Zur Frage der Vierbindigkeit des Schwefels bei Schwefeldiimiden

Ohne Zusammenfassung

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On the question of the quadrivalence of sulphur in sulphur diimides

     

Substitutionsreaktionen an Bis(iminoboranen)

Zusammenfassung 2,2,4,4-Tetrachlorcyclodiborazane von Bis(iminoboran)-Typ geben in nicht-äther. Lösung mit Butylmagnesiumchlorid entsprechende 2,4-Dibutyl-2,4-dichlorverbindungen, mit Butyl-Li 2,2,4,4-Tetrabutylderivate. Die Azidierung von 2,2,4,4-Tetrahalogenocyclodiborazanen mit NaN₃ in CH₃CN führt zu den B-Tetrazidoverbindungen, jene von 2,4-Dihalogeno-2,4-dialkylcyclodiborazanen zu 2,4-Diazido-2,4-dialkylcyclodiborazanen. Bei großem Azidüberschuß können in 2,2,4,4-Tetraalkylcyclodiborazanen auch Halogenatome an den Iminkohlenstoffen azidiert werden. In einigen Fällen wurde Spaltung des Cyclodiborazans beobachtet.

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Substitution reactions of bis(iminoboranes)

2.2.4.4-Tetrachlorocyclodiborazanes of bis(iminoboran) type can be alkylated in non-etheric solvents to yield the corresponding 2,4-dibutyl derivates by C₄H₉MgCl while C₄H₉Li yields the tetrabutyl compounds. Reaction of 2.2.4.4-tetrahalogenocyclodiborazanes with NaN₃ in CH₃CN gives B-tetrazidocyclodiborazanes, while 2.4-dialkyl-2.4-dihalogenocyclodiborazanes lead to dialkyldiazido compounds. Upon full alkylation on the B-atoms also halogeno substituents on the imino C-atoms are substituted by N₃ using a large excess of NaN₃. In some cases splitting of the cyclodiborazane ring was observed.

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Mit 2 Abbildungen     

Metallkomplexe mit anionischen Liganden von Elementen der 4. Hauptgruppe. XI. Substitutionsreaktionen der Trichlorgermid- und Trichlorstannid-Ionen an Metalltrifluorphosphin-Komplexen

Metal Complexes with Anionic Ligands of Main Group IV Elements. XI. Substitution Reactions of Trichlorogermide and Trichlorostannide Ions with Metaltrifluorophosphine Complexes The photochemical reactions of [SnCl₃]^? in THF with the metal(0)-trifluorophosphine complexes of Ni, Fe, and Mo result in [Ni(PF₃)₃SnCl₃]^?, [Fe(PF₃)₃(SnCl₂]^?, and [Mo(PF₃)₅SnCl₃]^?. [GeCl₃]^?, in substitution reactions not as reactive as [SnCl₃]^?, does react under similar conditions with Fe(NO)₂(PF₃)₂ only, to yield [Fe(NO)₂(PF₃)GeCl₃]^?. With CpMn(PF₃)₃ (Cp = h⁵-C₅H₅) by the intermediatly formed CpMn(PF₃)₂THF both substitution derivatives [CpMn(PF₃)₂ECl₃]^? (E = Ge, Sn) are found. The metallate(0) complexes are isolated as [As(C₆H₅))₄]⁺- and [N(C₂H₅)₄]⁺ -salts; the i.r.- and ¹⁹F-n.m.r.-spectra are reported.     

Elektrophile Substitutionsreaktionen des 1,1-Difluoro-1H-cyclopropabenzols

Electrophilic Substitution Reactions of 1,1-;Difluoro-1H-cyclopropabenzene 1,1-Difluoro-1H-cyclopropabenzene ( 1 ) can be deprotonated with strong bases at C( 2 ). The resulting 1,1-di-fluoro-2-lithio-1H-cyclopropabenzene ( 2 ) reacts with electrophiles to form C( 2 )-substituted derivatives of 1 . The Diels-Alder reactions with electron-poor dienes, characteristic for 1H-cyclopropabenzene, do not occur with the 1,1-difluoro analogue 1.     

Die Konfiguration bei Substitutionsreaktionen. Chirale Synthesen

Pharmaceutical products used today need to meet high requirements if they are to be physiologically adaptable. This work depicts various synthetic methods and synthetic steps, respectively, to obtain chemically the necessary enantio purities. Most of the applied reactions proceed via an S_N2‐mechanism. The mechanisms of the Isourea‐Method, the Mitsunobu‐Inversion and the Caesium‐Effect are illustrated and elucidated as well. The applied methods are compared to each other and evaluated.     

Über einige Substitutionsreaktionen am trimeren Thioformaldehyd

Some Substitution Reactions of Trimeric Thioformaldehyde Treatment of s-trithiane with n-butyllithium results in the formation of lithium salts of carbenium ions. Their reactions with the halo-functional compounds lead to mono- or multi-substituted trithianes besides lithium chloride.     

Substitutionsreaktionen an N?Cl-Verbindungen

Substitution Reactions of N? Cl Compounds The reactions of the N? Cl compounds Trichloroisocyanuric Acid I, 1,3-Dichloroparabanic Acid II, 1,3-Dichlorohydantoin III, N-Chlorosuccinimide IV and N-Chloraceteamide V are studied with respect to some metal alkyles and metal chlorides, respectively. Substitution reactions occur with the compounds I–III which have dominant Cl^⊕-character, whereas IV and V prefer to react with SbCl₅ forming hexachloroantimonates. Some properties and vibrational informations are given.     

3,4-Dimethoxyfuran: Eigenschaften,Berechnungen und Substitutionsreaktionen

3,4-Dimethoxyfuran: Properties, Calculations and some Substitution Reactions 3,4-Dimethoxyfuran (3,4-DF) is much more reactive than furan itself. We present experimental details for the synthesis of this useful compound in 50–100 g batches. 3-4-Dibenzyloxyfuran has also been prepared. Quantum mechanical calculations by PPP-and CNDO-methods analogous to furan itself gave the following information (compared with furan): enhanced negative partial charge at C(2) and C(5), higher acidity at α-position, a stronger and at the same time inverted dipol moment. In accordance with the calculations, 3,4-DF can easily be substituted by weak electrophilic reagents, e.g. in a typical Mannich reaction. The bis-amino compound 8 is produced in good yields. Lithiation by butyl-Li leads to mono- or di-substituted products. The mono- and di-Li-3,4-DF have been used for the preparation of various acylated and alkylated 3,4-DF derivatives. By acid hydrolysis of 3,4-DF crystalline 4-methoxy-3 (2H)-furanone has been prepared.     

Katalytische Effekte bei der Reaktion von 2,4-Dinitrofluorbenzol mit Morpholin in Benzol. 7. Mitteilung über nucleophile aromatische Substitutionsreaktionen

• (1) The rates of reaction of 2, 4-dinitrofluorobenzene with morpholine have been measured in benzene solution, with and without the addition of pyridine or 1, 4-diaza-bicyclo[2.2.2]octane (DABCO) as catalysts.
• (2) The reaction is catalyzed by morpholine, pyridine and DABCO; the rate laws as functions of these bases are expressed by equations (2)–(4).
• (3) The reaction is considerably more sensitive to pyridine and DABCO catalysis than that of 2, 4-dinitrofluorobenzene with the sterically identical, but more basic piperidine. These findings confirm a previously found trend of greater sensitivity to base catalysis with decreasing base strength of the reacting amine.

     

Reaktionen vonN-Sulfinylverbindungen mit dem 1,2,4-Trithia-3,5-diborolan-Ringsystem und Substitutionsreaktionen am 1,2,4-Trithia-3,5-diborolan und 1,2-Dithia-4-aza-3,5-diborolidin

The reaction of trimethylsilyl- and pentafluorophenyl-N-sulfinylamine respectively with 3,5-dihalogeno-1,2,4-trithia-3,5-diborolanes yields the 1,2-dithia-4-aza-3,5-diborolidines1-3.Tert-butyl-N-sulfinylamine and 3,5-dimethyl-1,2,4-trithia-3,5-diborolane react analogous. OtherN-sulfinylamines however split the disulfane bridge in 3,5-dimethyl-1,2,4-trithia-3,5-diborolane and the 1,4-dithia-2-aza-3,5-diborolidines5A-7(A) are formed. Besides of boroxines, cyclo-2,4,6-trimethyl-1,3-dioxa-5-aza-2,4,6-triboranes and cyclo-2,4,6-trimethyl-1-oxa-3,5-diaza-2,4,6-triboranes are formed as byproducts,8–10 have been isolated. In 1,2,4-trithia-3,5-diborolanes and 1,2-dithia-4-aza-3,5-diborolidines the bromo-atoms can be substituted by alkyl (13, 14), by amino (15–20) and by isothiocyanato groups. The compounds were characterised analytically and spectroscopically (MS; NMR:¹H,¹¹B,¹⁹F,²⁹Si; IR).

     

Substitutionsreaktionen der Bis(trimethylelement)carbodiimide des Siliciums und Germaniums mit Metallchloriden und Dimethylmetallchloriden des Sb,Al, Ga und In

Substitution Reactions of Bis(trimethylelement)carbodiimides of Silicon and Germanium with Metal Chlorides and Dimethylmetalchlorides of Sb, Al, Ga, and In The reaction of Me₃Ge? N?C?N? GeMe₃ (Me?CH₃) with SbCl₅ in a 1 : 1 molar ratio forms dimeric Cl₄SbNCNGeMe₃ in high yields. The corresponding compounds (X₂MNCNSiMe₃)_2–3 (with X?Cl, Me and M = Al, Ga), formed by reactions of X₂MCl and Me₃SiNCNSiMe₃, are less stable and tend to condensations, eliminating Me₃SiX. The carbodiimide derivates (Me₂MNCNEMe₃)_2–3 (with E = Si, Ge) are also available in aprotic solvents from polymeric LiNCNEMe₃ and Me₂MCl (M = Al, Ga, In). According to the IR and Raman spectra the low associated substitution products consists of cyclic ring skeletons and asymmetric > N? C?N? EMe₃ units with cyanamide conformation.     

Katalytische Effekte bei den Reaktionen von 2,4-Dinitrofluorbenzol und 2,4-Dinitrochlorbenzol mit p-Anisidin in Benzol. 5. Mitteilung über nucleophile aromatische Substitutionsreaktionen

(1) The rates of the reactions of 2.4-dinitrofluorobenzene and 2.4-dinitrochlorobenzene with p-anisidine have been measured in benzene solution, with and without the addition of pyridine and 1.4-diaza-[2.2.2]-bicyclooctane (DABCO) as catalysts.     

Katalytische Effekte bei den Reaktionen von 2, 4-Dinitrofluorbenzol mit Benzylamin und N-Methylbenzylamin in Benzol. 6. Mitteilung über nucleophile aromatische Substitutionsreaktionen

• (1) The rates of reaction of 2,4-dinitrofluorobenzene with benzylamine and with N-methylbenzylamine have been measured in benzene solution, with and without the addition of pyridine or 1, 4-diaza-bicyclo[2.2.2]octane (DABCO) as catalyst.
• (2) Both reactions are catalyzed by the reacting amine, by pyridine and by 1, 4-diaza-bicyclo[2.2.2]octane.
• (3) Whereas the dependence on base concentration is linear in the case of N-methyl-benzylamine, the rate constants are curvilinearly related to base concentration in the reaction with benzylamine. Steric effects are shown to be responsible for this different behaviour, which is easily understood in terms of the two-step intermediate mechanism (eq.1) for nucleophilic aromatic substitutions.
• (4) Part of the pyridine catalysis has to be attributed to a medium effect, as can be shown directly in the reaction involving benzylamine.
• (5) The sensitivity of both reactions to base catalysis is much greater than that of the reaction of piperidine with 2, 4-dinitrofluorobenzene, but is found to be considerably smaller than in the reaction of p-anisidine with the same substrate, thus suggesting a correlation between the basicity of the reacting amine and the sensitivity of the reaction to base catalysis.