex Formation of Gold with N,N-Dialkyl-N′-benzoylthioureas: The Crystal Structure of N,N-Diethyl-N′-benzoylformamidin-tetrachloroaurate(III) N,N-Diethyl-N′-benzoylformamidin-tetrachloroaurate(III) AuCl₄C₁₂H₁₇N₂O crystallizes in the monoclinic space group P2₁/c. The cell parameters are a = 7.764(2), b = 14.473(4) and c = 16. 105(9) Å β = 100.75(4) ⁰. The structure was solved with direct methods and refined to a final R-value of 3.38%.     

Komplexierung von Gold mit N,N-Dialkyl-N′-benzoylthioharnstoffen: Die Kristallstruktur von N,N-Diethyl-N′-benzoylthioureatogold(I)-chlorid

Complex Formation of Gold with N,N-Dialkyl-N′-benzoylthioureas: The Crystal Structure of N,N-0Diethyl-N′-benzoylthioureatogold(I) Chloride N,N-Diethyl-N′-benzoylthioureatogold(I) chloride AuCiS₁₂H₁₆N₂O crystallizes in the monoclinic space group P2₁/c. The cell parameters are a = 18.407(4), b = 5.456(1) and c = 196.322(3) Å, β = 113.6/8(1)°. The structure was solved with direct techniques and refined to final R-value of 5.92%. Gold(I) forms a monodentately sulfur-coordinated complex with the ligand N,N-Diethyl-N′-benzoylthiourea. The coordination sphere around Au(I) shows a nearly linear arrangement of sulfur and chloride.     

Die Kristallstruktur von (N,N-Diethyl-N′-benzoylselenoureato)thallium(I)

The Crystal Structure of (N,N-Diethyl-N′-benzoylselenoureato)thallium(I) . Tl(C₁₂H₁₅N₂OSe) exists in a dimeric form and crystallizes in the triclinic space group P-1. The cell parameters are a = 6.501(6), b = 9.901(7), c = 12.233(9) Å, α = 91.59(2), β = 80.11(6), γ = 85.28(5)° and Z = 2. The structure was solved with Patterson and direct methods and was refined to a final R-value of 5.30%. Two complex molecules are connected by Tl? Se bonds to form a planar four membered ring with diagonally arranged Tl and Se atoms. The considerably bended chelate rings are nearly at right angle to the central four membered ring. The Tl? Se bond lengths are 3.105(3) and 3.118(3) Å, the Tl? O bond length is 2.532(9) Å.     

Die Kristallstruktur von Tris(N,N-Diethyl-N′-benzoylselenoureato)indium(III)

The Crystal Structure of Tris(N,N-Diethyl-N′-benzoylselenoureato)indium(III) In(C₁₂H₁₅N₂OSe)₃ crystallizes in the monoclinic space group P2₁/c. The cell parameters are a = 11.792(2), b = 36.797(4), c = 18.574(2) Å, β = 92.15(2)° and Z = 4. The structure was solved with Patterson and direct methods and was refined to a final R-value of 3.41%. The asymmetric unit contains two complex molecules. The indium atoms are bidentally coordinated by three N,N-Diethyl-N′-benzoylselenourea molecules to form distorted octahedra with facial arrangement of the selenium and oxygen donor atoms. The chelate rings diverge strongly from planarity. The In? Se bond lengths vary from 2.643(1) to 2.657(1) Å, the In? O bond lengths from 2.179(4) to 2.203(4) Å, respectively.     

Die Kristallstruktur von Bis(N,N-Diethyl-N′-benzoylselenoureato)zink(II)

The Crystal Structure of Bis(N,N-Diethyl-N′-benzoylselenoureato)zinc(II) . Zn(C₁₂H₁₅N₂OSe)₂ crystallizes in the acentric orthorhombic space group Pca2₁. The cell parameters are a = 16.914(5), b = 13.492(4), c = 11.705(5) Å and Z = 4. The structure was solved with Patterson and direct methods and was refined to a final R-value of 7,05%. Zn^II is coordinated to two N,N-Diethyl-N′-benzoylselenoureato molecules, which are bidentately coordinated through their oxygen and selenium atoms to form a distorted tetrahedron. The Zn? Se bond lenghts are 2.394(3) and 2.369(4) Å, the Zn? O bond lengths are 1.971(11) and 1.974(12) Å.     

Die Kristallstruktur von Tris(N,N-Diethyl-N′ -benzoylthioureato) Rhodium(III)

Crystal Structure of Tris(N,N-Diethyl-N′-benzoylthioureato) Rhodium(III) Rh(C₁₂H₁₅N₂OS)₃ crystallizes in the trigonal space group P-3. The cell parameters are a = 16.660(2), c = 8.479(1) Å and Z = 2. The structure was solved with Patterson and direct methods and refined to a final R-value of 7.05%. Rh^III is octahedrally coordinated to three N,N-Diethyl-N′ -benzoylthiourea molecules, which are bidentately coordinated through their oxygen and sulfur atoms. The Rh? S and Rh? O bond lengths are 2.284 Å and 2.033 Å, respectively.     

Die Kristallstruktur von Bis(N,N-Diethyl-N′-benzoylselenoureato)cadmium(II)

The Crystal Structure of Bis(N,N-Diethyl-N′-benzoylselenoureato)cadmium(II) . Cd(C₁₂H₁₅N₂OSe)₂ exists in a dimeric oxygen bridged form and crystallized in the monoclinic space group P2₁/n. The cell parameters are a = 12.506(3), b = 11.563(2), c = 18.924(4) Å, β = 91.59(3)°, Z = 4. The structure was solved with Patterson and direct methods and was refined to a final R-value of 6.58%. Cadmium is coordinated by 3 oxygen and 2 selenium atoms and exhibits the unusual coordination number 5. The coordination polyhedron is a distorted trigonal bipyramid, to bipyramids are connected by a common edge. The Cd? Se bond lengths are 2.591(1) and 2.565(1) Å, the Cd? O bond lengths are 2.263(6), 2.272(5) und 2.438(5) Å.     

Barriers to internal rotation in some dimethylamino substituted azoles

Activation parameters for the hindered rotation in some dimethylamino substituted azoles are reported and the effects of various ring systems and substituents on the barrier are discussed. Possible errors in ΔH≠ and ΔS≠ are investigated.     

Barriers to rotation of the dimethylamino group in some 2-amino-4-(N,N-dimethylamino)pyrimidines

The free energy of activation for rotation about the exocyclic C? N bond of the dimethylamino group of some 6-substituted 2-amino-4-(N,N-dimethylamino)pyrmidines has been determined using ¹H NMR line shape analysis. The results are discussed in terms of the relative electron-withdrawing and electron-releasing effects of the substituents.     

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.     

Barriers to rotation in substituted O-aryl-hydroxylamines.

The effect of substituents on rotational barriers in O-arylhydroxylamines was studied. The results do not support any of the proposed mechanisms for substituent effects in the analogues sulfenamide series.     

Zum Mechanismus Massenspektrometrischer Fragmentierungsreaktionen—V: Substituenteneffekte auf Intramolekulare Substitutionen des Phenylrestes in den Massenspektren von N,N-Dimethyl-N′-Phenylformamidinen

The mass spectrum of N,N-dimethyl-N′-phenyl-formamidine (I) contains a large peak due to [M ? H]+-ions. As is shown by deuterium labelling, one of the ortho hydrogen atoms of the phenyl group is lost. The same result has been observed for the corresponding fragmentation of thioformanilide (V). This can be explained by the formation of benzimidazolium-ions (a). The effect of substituents at the phenyl group on the intensities and AP of these ions and on the IP of the molecular ions has been investigated. A mechanism of the cyclization reaction is proposed.     

Zum Mechanismus massenspektrometrischer Fragmentierungsreaktionen: XII-Einfluß einer sterischen Hinderung der Mesomerie bei der Fragmentierung von N,N-Dimethyl-N′-4-Biphenylformamidinen

The formation of cyclic [M ? H]⁺ ions (a) in the mass spectra of N,N-dimethyl-N′-arylformamidines is suppressed by electron donating groups in the aryl group para to the formamidine group, due to the participation of resonance structures of type c. This effect is also observed in the mass spectra of N,N-dimethyl-N′-4-biphenylformamidines (III) substituted in the 4′-position. By substitution in the 2-, 2′-, 6- and 6′- positions of III, the formation of resonance structure c′ in the molecular ions is so difficult that these derivatives show the normal fragmentations. This is observed with two methyl groups in the 2- and 2′- positions of III.     

Zum Mechanismus massenspektrometrischer Fragmentierungsreaktionen: XIII—Einfluß der Dissoziationsenergie auf intramolekulare aromatische Substitutionen in den Molekül-Ionen von N,N-Dimethyl-N′-phenylformamidinen

The effect of the dissociation energy of the C? X bond (X = H, F, Cl, Br, I) on the formation of benzimidazolium ions (b) by elimination of X from the molecular ions of ortho-substituted N,N-dimethyl-N′-phenylformamidines (I to V) has been investigated. No simple relation is observed between the intensities of ions b and the dissociation energy. Furthermore, the appearance potentials of ions b are not greatly affected by the dissociation energy, although differences of about 2.5 eV are expected for a simple cleavage reaction. The behaviour of the molecular ions of I to V is in accord with a two step addition-dissociation mechanism [M]⁺· → a → b, and the highest activation energy is required in the first addition step. Similar mechanisms are known for aromatic substitution reactions in the condensed phase, but have not been observed for mass spectrometric fragmentations. The detection of additional kinetic energy T in the reaction products by an analysis of the metastable transitions [M]⁺· → b corroborates the proposed mechanism.     

Synthescs and some reactions of N,N'-diamino-2,2′- and −4,4′-bipyridinium salts

The syntheses and some reaetions of N,N'-diamino-2,2′- and 4,4′-bipyridinium salts (IV, V and VI) are described. These compounds are prepared by the reaction of bipyridyls (I-III) with O-mesitylenesulfonylhydroxylamine in moderate to good yields. Compounds IV and VI were found to give the N,N'-diacyl derivatives by the reaction with acyl chlorides and to undergo 1,.3-dipolar cycloaddition reaction with an acetylenic compound to give 1:2 adducts. Photo-irradiation of N,N'-dibenzoylimino-2,2′-bipyridinium betaine (IX) isomerizes to a mono diazepine derivative (XVI).     

N,N,N′,N′‐Tetraalkylaminoazoxybenzene Derivatives; Convenient Synthesis and Mechanistic Study

N,N,N′,N′‐tetraalkyaminoazoxybenzene derivatives were conveniently prepared by the coupling of N,N‐dialkylnitrosoaniline in the presence of acetone and KOH. The reaction mechanism was proposed and investigated, and the structure of compound 3b was also confirmed by single crystal X‐ray diffractometry.     

Barriers to rotation and inversion in acyclic alkylhydrazines

Stereodynamics of acyclic hydrazines is reviewed. The energy barriers to the conformational interconversions in acyclic alkyl-hydrazines, which were observed by DNMR spectroscopy, are listed together with their assignment. The following points are emphasized: (1) The existence of two types of nitrogen inversions (the passing and the nonpassing N-inversion) in acyclic hydrazines has been confirmed: (2) the barrier to the single-passing rotation about the NN bond has recently been unambiguously determined in several hydrazines. The SCF-MO ab-initio calculations of tetramethylhydrazine have shown that the transition state of the single-passing rotation about the NN bond is in the vicinity of the conformation in which the torsion angle C-N-N-C is about 140°.     

Über Chalkogenolate. 171. Reaktion von N,N′-Diphenylformamidin mit Kohlenstoffdisulfid 4. Ester der N,N′-Diphenyl-N-formimidoyldithiocarbamidsäure

On Chalcogenolates. 171. Reaction of N,N′-Diphenyl Formamidine with Carbon Disulfide. 4. Esters of N,N′-Diphenyl-N-Formimidoyl Dithiocarbamic Acid Potassium N,N′-diphenyl N-formimidoyl dithiocarbamate reacts with alkyl halides to yield the corresponding esters \documentclass{article}\pagestyle{empty}\begin{document}${\rm C}_6 {\rm H}_5 {\rm N} = CH - {\rm N}({\rm C}_6 {\rm H}_5) - {\rm CR} - {\rm SR, where R = CH}_3,{\rm C}_2 {\rm H}_5,{\rm CH}_2 - {\rm C}_6 {\rm H}_5,$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}${\rm and (C}_6 {\rm H}_5 {\rm N} = CH - {\rm N}({\rm C}_6 {\rm H}_5) - {\rm CS)}_{\rm 2} = {\rm CH}_2 .$\end{document} The phenyl ester (R = C₆H₅) has been synthesized by reaction of N,N′-diphenyl formamidine with the phenyl ester of chlorodithioformic acid. The prepared compounds have been characterized by means of electron absorption, infrared, nuclear magnetic resonance (¹H and ¹³C), and mass spectra.     

Synthesis and characterization of N-phenylated aromatic polyureas from N,N′ -dichloroformyl-p-dianilinobenzene and N,N′ -bistrimethylsilyl-diamines

NovelN-phenylated aromatic polyureas having inherent viscosities of 0.13–0.35 dL/g were synthesized by the solution polycondensation of N,N′-dichloroformyl-p-dianilinobenzene with N,N′-bistrimethylsilyl derivatives of bis(4-aminophenyl)ether, piperazine, and p-dianilinobenzene in sulfolane. Except the polyurea containing piperazine unit, the other polyureas were amorphous and readily soluble in a variety of organic solvents such as tetrahydrofuran. The polyurea derived from p-dianilinobenzene, which has no vulnerable hydrogen on the urea linkage, did not melt below 350°C and was stable up to 450°C in air.