Elimination Of Hydrogen Chloride Research Articles

Formylimin versus Isocyanat — eine ungewöhnliche Tautomerie eines Trifluoralanin‐Derivates

Formylimine versus Isocyanate — an Unusual Tautomerism of a Trifluoroalanine DerivativeThe intermediate 7a formed by hydrogen chloride elimination of 6 can easily tautomerize to the isolable isocyanate 7b. Depending on the reaction conditions nucleophiles react with 7a and 7b to give the corresponding products 8 or 9, respectively.

Synthese von (η 5-cyclopentadienyl)dichloro-s-alkoxititan(IV)-komplexen. Eine bestandsaufnahme der reaktion von titanocendichlorid mit alkoholen

The synthesis of (η 5-cyclopentadienyl)dichloro-s-alkoxititan(IV) from the corresponding alcohols and titanocene dichloride proceeds under mild conditions by substitution of one Cp ligand in the presence of triethylamine. This procedure is also applicable to chiral 1,4-t, t-diols, thus avoiding the use of the rather expensive η 5-cyclopentadienyltrichlorotitan(IV) as a starting material. The title compounds furnish the corresponding olefins by elimination of hydrogen chloride under mild conditions. The reactions of other classes of alcohols and phenols with titanocene dichloride are also investigated.

Thermal Dehydrochlorination of Poly(vinyl chloride) in Syndiotactic Systems

The thermal dehydrochlorination of syndiotactic poly(vinyl chloride) sequences has been studied theoretically on low-molecular weight models ranging from vinyl chloride dimer to pentamer using the semiempirical quantum chemical MNDO method. Parameters obtained with saturated systems and their change caused by the proceeding elimination of hydrogen chloride accompanied by the formation of the corresponding unsaturated structures are discussed with respect to the repeated chloroallyl or α-chloropolyene activation of the dehydrochlorination process. The study of the assumed radical and ionic intermediates is used in discussing the reaction mechanism of dehydrochlorination, and the radical or ionic mechanism is supposed to be operative depending on the reaction conditions.

Synthesis of fluoroaromatic compounds from the cyclopentadiene derivatives by reactions with chlorofluorocarbene under phase-transfer catalysis

The reactions of CHCl 2F with cyclopentadiene derivatives in the presence of aqueous KOH and triethylbenzylammonium chloride (TEBA) at −10 − +5∘ leads to the formation of fluoroaromatic compounds with a good yield: ▪ The synthesis involves addition of chlorofluorocarbene to dienes, resulting in corresponding cyclopropane adducts (derivatives of 6-chloro-6-fluorobicyclo[3.1.0]hex-2-ene and subsequent aromatization of the latter, proceeding via expansion of the cyclopentene ring and elimination of hydrogen chloride.

Degradation of 1,2,4-Trichloro- and 1,2,4,5-Tetrachlorobenzene by Pseudomonas Strains

Two Pseudomonas sp. strains, capable of growth on chlorinated benzenes as the sole source of carbon and energy, were isolated by selective enrichment from soil samples of an industrial waste deposit. Strain PS12 grew on monochlorobenzene, all three isomeric dichlorobenzenes, and 1,2,4-trichlorobenzene (1,2,4-TCB). Strain PS14 additionally used 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB). During growth on these compounds both strains released stoichiometric amounts of chloride ions. The first steps of the catabolism of 1,2,4-TCB and 1,2,4,5-TeCB proceeded via dioxygenation of the aromatic nuclei and furnished 3,4,6-trichlorocatechol. The intermediary cis-3,4,6-trichloro-1,2-dihydroxycyclohexa-3,5-diene (TCB dihydrodiol) formed from 1,2,4-TCB was rearomatized by an NAD-dependent dihydrodiol dehydrogenase activity, while in the case of 1,2,4,5-TeCB oxidation the catechol was obviously produced by spontaneous elimination of hydrogen chloride from the initially formed 1,3,4,6-tetrachloro-1,2-dihydroxycyclohexa-3,5-diene. Subsequent ortho cleavage was catalyzed by a type II catechol 1,2-dioxygenase producing the corresponding 2,3,5-trichloromuconate which was channeled into the tricarboxylic acid pathway via an ordinary degradation sequence, which in the present case included 2-chloro-3-oxoadipate. From the structure-related compound 2,4,5-trichloronitrobenzene the nitro group was released as nitrite, leaving the above metabolite as 3,4,6-trichlorocatechol. Enzyme activities for the oxidation of chlorobenzenes and halogenated metabolites were induced by both strains during growth on these haloaromatics and, to a considerable extent, during growth of strain PS12 on acetate.

Preparation of diastereomeric 5,8‐methanobenzoxazino[2,1–6]‐ and [2,3–6]‐1,3‐benzoxazin‐4‐ones by reaction of norbornane/ene‐condensed dihydro‐1,3‐oxazines with salicyl chloride

AbstractNorbornane and norbornene‐condensed dihydro‐1,3‐oxazines 1–6 were converted with salicyl chloride to 5,8‐methanobenzoxazino[2,1–6]‐ and ‐[2,3‐b]‐1,3‐benzoxazin‐4‐ones 7–12. The addition takes place to the C  N bond: after acylation, the intermediate is stabilized through cyclization to the aryl‐substituted carbon by hydrogen chloride elimination. Diastereomers containing the oxazine rings in isomeric positions could be isolated in two cases. This is the first example of the isolation of diastereomers in such a salicyl chloride reaction. In contrast with earlier findings with reactions of related systems, no addition to the C  C bond could be observed. The steric structures of the compounds were elucidated by ir, 1H‐ and 13C‐nmr spectroscopy.

Oxokohlenstoffe und verwandte Verbindungen; 17. Mitteilung.13-Chlor-3-cyclobuten-1,2-dion, ein hochreaktives Dienophil; einfache Synthese von Bicyclo[4.2.0]octa-1(6),3-dien-7,8-dionen und Benzocyclobutendionen

3-Chloro-3-cyclobutene-1,2-dione (1c) reacts with the dienes 3a-e on careful heating to 110 o C to afford the bicyclo[4.2.0]octa-1(6), 3-diene-7,8-dione 4a-e. The reaction pathway is explained by Diels Alder adduct formation and subsequent elimination of hydrogen chloride. 4a-e are readily oxidized by activated manganese(IV) oxide to give the benzocyclobutenediones 5a-e in good yields. The parent benzocyclobutenedione (5a) has been prepared even more conveniently in a one-pot Diels-Alder route by heating a mixture of 3-chloro-3-cyclobutene-1,2-dione (1c) and 1-acetoxy-1,3-butadiene (3f)

Suspension polymerization of vinyl chloride and the processibility of poly(vinyl chloride)

AbstractThe most important technological procedure in the production of PVC is the suspension polymerization of vinyl chloride, as processibility of the polymer may be influenced to a considerable extent by the choice of polymerization conditions. Structure heterogeneities in PVC powders manifest themselves in plasticized PVC by the occurrence of “fish eye” particles. This review concerns the formation and properties of these particles and discusses the causes of their difficult processibility. Also, the relation between polymerization process and PVC dehydrochlorination is discussed and a new mechanism of its initiation based on the reactivity of cisoid enone structures is proposed. These structures catalyze elimination of hydrogen chloride from regular units of PVC by an interchain enzyme‐like mechanism giving rise to chloroallyl structures.

Synthese und Struktur von α,β-ungesättigten aliphatischen Diazenen / Preparation and Structures of α,β-Unsaturated Aliphatic Diazenes

The reactions of 1,1,2,2-tetrafluoroethane-1,2-bisulfenyl-chloride 1 and symmetrical azines 2 yield the conjugated trans-diazenes 3 as deep-coloured solids. Unsymmetrical azines 4 react with 1 under elimination of hydrogen chloride to give 1,3-dithiolane-substituted azine derivatives as pale-coloured liquids. The crystal structure of 3b has been determined by single crystal X-ray diffraction. A participation of the phenyl group in the conjugated system is not observed in 3b.

Übergangsmetallketen-Verbindungen: XXX. Synthese von Wolframa-phospha-(oxa, thia oder aza)-Cyclopentanon-Komplexen

The addition of protic nucleophiles H 2X (X= O, S, NPh) to the phosphinoketene complexes Cp(CO)(PMe 3)ClWPR 2(Tol)C=C=O (R = Me, Ph) affords the organometallics derivatives of γ-lactones, γ-thiolactones and γ-lactames by the elimination of hydrogen chloride. Preparation and spectroscopic data of these novel chelate complexes are reported.

Metallkomplexe mit biologisch wichtigen Liganden, XLVIII [1]. Palladium(II)- und Platin(II)-Komplexe mit α,β-Dehydro- und β-Chlor-α-aminosäurederivaten sowie mit O-Acetyl-L-serin / Metal Complexes with Biologically Important Ligands, XLVIII [1] Palladium(II)- and Platinum(II)-Complexes of α,β-Dehydro- and β-Chloro-α-amino Acid Derivatives and of O-Acetyl-L-serine

The preparation and spectroscopic data of the complexes cis- and trans- CL2M(NH2C(CO2Et)=C<) , (1) (M - Pd. Pt), trans-Cl2Pd(NH2CH(CH2Cl)CO2CH3)2 (2), trans- Cl2Pd(NH2CH(CH2OAc)CO2)2 (3) and trans-Cl2Pt(Gly-β-Cl-AlaOMe)2 (4) are reported. The structures of l a and 2 have been determined by X-ray structure analysis. Elimination of hydrogen chloride from 4 gives the dehydrodipeptide complex 5.

Borderline between E1cB and E2 mechanisms. Elimination of hydrogen chloride from fluorene derivatives

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBorderline between E1cB and E2 mechanisms. Elimination of hydrogen chloride from fluorene derivativesAlf. ThibblinCite this: J. Am. Chem. Soc. 1988, 110, 14, 4582–4586Publication Date (Print):July 1, 1988Publication History Published online1 May 2002Published inissue 1 July 1988https://doi.org/10.1021/ja00222a015RIGHTS & PERMISSIONSArticle Views280Altmetric-Citations21LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (654 KB) Get e-Alerts Get e-Alerts

Novel synthesis of (−)‐trans‐Δ9,11‐tetrahydrocannabinol

AbstractAddition of hydrogen chloride gas to a solution of Δ8‐tetrahydrocannabinol in dry dichloromethane at ‐60° in the presence of zinc chloride results in the formation of a higher concentration of 9‐α‐chlorohexa‐hydrocannabinol (75%) than the thermodynamically more stable 9‐β‐chlorohexahydrocannabinol (25%). The two isomers can be separated by reverse‐phase hplc. Elimination of hydrogen chloride from 9‐α‐chlorohexa‐hydrocannabinol using potassium t‐amylate under anhydrous conditions gives exclusively Δ9,11‐tetrahydrocannabinol in overall yield of 65%.

The azeotropic dehydration and dehydrochlorination of ZrOCl 2·8H 2O

The azeotropic dehydration of ZrOCl 2·8H 2O has been carried out at 37 °C, 62 °C, 80 °C and 110 °C. The products were examined by elemental and OH analysis, IR spectroscopy and differential thermal analysis. The experimental evidence is best interpreted in terms of the formulations: [Zr 4(OH) 8(H 2O) 16]Cl 8·5H 2O, [Zr 16(OH) 34O 5(H 2O) 49]Cl 20 and [Zr 12(OH) 28O 4(H 2O) 30]Cl 12. The elimination of hydrogen chloride and the formation of terminal OH groups followed by olation in the solid state is suggested as a possible mechanism for the formation of the polymeric species.

Ungewöhnlich koordinierte Phosphorverbindungen: XXIV. Methylidinphosphan (HCP), ein neuer Cycloadditionspartner für 1,3-Dipole

Methylidynephosphane ( 2) is generated under flash pyrolytic conditions by cleavage of isobutene from the phosphaalkyne ( 1) or by elimination of hydrogen chloride from dichloromethylphosphine ( 3). It undergoes [3 + 2]-cycloaddition reactions with stable dipoles eq. diazo compounds ( 2 + 4a,b → 5a,b), methyl azide ( 2 + 7 → 8), benzonitriloxide ( 2 + 10 → 12, 1:2-adduct) and 3-methyl-2,4-diphenyl-1,3-oxazolium-5-olate ( 2 + 13 → 15) to give the corresponding phospholes. Silylated phosphaalkene ( 19) can be used as a synthetic substitute for 2: the 5-trimethylsilyl-1 H-1,2,4-diazaphospholes ( 22), which result from the reaction of 19 and the diazo compounds 4 with chlorotrimethylsilane elimination, are desilylated to 5 by potassium fluoride in dimethyl formamide.

The Molybdenum(V) Chelates Formed by the Reaction of Molydbdenum Hexacarbonyl or Molybdenum Pentachloride with Salicyl(2-pyridyl)aldazine

Abstract Reaction of molybdenum hexacarbonyl with salicyl(2-pyridyl)aldazine leads to the formation of the dinuclear compound tetra(salicyl(2-pyridyl)aldazineato)-μ-oxodioxodimolybdenum(V). Reaction of the ligand with molybdenum pentachloride gives tris(salicyl(2-pyridyl)-aldazineato)oxomolybdenum(V) which reacts with thionyl chloride to form dicholortris(salicyl(2-pyridyl)aldazineato)molybdenum(V). The dicholoride undergoes a hydrogen chloride elimination reaction with aniline to give tris(salicyl(2-pyridyl)aldazineato)-bis(anilineato)molybdenum(V). Spin Hamiltonian parameters and e.s.r spectral linewidths have been determined from the e.s.r. spectra due to the molybdenum(V)chelates. Computer simulations of the S-band e.s.r. spectrum due to the dichlorotris(salicyl(2-pyridyl)aldazineato)molybdenum(V) points to a cis configuration of the chloride anion about the molybdenum(V) centre with one chloride anion in the of the predominantly 4dxy ground molybdenum(V) centre and the other chloride anion out of tha...

Thermolyse von Arylhalogenboranen; Synthese von 1,3-Dibora- und 1,3-Borasilaindanen

The thermolysis of the 2-silylated or borylated arylboranes ( 3a-g, or 9a,b) has been investigated. The synthesis of the unknown starting boranes succeeds upon treatment of the ( o-(dichloroboryl)phenyl)trimethylsilane ( 3b) with trimethylalane (giving 3e), tetramethylstannane (giving 3f) or diisopropylamine (giving 3g) and upon trimethylation of the 1,2-bis(dichloroboryl)benzene ( 9a) with tetramethylstannane (giving 9b). In solution 3b,c, and 9a,b “dimerize” readily in a temperature range between 45 and 135°C with the liberation of halotrimethylsilanes or chloroboranes yielding the 9,10-dibora-9,10-dihydroanthracenes. The reaction mechanism is discussed. To force intramolecular reactions exclusively, flash vacuum pyrolyses (FVP) were performed at about 650°C. When pyrolyzing 3b elimination of hydrogen chloride occurs yielding 1,1-dimethyl-3-chloro-1-sila-3-boraindane ( 11). After pyrolysis of 11 at 750°C intramolecular, mutual migration of a chloro and a methyl group takes place. Possible rearrangement mechanisms are discussed and have been experimentally in investigated. Hydrogen chloride is the best leaving molecule in these pyrolyses. Extrusion of methanol (from ( o-(dimethoxyboryl)phenyl)trimethylsilane ( 3d)) or methane (from 3e) gives the corresponding borasilaindanes only at 750°C and in lower yields. The synthesis of the very sensitive 1,3-dimethyl-1,3-diboraindane also succeeds by FVP (550°C) starting with 9b. The high-field shifts of the 29Si and the 11B NMR signals of the borasilaindanes compared to the chemical shifts of the corresponding parent bora- and silaindane systems are considered as evidence for a through-bond interaction between both hetero atoms.

ChemInform Abstract: Synthesis of Permethrin Using Ester Enolate Claisen Rearrangement.

A stereoselective synthesis of 3-phenoxybenzyl ()-cis and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic acid starting from readily available 2-methyl-3-buten-2-ol() is described. Allylic rearrangement of 2-methyl-3-buten-2-ol, in the presence of acetic acid and acetic anhydride gave 3-methyl-2-butenyl acetate(). The [3,3] sigmatropic rearrangement of the allyl acetate(), as the silylketene acetal, produced the -unsaturated acid(). Treatment of 3,3-dimethyl-4-pentenoic acid() with SOCl2 followed by esterification with 3-phenoxybenzyl alcohol yielded 3, 3-dimethyl-4-pentenoic acid ester(). Addition of carbon tetrachloride to the olefin ester() furnished 4,6,6,6-tetrachloro-3,3-dimethylhexanoic acid ester (). Cyclization with potassium t-butoxide and elimination of hydrogen chloride afforded 3-phenoxybenzyl () cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic acid.

Chelated compounds and derivative of β-alkoxycarbonylalkyltin chlorides — 5-arylazo-8-quinolinolates, alizarinates, and thiocyanate: preparation and spectroscopic studies

Complex formation with chelating ligands like 5-phenylazo-8-quinolinol, 5-(2I-carboxyphenylazo)-8-quinolinol, 1,2-dihydroxyanthraquinone (i.e., alizarin), and 1-nitroso-2-naphthol is due to nucleophilic attack on tin of the β-alkoxycarbonylalkyltin chlorides (a unique class of PVC stabilizer intermediates) with the subsequent elimination of hydrogen chloride. A number of complexes of the types R2SnL2, RSnL2Cl, R2SnLCl, R2Sn(LIHI)2, R2SnLII, and RSnLIICl (where R = CH3OCOCH2CH2—, C4H9OCOCH2CH2—, and CH3OCOCH(CH3)CH2—; LH = 5-phenylazo-8-quinolinol, 1-nitroso-2-naphthol; LIHHI = 5-(21-carboxyphenylazo)-8-quinolinol; and LIIH2 = 1,2-dihydroxyanthraquinone) and a thiocyanate derivative viz. (CH3OCOCH2CH2)2Sn(SCN)2 have been prepared. 5-Arylazo-8-quinolinols exhibit azo–hydrazone tautomeric equilibria but their complexes exist only in the azo form. β-Alkoxycarbonylethyltin alizarinates are somewhat different from other complexes. In these complexes two hydroxyl groups of alizarin have been utilised in complex formation, moreover, one of the two carbonyl groups of alizarin also remains involved in coordination to tin. In (CH3OCOCH2CH2)2Sn(SCN)2, the thiocyanate group is possibly linked to tin atom through nitrogen. All the complexes and the thiocyanate derivative have been characterised by elemental analyses, electronic, ir, and 1H nmr spectra. Possible structural features of the compounds are discussed.

Competitive photodecomposition reactions of chloroiodomethane

Abstract Two different dissociation processes occur when chloroiodomethane is photolysed with laser radiation at 266.2 nm. Linear absorption leads to the cleavage of the carbon—iodine bond, while methylene radicals are formed by the absorption of two UV photons. The chemical reactions of the different photofragments are discussed. Recombination of two chloromethyl radicals leads to chemically activated 1,2-dichloroethane molecules, which either are stabilized or decompose by elimination of hydrogen chloride.