α-Funktionelle 2-Methylphenylphosphane, 2-(HE?CH2)?C6H4?PH2 (E: O,NR, PH) I. Darstellung,Metallierungs- und Silylierungsverhalten

α-Functionalized 2-Methylphenyl Phosphines, 2-(HE? CH₂)? C₆H₄? PH₂ (E: O, NR, PH) I. Preparation, Deprotonation and Silylation Behaviour By reaction of different ortho-substituted phenyl phosphonates 2-X? C₆H₄? PO₃R₂ (X = COOR, CONHR, PO₃R₂) with LiAlH₄ α-functionalized 2-methylphenyl phosphines 2-(HE? CH₂)? C₆H₄? PH₂ (E: O, NPh, PH) are accessible. The title compounds are characterized by deprotonation and silylation experiments.     

A Donor‐Stabilized Zwitterionic “Half‐Parent” Phosphasilene and Its Unusual Reactivity towards Small Molecules

The stabilization of the labile, zwitterionic “half‐parent” phosphasilene 4 L′Si?PH (L′=CH[(C?CH₂)CMe(NAr)₂]; Ar=2,6‐iPr₂C₆H₃) could now be accomplished by coordination with two different donor ligands (4‐dimethylaminopyridine (DMAP) and 1,3,4,5‐tetramethylimidazol‐2‐ylidene), affording the adducts 8 and 9 , respectively. The DMAP‐stabilized zwitterionic “half‐parent” phosphasilene 8 is capable of transferring the elusive parent phosphinidene moiety (:PH) to an unsaturated organic substrate, in analogy to the “free” phosphasilene 4 . Furthermore, compounds 4 and 8 show an unusual reactivity of the Si?P moiety towards small molecules. They are capable of adding dimethylzinc and of activating the S?H bonds in H₂S and the N?H bonds in ammonia and several organoamines. Interestingly, the DMAP donor ligand of 8 has the propensity to act as a leaving group at the phosphasilene during the reaction. Accordingly, treatment of 8 with H₂S affords, under liberation of DMAP, the unprecedented thiosilanoic phosphane LSi?S(PH₂) 16 (L=HC(CMe[2,6‐iPr₂C₆H₃N])₂). Compounds 4 and 8 react with ammonia both affording L′Si(NH₂)PH₂ 17 , respectively. In addition, the reaction of 8 with isoproylamine, p‐toluidine, and pentafluorophenylhydrazine lead to the corresponding phosphanylsilanes L′Si(PH₂)NHR (R=iPr 18 a ; R=C₆H₅?CH₃ 18 b , R=NH(C₆F₅) 18 c ), respectively.     

α-Funktionelle 2-Methylphenylphosphane, 2-(HE?CH2)?C6H4?PH2 (E = O,NR, PH). II. Komplexbildungsverhalten mit den Metallcarbonylen des Cr,Mo, W

α-Functionalized 2-Methyl Phenylphosphines, 2-(HE? CH₂)? C₆H₄? PH₂ (E = O, NR, PH) II. Coordination Behaviour with Metal Carbonyles of Cr, Mo, W The preparation of different carbonyl substituted coordination compounds (M: Cr, Mo, W) of the phosphines 2-(HE? CH₂)C₆H₄? PH₂ (E = O, NPh, PH) is described. In one case, after deprotonation of a PH₂ group a phosphine/phosphide migration of a W(CO)₅ fragment is detected.     

Zur lokalisierung funktioneller gruppen mit hilfe der massenspektrometrie—VIII : 6-hydroxy-androstan-3,17-dione und 6,17β-dihydroxy-androstan-3-one

5β-androstan-3-ones carrying a 6α-OH group show in their mass spectra a key-ion indicating the loss of water and C-1 to C-4 as C₄H₅O? particle. 6β-OH isomers lose instead C-1 to C-4 in form of C₄H₇O?.In 6α-hydroxy-androstan-3-ones differentiation between the connection of the A/B-ring system is possible, because in 5α-isomers the loss of C-3 to C-7 occurs as a C₅H₆O₂ particle, while the 5β-isomers lose the same C atoms as a C₅H₇O? unit.Compounds with a 6β-OH group in an A/B trans connected ring system show a tendency for thermal water elimination. After rearrangement of the double bond in 4,5 position the typical fragments for 3-keto-Δ⁴-steroids are obtained.Occasionally a strong influence of a 6-OH group on fragmentation reactions in the D-ring system is observed: The presence of a 6α-OH group in an androstan-3,17-dione enhances the loss of C-16 and C-17 in the form of acetaldehydenol. Also the connection of the A/B-ring system may have a considerable influence on this type of reaction: In 6,17β-dihydroxy-androstan-3-ones only by trans connection of the A/B-ring system, C-16 and C-17 are lost with high probability after water elimination.     

Unerwartete Reduktion von [Cp*TaCl4(PH2R)] (R = But,Cy, Ad,Ph, 2,4,6‐Me3C6H2; Cp* = C5Me5) durch Reaktion mit DBU – Molekülstruktur von [(DBU)H][Cp*TaCl4] (DBU = 1,8‐Diazabicyclo[5.4.0]undec‐7‐en)

Unexpected Reduction of [Cp*TaCl₄(PH₂R)] (R = Bu^t, Cy, Ad, Ph, 2,4,6‐Me₃C₆H₂; Cp* = C₅Me₅) by Reaction with DBU – Molecular Structure of [(DBU)H][Cp*TaCl₄] (DBU = 1,8‐diazabicyclo[5.4.0]undec‐7‐ene) [Cp*TaCl₄(PH₂R)] (R = Bu^t, Cy, Ad, Ph, 2,4,6‐Me₃C₆H₂ (Mes); Cp* = C₅Me₅) react with DBU in an internal redox reaction with formation of [(DBU)H][Cp*TaCl₄] ( 1 ) (DBU = 1,8‐diazabicyclo[5.4.0]undec‐7‐ene) and the corresponding diphosphane (P₂H₂R₂) or decomposition products thereof. 1 was characterised spectroscopically and by crystal structure determination. In the solid state, hydrogen bonding between the (DBU)H cation and one chloro ligand of the anion is observed.     

Diorgano-tellur-bis-(dialkylcarbamate) und -(dithiocarbamate)

Diorganyltellurium Bis-(dialkylcarbamates) and -(dithiocarbamates) Compounds of the type R₂Te(X₂CNR′₂)₂, with R ? C₆H₅, CH₃; R′ ? CH₃, C₂H₅, i-C₃H₇, c-C₆H₁₁, C₆H₅, and X ? S, are obtained by reaction of dimethyltellurium with tetraorganyl-thiuram-disulfides. Dimethyltellurium diiodide or diphenyltellurium dichloride react with sodium dithiocarbamates or with in situ prepared ammonium dithiocarbamates. Some compounds can be synthesized by reaction of diphenyltellurium oxide with amine in solutions of carbon disulfide. The synthesis of diphenyltellurium- and dimethyltellurium bis-(dimethylcarbamates) results from the interaction of diorganyltellurium diethanolate with dimethylammonium dimethylcarbamate. Decomposition reactions of the compounds in solid and solution are studied ¹H-NMR, ¹³C-NMR, and mass spectroscopically. Diorganyltellurium diethylen-bis-(N,N′-dimethyldithiocarbamates) are obtained by reaction of dimethyltellurium diiodide or diphenyltellurium dichloride and sodium ethylen-bis-(N,N′-dimethyldithiocarbamate) as polymeric products.     

4-Amino-1,5-dihydro-2H-pyrrol-2-one aus Bortrifluorid-katalysierten Umsetzungen von 3-Amino-2H-azirinen mit Carbonsäure-Derivaten

4-Amino-1,5-dihydro-2H-pyrrol-2-ones from Boron Trifluoride Catalyzed Reactions of 3-Amino-2H-azirines with Carboxylic Acid Derivatives Reaction of 3-amino-2H-azirines 1 with ethyl 2-nitroacetate ( 6a ) in refluxing MeCN affords 4-amino-1,5-dihydro-2H-pyrrol-2-ones 7 and 3,6-diamino-2,5-dihydropyrazines 8 , the dimerization product of 1 (Scheme 2). Thus, 6a reacts with 1 as a CH-acidic compound by C? C bond formation via C-nucleophilic attack of deprotonated 6a onto the amidinium-C-atom of protonated 1 (Scheme 5). The scope of this reaction seems to be rather limited as 1 and 2-substituted 2-nitroacetates do not give any products besides the azirine dimer 8 (see Table 1). Sodium enolates of carboxylic esters and carboxamides 11 react with 1 under BF₃ catalysis to give 4-amino-1,5-dihydro-2H-pyrrol-2-ones 12 in 50–80% yield (Scheme 3, Table 2). In an analogous reaction, 3-amino-2H-pyrrole 13 is formed from 1c and the Li-enolate of acetophenone (Scheme 4). A reaction mechanism for the ring enlargement of 1 involving BF₃ catalysis is proposed in Scheme 6.     

The first synthesis of dihydro-3H-pyrido[2,3-b][1,4]diazepinols and a new alternative approach for diazepinone analogues

The first synthesis of a series of 2-aryl(heteroaryl)-4-trifluoromethyl-4,5-dihydro-3H-pyrido[2,3-b][1,4]diazepin-4-ols, where aryl = C₆H₅, 4-FC₆H₄, 4-ClC₆H₄, 4-BrC₆H₄, 4-CH₃C₆H₄, 4-OCH₃C₆H₄, 4,4′-biphenyl, 1-naphthyl and heteroaryl = 2-thienyl, 2-furyl obtained from the direct cyclocondensation reaction of 4-methoxy-1,1,1-trifluoroalk-3-en-2-ones with 2,3-diaminopyridine in 54-71% yield, is reported. Another alternative and efficient route for the synthesis of a series of 2-aryl(heteroaryl)-3H-pyrido[2,3-b][1,4]diazepin-4(5H)-ones from the reaction 4-methoxy-1,1,1-trichloroalk-3-en-2-ones with 2,3-diaminopyridine, in 54-70% yield, is also reported.     

Agostic interactions as an alternative to octahedral ethylene-hydride complexes. β-CH bond activation

The geometric factors unique to βCH bond addition are discussed. Extended Hückel Molecular Orbital calculatins of the reaction profile for the conversion of [η⁵-C₅H₅Co(PH₃)C₂H₅]⁺ into [η⁵-C₅H₅Co(PH₃)(C₂H₄)(C₂H₄)H]⁺ shows that an intermediate structure with an agostic interaction is more stable than the octahedral ethylene-hydride complex. The tranformation from the agostic structure to the pentacoordinate species involves a barrier.     

Über die Bildung der Jodphosphine PH2J und PHJ2 aus Phosphin und PJ3, P2J4 bzw. J2

The iodophosphines PH₂J and PHJ₂ are formed by the reaction of PH₃ with PJ₃, P₂J₄ or J₂ respectively. They are stable only in equilibria mixtures together with PH₃, PJ₃ and P₂J₄ in the presence of HJ. H-NMR-spectra: PHJ₂ doublett ?5,03 ppm, J_{P? H} = 145 Hz, PH₂J doublett ?2,95 ppm, J_{P? H} = 168 Hz. P-NMR spectra: PHJ₂ doublett +9 ppm, J_{P? H} = 145 Hz, PH₂J triplett +156 ppm, J_{P? H} = 168 Hz. The IR-spectra of PH₂J and PHJ₂ are reported.     

Phosphanylalanes and Phosphanylgallanes Stabilized only by a Lewis Base

The synthesis and characterization of the first parent phosphanylalane and phosphanylgallane stabilized only by a Lewis base (LB) are reported. The corresponding substituted compounds, such as IDipp?GaH₂PCy₂ ( 1 ) (IDipp=1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐ylidene) were obtained by the reaction of LiPCy₂ with IDipp?GaH₂Cl. However, the LB‐stabilized parent compounds IDipp?GaH₂PH₂ ( 3 ) and IDipp?AlH₂PH₂ ( 4 ) were prepared via a salt metathesis of LiPH₂?DME with IDipp?E′H₂Cl (E′=Ga, Al) or by H₂‐elimination reactions of IDipp?E′H₃ (E′=Ga, Al) and PH₃, respectively. The compounds could be isolated as crystalline solids and completely characterized. Supporting DFT computations gave insight into the reaction pathways as well as into the stability of these compounds with respect to their decomposition behavior.     

Synthesis and solution properties of sulfate-type hybrid surfactants with a benzene ring

Nine novel sulfate-type hybrid surfactants, C_mF_2m+1C₆H₄CH(OSO₃Na)C_nH_2n+1 (FmPHnOS: m=4, 6, 8; n=3, 5, 7; C₆H₄: p-phenylene), with a benzene ring in their molecules were synthesized. Alkanoyl chlorides were allowed to react with iodobenzene in the presence of aluminum chloride to give the corresponding aromatic ketones. The reaction of the ketones with perfluoroalkyl iodides yielded 1-[4-(perfluoroalkyl)phenyl]-1-alkanones as intermediates. The intermediates were allowed to react with methanol in tetrahydrofuran in the presence of sodium borohydride to yield 1-[4-(perfluoroalkyl)phenyl]-1-alkanols. The desired hybrid surfactants were obtained by the reaction of 1-[4-(perfluoroalkyl)phenyl-1-alkanols with sulfur trioxide/pyridine complex in pyridine and by the subsequent neutralization of the products with sodium hydroxide solution. When compared with the conventional hybrid surfactants, C_mF_2m+1C₆H₄COCH(SO₃Na)C_nH_2n+1 (FmHnS: m=4, 6; n=2, 4, 6; C₆H₄: p-phenylene), the new hybrid surfactants thus synthesized were found to have a comparable ability to lower the surface tension of water and a high hydrophilicity. The cmc of FmPHnOS obeyed Kleven’s rule and their occupied areas per molecule increased with increasing m and n with the values between 0.66 and 1.05 nm². The aggregation number for FmPHnOS micelles ranged from 6 to 45 and the hydrodynamic radius of the micelles was in the range of 1.4-3.1 nm.     

B(C6F5)3-Catalyzed Aza-Friedel–Crafts Reaction of Indolizines with 2-Aryl-3H-indol-3-ones

A Friedel–Crafts reaction of indolizines with 2-aryl-3H-indol-3-ones catalyzed by B(C₆F₅)₃ is described. This protocol gives access to indolizine derivatives that are valuable building blocks in synthetic and pharmaceutical chemistry. The reaction proceeds under mild conditions, affording various C2-quaternary indolin-3-ones based on indolizine with high yields and regioselectivities. Moreover, the synthetic transformations of the target products were realized by N-methylation and trifluoromethane sulfonation.     

The preparation and x-ray structure of [P(C2H5)4]+[N3]− and the attempted preparation of [PH4]+[N3]−

Tetraethylphosphonium azide, [P(C₂H₅)₄ ]⁺[N₃ ]⁻, was prepared from tetraethyl phosphonium bromide and silver azide. Single crystals of [P(C₂H₅)₄ ]⁺[N₃ ]⁻ were grown from dichloromethane/THF (10:1) solution. The structure was determined by single-crystal X-ray diffraction analysis. [P(C₂H₅)₄ ]⁺[N₃ ]⁻ crystallizes in the monoclinic space group C 2/c with Z = 4 and unit cell dimensions a = 12.961(6), b = 6.835(3), c = 12.378(6) Å, and β = 100.57(4)°. The attempted preparation of phosphonium azide [PH₄]⁺[N₃]⁻ from phosphonium iodide and silver azide lead instead to the formation of PH₃ and HN₃. The instability of [PH₄]⁺[N₃]⁻ with respect to PH₃ and HN₃ is in accord with thermodynamic considerations according to which the reaction PH₃(g) and HN₃(g) to yield [PH₄ ]⁺[N₃ ]⁻ is thermodynamically unfavorable. (Non SI units employed: kcal ≈ 4.184 J, Å = 10⁻¹⁰ m.) © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:129–132, 1998     

Funktionell substituierte zinnorganische verbindungen v. st]Phosphono- Und phosphonylmethyl-triorganostannane

The synthesis of phosphono- and phosphonylmethyl-triorganostannanes R₃SnCH₂P(O)(OR′)R′′ (R′′  OR′, C₆H₅) via an Arbuzov reaction of R₃SnCH₂I with P(OR′)₃ or C₆H₅P(OR′)₂ (R′′  CH₃, C₂H₅) is described. The new compounds have been studied with regard to their behaviour towards electrophilic (Br₂, HCl, HgBr₂) and nucleophilic (NaOH, LiAlH₄, LiR) agents. Their reaction with chlorophenylphosphines followed by reduction with LiAlH₄ yields the unsymmetrical methylenebis(phosphines) C₆H₅P(R)CH₂PH₂ (R  H, C₆H₅). The title compounds add to the carbonyl group of aldehydes and the CN bond of phenylisocyanate.     

1,3-Dipolar cycloadditions of diazoalkanes to pyridazine derivatives. Thermal 1,5-sigmatropic rearrangement of methyl groups in 3,3-dimethyl-3H-pyrazolo[3,4-d]pyridazine derivatives

Thermal 1,5-sigmatropic rearrangements of one of the methyl group attached at position 3 of 3,3-dimethyl-3H-pyrazolo[3,4-d]pyridazin-4(5H)-ones 1–3 taking place either in a clock-wise or anti-clockwise direction gave N₂-methylated products 4–6 and C_3a-methylated products 7– 9 . The -7(6)-one derivative 10 and -4,7(5H,6H)-dione derivative 12 gave only N₂-methylated products 11 and 13 respectively, and 1,2-dihydro derivative 14 produced after elimination of methane, 15 .     

Antimon-organo-Verbindungen. VI. Kristallines „Phenylantimon”︁ Bildung und Spaltung mit Natrium bzw. Lithiumbutyl

Organoantimony Compounds. VI. Crystalline Phenyl Antimony. Formation and Cleavage with Sodium and Lithium Butyl, respectively Reactions of C₆H₅SbH₂ with C₆H₅CH ? CH₂, C₆H₅C ? CH and other unsaturated compounds give the corresponding hydrogenated system and phenyl antimony as orange-red crystals and the formula (C₆H₅Sb)₆ · 1 C₆H₆ 1.1 reacts with sodium by cleavage of Sb–Sb bonds forming C₆H₅SbNa₂ and C₆H₅(Na)Sb–Sb(Na)C₆H₅. These stibides are suitable materials to prepare tert. stibines, distibines and cyclic stibines. The cleavage of 1 with butyllithium is a complicated reaction and gives beside other stibides also C₆H₅(C₄H₉)SbLi which can be characterized as (CH₃)₃Si–Sb(C₄H₉)C₆H₅. The ¹H-nmr data of the prepared stibines are discussed.     

Darstellung von C6H5M(CO)5 (M = Mn,Re) und ortho-metallierten Ketonen mit einem Mangan- bzw. Rhenium-Ringglied

Preparation of C₆H₅M(CO₅ (M = Mn, Re) and Ortho-Metallated Ketones with a Manganese or Rhenium Ring Member C₆H₅Mn(CO)₅ and C₆H₅Re(CO)₅ were obtained by a new preparation method by a photochemical reaction between M₂(CO)₁₀ (M = Mn, Re) and (C₆H₅)₂Hg. The reaction of C₆H₅Mn(CO)₅ with (CH₃)₂Hg at different reaction conditions yielded the o-metallated benzophenone or the acetophenone; such known o-metallated derivates were prepared as yet by a reaction between the ketones and CH₃Mn(CO)₅. The ortho-metallated ketones and or were reaction products between Mn₂(CO)₁₀ and R₂Hg (R?C₆H₅ or p-(CH₃)₂NC₆H₄). On the contrary Re₂(CO)₁₀ and (C₆H₅)₂Hg were capable to form the analogous ortho-metallated benzophenone derivatives only by an addition of benzophenone. A substitution reaction of a CO ligand by P(C₆H₅)₃, a fission of the five-membered heterocyclic ring and a phenylation was carried out for some of such o-metallated ketones. The products were characterized by infrared spectroscopic measurements.     

Antimon-organo-Verbindungen. V. Zum Reaktionsverhalten des Phenylstibins

Organoantimony Compounds. V. The Reactivity of Phenyl Stibine C₆H₅SbH₂, synthesized by the reduction of C₆H₅SbCl₂ with LiBH₄, reacts with LiR under certain conditions forming (C₆H₅Sb)_n and H₂ or give by a partially elimination of H₂ stibides with a different structure. The latter react with alkyl and aryl halides forming tert. stibines which may be characterized as the corresponding dibromides. The preparation of C₆H₅SbNa₂ and its reaction with C₂H₅Br, Cl(CH₂)₄Cl and C₆H₅(Cl)C?N? N?C(Cl)C₆H₅ are described.     

Synthesis and Spectroscopic Studies of Arylethynylsilanes

A variety of arylethynylsilanes (Ar‐C?C? C₆H₄? C?C)_nSiMe_4?n were prepared successfully by reaction of the corresponding chlorosilanes Me_4?nSiCl_n with Ar? C?C? C₆H₄? C?CM (M=Li, MgBr), which was prepared by treatment of ethynyl(diarylethyne)s Ar? C?C? C₆H₄? C?CH with BuLi or MeMgBr. The ethynyl(diarylethyne)s were readily prepared in good yields by the double‐elimination method: addition of lithium hexamethyldisilazide to a mixture of ArCH₂SO₂Ph, TMS? C?C? C₆H₄? CHO, and ClP(O)(OEt)₂, followed by desilylation. In the tetrakis(arylethynyl)silanes (Ar? C?C? C₆H₄? C?C)₄Si thus prepared, through‐space conjugation of four triple bonds on the silicon atom emerges as a result of participation of the silicon orbitals in the acetylenic π orbitals. This participation enhances the emissive quantum yields of arylethynylsilanes with an increase in the number of arylethynyl moieties on silicon: quantum yields of emission (Φ_F) of 0.72 for (MeOC₆H₄? C?C? C₆H₄? C?C)₄Si, 0.53 for (MeOC₆H₄? C?C? C₆H₄? C?C)₂SiMe₂, and 0.47 for MeO‐C₆H₄? C?C? C₆H₄? C?CSiMe₃ were obtained. Although this enhancement effect was also observed in the phenylethynylarylsilane (MeOC₆H₄? C?C? C₆H₄)₂SiMe₂, the bis(arylethynyl)disilane (MeOC₆H₄? C?C? C₆H₄? C?C‐SiMe₂)₂ exhibited non‐enhanced emission.