Organoarsen-Verbindungen. XXVI. Zur Synthese der 1.3-Azarsoline

Organo-arsenic Compounds. XXVI. Synthesis of 1.3-Azarsolines 2-Aminoalkylarsines of the type RAs(H)CH₂CH₂NH₂ react with formic acid or carbonic acid chlorides to give the corresponding amides 1–3 , whereas reaction with iminoester hydrochlorides yields 1,3-azarsolines 4–6 . I. R.- and n.m.r.-data are reported.     

Synthese und Reaktionen von 1,3-Azaphosphorinan-2-thionen

Synthesis and Reactions of 1,3-Azaphosphorinane-2-thiones Aminopropylphosphines, R P(H) (CH₂)₃ NH₂, react with carbon disulfide to give 1,3-azaphosphorinane-2-thiones. In presence of strong bases the title compounds are converted by alkyl halides into 2-alkylthio-3, 4, 5, 6-tetrahydro-1, 3-azaphosphorines whereas in absence of bases quaternization at the phosphorus atom occurs to give 2-thiono -1,3-azaphosphorinanium salts. The structures of the compounds prepared are elucidated by IR. ¹H-n.m.r. and mass spectra.     

Preparation and properties of ethoxylated fatty methyl ester nonionics

Ehthylene oxide (EO) cannot react directly with fatty methyl esters that have no active hydrogen. We developed a new synthetic method, which directly inserts EO into fatty methyl esters (RCOOCH₃) to give [RCO(OCH₂CH₂)_nOCH₃]. This was achieved by the use of a novel solid catalyst modified by metal cations. Ethoxylates of fatty methyl esters obtained by this method were homogeneous monoesters and had good properties as nonionic surfactants. Presented at the AOCS Annual Meeting & Expo in Anaheim, California, April 1993.     

P/B Ketene Adduct Formation from Acyl Chlorides at a Vicinal Phosphane/Borane Frustrated Lewis Pair

The intramolecular frustrated phosphane/borane Lewis pair Mes₂PCH₂CH₂B(C₆F₅)₂ ( 3 ) reacts with acetyl chloride to give a 1 : 1 mixture of the FLP-ketene adduct, 6a , and the FLP-HCl addition product, 7 . Similarly, the acyl chlorides phenylacetyl chloride and isobutyryl chloride react with 3 to give the respective substituted FLP ketene adducts, 6b and 6c , with HCl elimination. A series of aroyl chlorides reacts with 3 by formation of the respective aroyl-phosphonium/chloroborate zwitterions, 11a – d . The hetero-aromatic furoyl chloride reacts with 3 in a more complicated, but mechanistically probably closely related pathway, to form the 2 : 1 reaction product, 14 . Most of the products were characterized by X-ray diffraction.     

The Chemistry and Properties of a New Range of Fluorochemical Surface Active Agents

The unique properties of surface active agents which comprise a perfluoroalkyl group of about eight carbon atoms linked to a hydrophilic group have been recognised for some time. For example, such surfactants give very low surface tensions to aqueous systems, they are very effective at low concentrations, they have activity in organic systems, they are often stable in hostile environments and they can exhibit oil and water repellency when they are absorbed on substrates. Prior to the work described in this paper, the fluorochemical group for these surfactants had been made by two routes, electrochemical fluorination and telomerisation. Both of these suffer certain disadvantages so a programme of work was initiated to see whether another route to suitable perfluoroalkyl compounds could be discovered. Work in our laboratories showed that when tetrafluoroethylene is treated with fluoride ion in an aprotic solvent such as dimethylformamide, a mixture of oligomers ranging from trimers to heptamers is produced. These oligomers are highly branched unsaturated compounds. The pentamer is the most abundant and the manner in which its chemistry has been exploited to yield surfactants with a highly branched fluorochemical group (unlike those prepared by other methods) is outlined. For example, the pentamer will react with phenol or substituted phenols to give phenyl ethers, C₁₀F₁₉OC₆H₄X (X = H or a substituent). Such ethers can be converted into surface active compounds by either the introduction of hydrophilic groups onto the benzene ring (e. g. sulphonation) or by converting existing substituents into hydrophilic groups (e. g. if X = CH₃, by oxidation to COOH). Hydrophilic groups may be attached directly to the fluorocarbon by for example reacting the pentamer with a hydroxyl-ended ethylene oxide condensate (C₁₀F₂₀+HO(CH₂CH₂O)_nR→C₁₀F₁₉O(CH₂CH₂O)_nR + HF). Reaction of TFE-pentamer with inorganic nucleophiles e. g. OH-, can cause a certain amount of degradation but the products of such degradation can be used to give other surface active compounds.     

Destruction of chlorinated methanes by catalytic hydrolysis

CH₂Cl₂, CHCl₃ and CCl₄ react with water vapour to give CO₂ + HCl over-Al₂O₃, TiO₂ (rutile) and other acidic oxide catalysts; high conversions are obtained between 673 and 773 K. Rates are proportional to concentration of chlorinated methane and are inhibited by high concentrations of water; they are described by a Langmuir-Hinshelwood rate expression.     

Heterocyclen aus o-Aminoketonen. XXIII [1]. Umsetzung von o-Aminoketonen mit Dicarbonsäuren

Heterocyclic Compounds from 2-Aminoketones. XXIII. Reaction of o-Aminoketones with Dicarboxylic Acids Saturated aliphatic dicarboxylic acids (C₄ C₇ and C₁₀) react with 2-aminobenzophenones in polyphosphoric acid (PPA) to form substituted derivatives of partial hydrogenated benzo[b][1,8]naphthyridines 2a–d and 2-anilino-quinoline-3-alkanoic-acids 5a–h . The heterologous derivatives of glutaric acid — containing S or N instead of β-CH₂ — with aminoketon undergo ring closure to give thiazino- and oxazino[3,2-b]quinolines 2e–h . Aromatic o-dicarboxylic acids with a –CH₂ CO- group react with aminoketones to yield anilinosubstituted 5i or pyrano[b]-condensed quinolines 6 . N,N′-Di-(2-benzoylphenyl)-dicarboxylicacid-diamides 3 with ammonia undergo cyclisation to α,ω-di-(4′phenyl-quinazolinyl-(2′))-alkanes 4 .     

Orthoamide. LI. Push-Pull-Butadiene und Heterocyclen aus CH2-aciden Verbindungen und Orthoamiden von Alkincarbonsäuren

Orthoamides. LI. Push-Pull-Butadienes and Heterocycles from Alkyne Carboxylic Acid Orthoamides and CH₂-acidic Compounds The acetylides 4b, 4f react with N,N,N′,N′,N″,N″-hexamethylguanidiniumchloride ( 5 ) to give the orthoamides 6b, 6f , resp. From CH₂-acidic compounds and the orthoamides 6a, c, e can be obtained the push-pull-substituted butadienes 8a–8aj . The 2,3,5-trimethyl-thiadiazolium salt 9 does not condense with 6e , as other CH₂-acidic compounds do, instead the vinylogous guanidinium salt 10a is produced. On heating, the ketenaminals 8d, aa cyclize to give the pyridone-carbonitriles 11a, b , resp. From 4-amino-coumarins 12 and the orthocarboxylic acid amideacetals 13a, b and the ketenaminal 16 resp., the amidines 14a–c and the heterocyclic compounds 15a–c resp., are formed. The enamines 17a–c, 19a, b react with the orthoamides 6a–f to give the pyridine derivatives 18a–1, 20a–h and 21a, b , resp. Analogously, from 6-aminouracil 22 and 6a, b, e, f are formed the pure 7-dimethylaminopyrido[2,3-d] pyrimidines 23a, b or mixtures of compounds 23c, d and the isomeric 4-dimethylamino-pyrido[2,3-d]pyrimidines 24a, b resp., which can be separated via their salts 25a,b/26a,b . The heterocyclic compounds 30a–d, 32a,b can be prepared from the pyrazole derivatives 28, 31 resp. and the orthoamides 6a–f .     

NO Reduction by CH4in the Presence of O2over Pd-H-ZSM-5

An investigation of the interaction of NO and NO₂with Pd-H-ZSM-5, as well as the reduction of NO by CH₄, has been conducted using mass spectrometry andin situinfrared spectroscopy. Prior to reaction most of the Pd in Pd-H-ZSM-5 (Pd/Al=0.048) is present as Pd²⁺cations. NO reduction by CH₄in the absence of O₂results in the progressive reduction of Pd²⁺cations above 610 K and the formation of small Pd particles. Reduction of Pd²⁺cations is significantly suppressed when O₂is added to the feed of NO and CH₄.In situinfrared spectroscopy reveals the presence of NO⁺and NO as the principal adsorbed species. NO⁺is present as a charge-compensating cation (e.g., Z⁻NO⁺) and is believed to be formed via the reaction 2 Z⁻H⁺+2 NO+1/2 O₂=2 Z⁻NO⁺+H₂O. NO⁺does not react with CH₄at temperatures up to 773 K. Adsorbed NO reacts with CH₄above 650 K and CN species are observed as intermediates. The latter species react with both NO, O₂, and presumably NO₂. Based on the accumulated data, a mechanism is proposed to explain the reduction of NO by CH₄both in the presence and absence of O₂.     

Band-gap tuning of carbazole-containing donor-acceptor type conjugated polymers by acceptor moieties and π-spacer groups

Carbazole-containing donor-acceptor type conjugated polymers were prepared by Sonogashira cross-coupling reaction of 3,6-diethynyl-9-hexadecylcarbazole and arylene dibromides, and the optical and electrochemical properties were extensively investigated. Copolymerization with 4,7-dibromo-2,1,3-benzothiadiazole furnished the orange-colored polymer with a charge-transfer band at 440 nm in CH₂Cl₂, indicating efficient intramolecular donor-acceptor interactions. On the other hand, the color of the copolymer with 2,5-dibromopyridine was ocher and the longest wavelength absorption band was 381 nm in CH₂Cl₂, suggesting almost negligible donor-acceptor interactions. This difference was also reflected by the emission spectra, solvatochromic behaviors, and electrochemical redox potentials. Comparison of the ethynylene spacer between the donor and acceptor moieties to other π-spacers revealed that the ethynylene spacer serves as a more efficient π-spacer than vinylene and direct connection (without spacer) for strong donor-acceptor coupling in this polymer system.     

Recycling of carbon dioxide using a proton conductor as a solid electrolyte

Using a proton conductor based on SrZrO₃ or CaZrO₃ as a solid electrolyte, three attempts have been made to react CH₄ with CO₂ efficiently. When the mixture of CH₄ and CO₂ was used as a fuel gas for a SOFC, the cell provided stable electric power. Furthermore, the electrochemical hydrogen pump accelerated both the reforming of CH₄ with CO₂ and the oxidative coupling of CH₄ with CO₂.     

Synthese und Reaktionen von 2-[Bis-(alkylthio)-methyliden]-indan-1,3-dionen

Synthesis and Reactions of 2-[Bis-(alkylthio)-methyliden]-indan-1,3-diones The 2-[bis-(alkylthio)-methyliden]-indan-1,3-diones 3 and especially the methyl-compound 3a react with nucleophiles by substitution of the CH₃ S group. The reaction with amines are yields the S,N or N,N-acetales 7 and 8 , respectively. Diamines, amino hydroxy- or amino-mercapto compounds as dinucleophiles give the cyclic compounds 9 or the condensed heterocycles 12 and 16 , where the carbonyl group has been integrated in the cyclisation. Also carbanions react with 3a under substitution. The structures of the final products are determined with ir-, ¹H-n.m.r.- and ms-spectra.     

Synthese und Reaktionen carbocyclischer Acyl-keten-S,S-acetale

Synthesis and Reactions of Carbocyclic Acyl-ketene-S,S-acetales Cyclohexanone, tetralone(1) and indanone(1) react with CS₂ in the presence of bases and after methylation to 2-[bis(methylthio)-methyliden]-cyclohexanones 1,4 -tetralones(1) 2,5 and -indanones(1) 3,6 . In some cases thiophenes 8 and 9 are formed. The dimethyl-S,S-acetales 1, 2a and 3a react with mono or dinucleophiles to S,N- or N,N-acetales, with hydrazines to indazolone 22 or the pyrazole 23 . Oxidation with H₂O₂ yield disulfones 25 and 27 . The structure of products are determined by ir- and ¹H-n.m.r.-spectroscopy.     

Pyryliumverbindungen. 30. C-Alkylierung von 1,3,5-Triaryl-penten-1,5-dion-Enolaten: Ein einfacher Zugang zu 3-alkylsubstituierten 2,4,6-Triaryl-pyryliumsalzen

Pyrylium Compounds. 30. C-Alkylation of 1,3,5-Triaryl-pentene-1,5-dione Enolates: A Simple Approach to 3-Alkylsubstituted 2,4,6-Triarylpyrylium Salts 1,3,5-Triaryl-pentene-1,5-dione enolates ( 10 ), obtainable in crystalline form from 2,4,6-triarylpyrylium pseudobases ( 9 ) and sodium methoxide in benzene/ether, react in dipolar aprotonic solvents (e.g. DMSO, DMF) with various types of alkyl iodides to give C-alkylation products ( 11 ) which afford 3-substituted 2,4,6-triarylpyrylium salts ( 12 ) on treatment with perchloric acid. This reaction sequence proved to be a convenient synthetic route to pyrylium salts ( 12 ) having 3-oriented substituents such as normal or branched alkyl groups C_nH_2n+1 (e.g.n = 1–5), isotopically modified alkyl groups (e.g. C[²H₃], C₂[²H₅]), allyl type substituents (e.g. CH₂CHCH₂, MeCHCHCH₂, CH₂, CH₂CMeCH₂) or benzyl groups (e. g. PhCH₂, 4-Br C₆H₄CH₂). Bifunctional alkylating agents (e.g. 1,4-diiodobutane, o-xylylenediiodide) resulted in a novel type of bispyrylium salts ( 14 ) with 3,3′-linkage. The pyrylium salts obtained were characterized by their ¹H-n.m.r. and u.v. spectra as well as, in most cases, by transformation into the corresponding pyridine derivatives ( 13 ) and bispyridines ( 15 ) respectively.     

Stevensanaloge,Durch Nickelkomplexe Katalysierte Umlagerung Von Triarylphosphoryliden Und Darstellung Sowie Strukturbestimmung Von Phosphorylid-Nickeltricarbonylkomplexen

The Stevens rearrangement of the triarylphosphorusylids R₃ P=CHR′ (III) (R′ = H, CH₃, C₂ H₅) to diarylbenzylphosphines (V) is catalyzed by nickel complexes (e.g., (COD)₂ Ni (I)). Attempts to prepare trimesitylphosphine-methylene result in direct formation of dimesityl (mesitylmethyl) phosphine (XII) — the first recorded direct Stevens rearrangement of a phosphorusylid. Phosphorusylids react with nickeltetracarbonyl without rearrangement to give complexes of the type R₃P=CH_a · Ni(CO)₃ (XIV). The structure of XIV has been established by the IR and NMR spectra and confirmed by an X-ray structural determination.

1 B. L. Barnett and C. Krüger, J. Cryst. Mol. Struct., im Druck.

The ylid is bonded to the nickel through the C-atom with resulting hybridization from sp² towards sp³.     

Metal Induced Decarboxylation of Aliphatic Free Radicals. I. Kinetics of the Reactions of Copper(I) and Copper(II) Ions with the 2-Methyl-2-Carboxylicacid-Propyl Free Radical in Aqueous Solutions. A Pulse Radiolysis Study

CH₂C(CH₃)₂CO₂H free radicals react with Cu²⁺_aq to form Cu^III-CH₂C(CH₃)₂CO₂H²⁺_aq, which probably is rapidly transformed into intermediate I. This intermediate decomposes into Cu⁺_aq + CO₂ + CH₂=C(CH₃)₂. This is the first system in which a metal ion induced β-carboxyl elimination reaction was observed. ·CH₂C(CH₃)₂CO₂H free radicals react with Cu^III-CH₂C(CH₃)₂CO₂H²⁺_aq to form Cu²⁺_aq and a mixture of (-CH₂C(CH₃)₂CO₂H)₂, (CH₃)₃CCO₂H, and HOCH₂C(CH₃)₂CO₂H. CH₂C(CH₃)₂CO₂H reacts with Cu⁺_aq to form Cu^II-CH₂C(CH₃)₂CO₂H⁺_aq. The latter intermediate decomposes both via homolysis and by a reaction with Cu²⁺_aq to form 2Cu²⁺_aq + (CH₃)₃CCO₂H. The spectra of the intermediates and the kinetics of reaction are reported.     

Novel bimetallic lead(II) complexes of polydentate amine-phenol ligands

The polydentate amine-phenol ligands N(CH₂CH₂NHCH₂C₆H₄OH-2)₃ (H₃L¹) and (2-HOC₆H₄CH₂NH)₂C₂H₄-1,2 (H₂L²) prepared by reduction of the Schiff bases H₃saltren and H₂salen react with lead(II) acetate trihydrate to form complexes 1 and 2 respectively, both of which are dimeric in the solid state and fluxional in solution at ambient temperatures. These complexes are characterised by IR, microanalysis and single crystal X-ray diffraction.     

Organoarsen-Verbindungen. XXV. Synthese und Reaktionen von 1.3-Azarsolidin-2-thionen

Synthesis and Reactions of 1, 3-Azarsolidine-2-thiones Secondary 2-aminoethylarsines of the type RAs(H) CH₂CH₂ NHR′ react with CS₂ yielding 1,3-azarsolidine-2-thiones. Under suitable conditions the corresponding ammonium salts of the 2-arsinoethyl-dithiocarbamates are isolable as primary reaction products. 1,3-Azarsolidine-2-thiones are attacked by electrophilic agents on the sulfur atom yielding 2-alkylthio- and 2-organostannylthio-azarsolines, respectively, as well as 1,3-azarsolidine-2-ones.     

A novel route to titanium compounds containing cyclopentadienyl ligands with bromoethyl substituents; molecular structure of [(η5-C5H4CH2CH2Br)TiBr(μ-O)]4

Compounds (η⁵-C₅H₄CH₂CH₂OCH₃)TiCl₃, (η⁵-C₅H₄CH₂CH₂OCH₃)₂TiCl₂ and (η⁵-C₅H₄CH₂CH₂OCH₃)(η⁵-C₅H₅)TiCl₂ react with BBr₃ to give a high yield of titanium compounds containing cyclopentadienyl ligands with bromoethyl substituents, (η⁵-C₅H₄CH₂CH₂Br)TiBr₃ (1), (η⁵-C₅H₄CH₂CH₂Br)₂TiBr₂ (3) and (η⁵-C₅H₄CH₂CH₂Br)(η⁵-C₅H₅)TiBr₂ (4), respectively. Hydrolysis of 1 in the presence of tert-butylamine affords cyclo-[(η⁵-C₅H₄CH₂CH₂Br)TiBr(μ-O)]₄ (2) in quantitative yield. The molecular structure of 2 was determined by X-ray diffraction.     

Partial Oxidation of Methane to Synthesis Gas Over Ru-Loaded Y2O3 Catalyst

Ru-loaded Y₂O₃ catalyst was investigated for the partial oxidation of methane to synthesis gas. Ru(0.5 wt%)/Y₂O₃ catalyst afforded a high CH₄ conversion of 27% at a CH₄:O₂ ratio of 5 to give nearly a 1:2 ratio of CO and H₂ with a selectivity of 75% at 873 K. Ru(0.5 wt%)/Y₂O₃ catalyst maintained high catalytic activity over 10 h in the partial oxidation of methane. Carbon deposition of the catalyst surface in the reaction of CH₄ was examined by thermogravimetric analyses, and it was found that no carbon deposition occurred on the Ru(0.5 wt%)/Y₂O₃ catalyst. The synthesis-gas production proceeded basically via a two-step reaction consisting of methane combustion to give H₂O and CO₂, followed by the reforming of methane from CO₂ and steam.