Synthesis und Reaktivität von Dimethylaminoalkylidenaminooxy-arsinen

Synthesis and Reactivity of Dimethylaminoalkylideneaminooxiarsines The reactions of As[N(CH₃)₂]₃ with oximes result in the formation of the oximates [(CH₃)₂N]₂AsONCRR′, (CH₃)₂N As(ONCRR′)₂ and As(ONCRR′)₃. The eleavage of the As-N-bond with alcohols, thiols and diols are described. The reactions of CH₃As[N(CH₃)₂]ONCRR′ with water, amine and alcohols are examined. IR-and ¹H-NMR-spectral data are presented.     

Zur Synthese und Reaktivität Triflatsubstituierter Siloxanderivate

Synthesis and Reactivity of Triflate Substituted Siloxane Derivatives The reaction of amino substituted siloxane derivatives with trifluoromethanesulfonic acid leads under elimination of ammonium trifluoromethanesulfonate to the formation of siloxanyl triflates. The compounds are characterised by NMR-spectroscopy (²⁹Si, ¹³C, ¹H). The synthetic potential of these siloxanes is shown on selected examples. One interesting point of view is the synthesis of silicon containing oligo- and polymeres, in which siloxane and silylenealkine units are combined.     

Struktur und Reaktivität eines Triazolobenzodiazepin/Oxalylchlorid-Addukts

Structure and Reactivity of a Triazolo-benzodiazepine/Oxalyl Chloride Adduct Reaction of oxalyl chloride with N, N-dimethyl-{8-chloro-6-(0-fluorophenyl)- 4H, 11 H-[1,2,4]triazolo [1,5-α] [1,4]benzodiazepine}-2-carboxamide ( 6a ), the syn-thesis of which is described, leads to the cyclic adduct N, N-dimethyl-{2,12,12-trichloro-13a-(0-fluorophenyl)-11-oxo-10,11,12,13a-tetrahydro-5H, 9H-[1,3]oxazolo [3,2-d] [1,2,4]triazolo [1,5-a] [1,4]benzodiazepine}-7-carboxamide ( 7a ). Upon thermolysis 7a is partly reconverted to the starting diazepine 6a via loss of the elements of oxalyl chloride. Reduction of 7a with sodium borohydride also yields 6a in addition to its dihydro derivative 9 . Energetic treatment of 7a with sodium methoxide leads to the unexpected methoxydiazepines 10a and 10b , and mild treatment of 7a with sodium methoxide to the stereoselective formation of the two precursors of 10 , namely the chloromethoxy derivative 11 and the dimethoxy derivative 12 . Epimerization of 11 followed by nucleophilic substitution gives a mixture of two dimethoxy compounds, 12 and its epimer 14 . The configurational assignments of these derivatives are based upon X-ray analysis of 12 . A possible pathway for this unexpected substitution reaction is proposed.     

Bisaminophosphane – Synthese,Struktur und Reaktivität

Bisaminophosphanes – Synthesis, Structure, and Reactivity Different pathways for the synthesis of bis(alkylamino)phosphanes RP(N(H)R′)₂ are described. t‐BuP(N(H)‐ Dipp)₂ (Dipp = 2,6‐i‐Pr₂–C₆H₃) was structurally characterized by single crystal X‐ray diffraction. The reactivity of the compounds was examplarily investigated using t‐BuP(N(H)t‐Bu)₂. Its reaction with Me₃Al and R₂AlH (R = Me, Et, i‐Bu) in 1 : 1 and 1 : 2 stoichiometrie yield monosubstituted compounds of the type t‐BuP(N(H)t‐Bu)(N(AlR₂)t‐Bu).     

Synthese und ungewöhnliche Reaktivität eines Cyclotrisilans

Reductive coupling of dichlorosilane 1 with magnesium yields the stable, highly moisture sensitive cyclotrisilane 2a. The hydrolysis products, 1,3-siloxanediol 3 and disilane 4 corroborate the proposed structure of 2a. The reaction with typical silylene trapping agents like benzyl, benzophenone or 2,2′-bipyridyl results in cleavage of all three endocyclic bonds of 2a, yielding the formal silylene addition products 8, 9 and 10.