Author: Gérard Schmitt

Reaction of Diphenyldiazomethane withN-Methyloxy- andN-Ethyloxycarbonyl-N-(2,2,2-trichloroethylidene)amines

Reaction of the title imines with diphenyldiazomethane gives a Δ3-1,3,4-triazoline, which leads, after loss of dinitrogen, to a transient azomethine ylide. Subsequent elimination of ethyl or methyl chloroformate gives the unexpected 1,1-diphenyl-4,4-dichloro-2-aza-1,3-butadiene.

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Nucleophilic Additions of the Cyanide Anion to 4,4-Dichloro-1,1-Diphenyl-2-Azabuta-1,3-Diene

The unexpected formation of a 2H-pyrrole by reaction of potassium cyanide with 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene and the mechanism of this reaction are described and the structures of the product and a trapped intermediate confirmed by X-ray crystallographic studies.

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Formation of (σ‐Alkenyl)‐ and (μ‐Vinylidene)palladium and ‐platinum Complexes by Oxidative Addition of 4,4‐Dichloro‐1,1‐diphenyl‐2‐azabuta‐1,3‐diene − The Molecular Structure of an Unusual Asymmetric (μ‐Vinylidene)Pd−Pd Complex

4,4-Dichloro-1,1-diphenyl-2-azabuta-1,3-diene (1) oxidatively adds to [Pd(PPh3)4] and [Pt(C2H4)(PPh3)2] giving rise to the σ-alkenyl complexes trans-[MCl{[C(Cl)=C(H)−N=CPh2]}(PPh3)2] (2a: M = Pd; 2b: M = Pt). When 1 is treated with [Pd(PPh3)4] in a 1:2 ratio in refluxing toluene, the dimetallic μ-vinylidene complex [(PPh3)ClPd{μ-[C=C(H)−N=CPh2]}PdCl(PPh3)2] (3) is formed. In this fluxional compound, a PPh3 ligands migrates in a reversible manner between the two Pd centers. Substitution of the PPh3 ligands of 3 by 2 equiv. of Ph2PCH2PPh2 affords the A-frame complex [ClPd(μ-dppm)2{μ-[C=C(H)−N=CPh2]}PdCl] (4). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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1,3-Dipolar cycloaddition of diaryldiazomethanes across N-ethoxy-carbonyl-N-(2,2,2-trichloroethylidene)amine and reactivity of the resulting 2-azabutadienes towards thiolates and cyclic amides

Abstract 1,3-dipolar cycloaddition of diaryldiazomethanes Ar2C N2 across Cl3C–CH N–CO2Et 1 yields Δ3-1,2,4-triazolines 2. Thermolysis of 2 leads, via transient azomethine ylides 3, to diaryldichloroazabutadienes [Ar(Ar')C N–CH CCl2] 4. Treatment of 4a (Ar = Ar' = C6H5) and 4c (Ar = Ar' = p-ClC6H4) with NaSR in DMF yields 2-azabutadienes [Ar2C N–C(H) C(SR)2] 5. In contrast, nucleophilic attack of NaStBu on 4 affords azadienic dithioethers [Ar2C N–C(StBu) C(H)(StBu)] (7a Ar = C6H5; 7b Ar' = p-ClC6H4). The reaction of 4a with NaSEt conducted in neat EtSH produces [Ph2C N–C(H)(SEt)–CCl2H] 8, which after dehydrochloration by NaOMe and subsequent addition of NaSEt is converted to [Ph2C N–C(SEt) C…

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Mono- and di-nuclear 2,3-diazabutadiene and 2-azabutadiene complexes of Rhenium(I): Syntheses, luminescence spectra and X-ray structures

Abstract Treatment of [Re(CO)3(THF)(μ-Br)]2 with 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene [Cl2C C(H)–N CPh2] (1a) yields the di-nuclear benzophenone azine-bridged compound [(OC)3Re(μ-Ph2C N–N CPh2)(μ-Br)2Re(CO)3] (2a), albeit in low yield. Alternatively, compounds [(OC)3Re(μ-Ph2C N–N CPh2)(μ-X)2Re(CO)3] (2a,b) (X = Br, Cl) are obtained in high yields by direct reaction of [Re(CO)3(THF)(μ-Br)]2 or [Re(CO)5Cl] with benzophenone azine. Nucleophilic attack of NaSPh on 1a affords the 2-azabutadiene derivative [(PhS)(Cl)C C(H)–N CPh2] (1b), which upon reaction with [Re(CO)3(THF)(μ-Br)]2 forms the S,N-chelate complex fac-[(OC)3ReBr{(PhS)(Cl)C C(H)–N CPh2}] (3). The crystal structures of 1b, 2…

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Reactivity of 4,4-Dichloro-1,1-diphenyl-2-azabutadiene Towards Alkoxides and Thiolates: Synthesis of Functionalised π-Conjugated 2-Azabutadienes and Unexpected 1,4-Thiazine Formation

Treatment of 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene [Cl2C=C(H)-N=CPh2] (1) with excess sodium isopropylthiolate or sodium thiophenolate in DMF yielded the 2-azabutadiene derivatives (RS)2C=C(H)–N=CPh2 (2) (2a R = iPr; 2b R = Ph). Nucleophilic attack of the sodium salt of ethyl thioglycolate on 1 afforded as the sole product the six-membered heterocyclic compound ethyl 2-ethoxycarbonylmethylthio-5,5-diphenyl-5,6-dihydro-4H-1,4-thiazine-6-carboxylate (5). The reaction is initiated by substitution of the two vinyl-bound chloro substituents to give {EtO(O=)CCH2S}2C=C(H)–N=CPh2 (2c) as intermediate. A mechanism that accounts for the subsequent cyclisation reaction is proposed. The 2-azabu…

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ChemInform Abstract: Reaction of Diphenyldiazomethane with N-Methyloxy- and N-Ethyloxycarbonyl-N-(2,2,2-trichloroethylidene)amines.

Reaction of the title imines with diphenyldiazomethane gives a Δ3-1,3,4-triazoline, which leads, after loss of dinitrogen, to a transient azomethine ylide. Subsequent elimination of ethyl or methyl chloroformate gives the unexpected 1,1-diphenyl-4,4-dichloro-2-aza-1,3-butadiene.

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Nucleophilic additions of sodium alkoxides to 4,4-dichloro-1,1-diphenyl- 2-azabuta-1,3-diene

The reaction of some sodium alkoxides with 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene is described. Whereas sodium methoxide, ethoxide or isopropoxide leads to 1,3-bis(alkoxy)- and/or 1,3,4-tris(alkoxy)-2-azabut-2-enes, the sodium salt of ethyl glycolate gives a Δ2-oxazoline. Mechanisms for the formation of these products are proposed.

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Synthesis and reactivity of an 2-azabutadiene-based π-conjugated dithioether: Formation of a N,S-ligated molybdenum chelate complex and C,N,S-pincer complexes of palladium and platinum

Abstract Nucleophilic attack of sodium isopropylthiolate on 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene [Cl2C C(H)–N CPh2}] (1) affords the 2-azabutadiene derivative [(i-PrS)2C C(H)–N CPh2] (2). Upon irradiation of Mo(CO)6 in THF in the presence of 2, the chelate complex cis-[(OC)4Mo{(i-PrS)2C C(H)–N CPh2}] (3) is obtained. Coordination on Mo occurs through the imine nitrogen and a thioether group. Polydentate dithioether 2 acts as N,C,S-pincer ligand after orthometallation reaction with Pd(II) or Pt(II). The molecular structures of 2 and (C,N,S)-[(i-PrS)2C C(H)–N C(Ph)C6H4)PtCl] (4b) have been determined by X-ray diffraction studies.

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4-Chloro-1,1-diphenyl-3-(1-pyrrolyl)-2-azabuta-1,3-diene

The title compound, C19H15ClN2, is the sole stable product resulting from nucleophilic attack of the sodium salt of pyrrole on 4,4-dichloro-1,1-diphenyl-2-azabuta-1,3-diene. The mechanism of its formation is briefly discussed.

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