- Preparation method of 3, 3-dimethyl-1-butyne
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The invention discloses a preparation method of 3, 3-dimethyl-1-butyne, which comprises the following steps: by using tert-butyl alcohol and acetylene which are simple, readily available and cheap as initial raw materials and using transition metal salt which is readily available on the market as a catalyst, directly reacting in the presence of acid to obtain a product, and carrying out simple distillation separation to obtain a high-purity product. The method is simple and convenient to operate, less in environmental pollution, good in product quality, high in yield, low in cost and more suitable for industrial production.
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Paragraph 0028-0031; 0034-0043
(2021/04/17)
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- Synthesis method of terbinafine medical intermediate tert-butyl acetylene
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A synthesis method of terbinafine medical intermediate tert-butyl acetylene includes the following steps of adding 310 ml of potassium bisulfite solution and 300 ml of potassium bisulfite to a reaction vessel provided with a stirrer, a thermometer, a dropping funnel and a condenser, raising the temperature of the solution to 90-95 DEG C, controlling the stirring speed at 150-170 rpm, dropwise adding 0.73 mol of 1,1-diamido-3,3-dimethylbutane, controlling the dropwise adding time at 3-5 hours, adding 0.81-0.84 mol of hypochloric acid phenyl ester, conducting reaction for 90-120 min, raising the temperature of the solution to 110-115 DEG C, continuing to conduct reaction for 3-5 hours, lowering the temperature of the solution to 10-15 DEG C, separating out solid, conducting filtering, saline solution washing, acetonitrile washing and pressure reduction distillation, collecting fraction of 100-108 DEG C, and conducting recrystallization in cyclohexane to obtain crystal tert-butyl acetylene.
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Paragraph 0015; 0016
(2017/03/14)
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- Lanthanide-Catalyzed Reversible Alkynyl Exchange by Carbon–Carbon Single-Bond Cleavage Assisted by a Secondary Amino Group
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Lanthanide-catalyzed alkynyl exchange through C?C single-bond cleavage assisted by a secondary amino group is reported. A lanthanide amido complex is proposed as a key intermediate, which undergoes unprecedented reversible β-alkynyl elimination followed by alkynyl exchange and imine reinsertion. The in situ homo- and cross-dimerization of the liberated alkyne can serve as an additional driving force to shift the metathesis equilibrium to completion. This reaction is formally complementary to conventional alkyne metathesis and allows the selective transformation of internal propargylamines into those bearing different substituents on the alkyne terminus in moderate to excellent yields under operationally simple reaction conditions.
- Shao, Yinlin,Zhang, Fangjun,Zhang, Jie,Zhou, Xigeng
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supporting information
p. 11485 - 11489
(2016/10/24)
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- "quick and click" assembly of functionalised indole rings via metal-promoted cyclative tandem reactions
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An efficient and convenient synthesis of a variety of decorated indoles using a three-component tandem metal-catalysed process is described. We propose here a new "synthetic kit" that allows for the "quick and click" assembly of indole rings using readily available, and inexpensive starting materials under environmentally friendly reaction conditions. This journal is
- Capitta, Francesca,De Luca, Lidia,Porcheddu, Andrea
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p. 59297 - 59301
(2015/02/19)
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- Substituent effects on the photorearrangements of unsymmetrically substituted diazinobarrelenes
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A series of diazinobarrelenes 8-15 engendered with alkyl functionalities at the barrelene skeleton were irradiated with 350 nm light under direct and acetone-sensitized reaction conditions. Under these conditions, all the barrelenes except barrelene 14 afforded semibullvalenes with varying degrees of regioselectivity and product distribution. Dicyanopyrazinobarrelenes 8-10 which furnished semibullvalenes 32-41via the aryl-vinyl initial bridging route were strongly controlled by the nitrile functionalities installed at the aromatic sites. Benzoquinoxalinobarrelenes 11-13 which afforded semibullvalenes 42-49, preferentially underwent photorearrangement via vinyl-vinyl bridging even if the compounds were excited at a wavelength where the quinoxaline moiety absorbed most of the light. Zimmerman's bridging hypothesis and the possibility for quinoxalines to undergo intramolecular triplet energy transfer could reasonably account for the observed regioselectivity. Barrelene 14 was insensitive to photorearrangement whereas benzo[f,h]quinoxalinobarrelene 15 preferentially underwent ADPM rearrangement affording semibullvalenes 50-52. Electronic and steric factors of alkyl substituents overwhelmingly controlled the product forming steps whereas localization and minimization of triplet energies greatly influenced the initial bridging interaction. The Royal Society of Chemistry 2013.
- Hsieh, Hsing-Pang,Chen, Ann-Cheng,Villarante, Nelson R.,Chuang, Gary J.,Liao, Chun-Chen
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p. 1165 - 1178
(2013/03/14)
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- Weakly nucleophilic conjugate bases of superacids as powerful nucleophiles in vinylic bimolecular nucleophilic substitutions of simple β- alkylvinyl(aryl)-λ3-bromanes
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We report herein, for the first time, the stereoselective synthesis of simple (E)-β-alkylvinyl(aryl)-λ3-bromanes via a boron-λ3-bromane exchange reaction and their unique bimolecular nucleophilic substitutions at the vinylic ipso carbon atom under mild conditions. Interestingly, even weakly nucleophilic anions such as conjugate bases of superacids (HBF4, TfOH, Tf2CH 2, Tf3CH, Tf2NH, etc.) function as nucleophiles toward the vinyl-λ3-bromanes. For instance, the vinylic SN2 reaction of (E)-vinyl-λ3-bromanes with potassium bis(triflyl)methanide stereoselectively produced (Z)-vinyloxy oxosulfonium ylides with exclusive inversion of configuration via oxygen attack, while that with potassium bis(triflyl)imide afforded predominantly (Z)-vinyloxysulfoximines. In marked contrast, (E)-β-alkylvinyl- λ3-iodanes do not undergo the vinylic SN2 reaction with these conjugate bases of superacids. The differences between the nucleofugalities of aryl-λ3-iodanyl and aryl- λ3-bromanyl groups (the latter being greater) probably play a pivotal role in these unique reactions.
- Ochiai, Masahito,Okubo, Takuji,Miyamoto, Kazunori
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supporting information; experimental part
p. 3342 - 3344
(2011/05/04)
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- Thieme Chemistry Journal Awardees - Where are they now? A general one-step synthesis of alkynes from enolisable carbonyl compounds
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Terminal and internal acetylenes were obtained in good to excellent isolated yields from carbonyl compounds by converting the carbonyl functionality into the enol nonaflate intermediate followed by elimination to give the C-C triple bond. The one-pot transformations were uniformly induced by phosphazene bases combined with mildly electrophilic nonafluorobutane-1-sulfonyl fluoride. The method is the most general among those reported to date as it applies to both acyclic ketones and aldehydes. Only moderate kinetic regioselectivity in favour of alk-1-yne achieved from methyl n-alkyl ketone represents a limitation of the method. In all the other instances, individual acetylenic products were obtained. Georg Thieme Verlag Stuttgart.
- Lyapkalo, Ilya M.,Vogel, Michael A. K.,Boltukhina, Ekaterina V.,Vav?ík, Ji?í
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scheme or table
p. 558 - 561
(2009/07/09)
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- Removal of water - a factor influencing the synthesis of alkynes in a phase-transfer catalyzed β-elimination reaction
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Acetylene derivatives 4 were synthesized from the corresponding vicinal bromo compounds 2 in the phase-transfer catalyzed hydrogen bromide β-elimination reaction using solid potassium hydroxide as a base, xylene as a solvent, and a phase-transfer catalyst. The yields of the synthesized acetylene derivatives 4 were substantially improved when water formed in the process had been removed.
- Zakrzewski,Huras,Sas,Zelechowski,Bombinska
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p. 1051 - 1057
(2008/09/21)
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- Reaction of C-silylated α-diazophosphines as nucleophiles toward carbonyl compounds: A mechanistic study and application to the synthesis of alkynes and α-hydroxyphosphonamides
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Diversely substituted α-hydroxyphosphonamides and alkynes have been efficiently synthesized through the reaction of C-silylated α- diazophosphines with different types of aldehydes (2 equiv) in a neutral medium under very mild conditions. The reaction with some chiral aldehydes is highly diastereoselective leading to phosphonamides as single diastereomers. The novel reaction is influenced by electronic and steric effects being precluded for aromatic aldehydes containing electron-releasing substituents on the phenyl ring and for bulky aliphatic aldehydes. The mechanistic studies of these processes, which are highly exothermic, provide evidence for a nucleophilic attack of the diazophosphine to the aldehyde leading to a betaine that rapidly rearranges to a diazomethylenephosphorane, which has been detected or captured in some instances. The diazomethylenephosphorane reacts with a second molecule of aldehyde according to a Wittig-type condensation, and the rate-determining step of the whole process is believed to be the decomposition of the resultant oxaphosphetane to afford the hydroxyphosphonamide and a diazocumulene. Finally, this intermediate loses molecular nitrogen giving a transient carbene that rapidly evolves toward the alkyne.
- Illa, Ona,Bagan, Xavier,Cazorla, Anna M.,Lyon, Celine,Baceiredo, Antoine,Branchadell, Vicenc,Ortuno, Rosa M.
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p. 5320 - 5327
(2007/10/03)
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- Regioselective synthesis of novel heterophanes from 4-amino-triazoles
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The regioselective synthesis of N-amino-benztriazolophanes has been achieved by incorporation of benzene nucleus in the heterophane. The some of the novel compounds have been studied for their use as PTC agents.
- Chande, Madhukar S.,Athalye, Shailesh S.,Godbole, Ajit A.
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p. 670 - 673
(2007/10/03)
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- A new, efficient method for direct α-alkenylation of β-dicarbonyl compounds and phenols using alkenyltriarylbismuthonium salts
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Direct α-alkenylation of β-keto esters, β-diketone, and phenols with alkenyltriarylbismuthonium salts proceeded smoothly in the presence of 1,1,3,3-tetramethylguanidine to afford the corresponding α-alkenylated carbonyl compounds (β,γ-unsaturated carbonyl compounds) in good yields. The high leaving ability of the triarylbismuthonio group is a key driving force to achieve the C-C bond formation at the vinylic carbon under mild conditions.
- Matano, Yoshihiro,Imahori, Hiroshi
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p. 5505 - 5508
(2007/10/03)
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- Compositions and methods for hydration of terminal alkynes
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Compositions and methods are described for hydrating terminal alkynes catalytically in anti-Markovnikov fashion. The compositions comprise a transition metal complex including at least one organic ligand having at least two heteroatoms, wherein the heteroatoms are directly bonded or located one atom away. Preferably, at least one of the heteroatoms is nitrogen, which is typically provided as part of a heterocyclic ring. Other preferred heteroatoms include S, P, N, As or Se. A particularly preferred catalyst employs a P-linked imidazole ligand bound to Ru. Such complexes have a controlled adaptable proton transfer ability and/or a hydrogen bonding ability making them particularly useful as chemical reaction facilitators.
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- Synthesis and structural studies of novel 1,3,4-oxadiazolophanes
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The title compounds have been prepared in moderate yields from compound 2a/2b as starting unit, which are obtained, in good yields by one-step process in high purity. Interesting results have been obtained when the cyclisation products were studied for structural analysis. The title compounds are also studied for their use as PTC agents.
- Chande, Madhukar S.,Godbole, Ajit A.,Coutinho, Evans,Desai, Prashant
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p. 397 - 400
(2007/10/03)
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- Alkylation of acetylene by tert-butyl alcohol
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A reaction of acetylene with tert-butyl alcohol in the presence of sulfuric acid leads to tert-butylacetylene.
- Kazakov,Demina
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p. 2134 - 2135
(2007/10/03)
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- Compositions and methods for hydration of terminal alkynes
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Compositions and methods are described for hydrating terminal alkynes catalytically in anti-Markovnikov fashion. The compositions comprise a transition metal complex including at least one organic ligand having at least two heteroatoms, wherein the heteroatoms are directly bonded or located one atom away. Preferably, at least one of the heteroatoms is nitrogen, which is typically provided as part of a heterocyclic ring. Other preferred heteroatoms include S, P, N, As or Se. A particularly preferred catalyst employs a P-linked imidazole ligand bound to Ru. Such complexes have a controlled adaptable proton transfer ability and/or a hydrogen bonding ability making them particularly useful as chemical reaction facilitators.
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- Preparation of preparing substituted indanones
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a process for the preparation of indanones of the formula II from, indanones of the formula I or of indanones of the formula IIa from indanones of the formula Ia comprises reacting an indanone of the formula I or Ia with a coupling component.
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- Synthesis and characterization of coordinatively unsaturated alkynyl- and aryl-cobalt complexes with 15 valence electrons, TpiPr2Co-R, bearing the hydrotris(3,5-diisopropylpyrazolyl)borato ligand (TpiPr2)
-
Coordinatively unsaturated 15e alkynyl- (TpiPr2Co-C≡C-R) and aryl-cobalt complexes (TpiPr2Co-aryl) bearing the hydrotris(3,5-diisopropylpyrazolyl)borato ligand (TpiPr2) are prepared by dehydrative condensation of the hydroxo complex [TpiPr2Co(μ-OH)2]2 with 1-alkyne and arylation of the chloro complex TpiPr2Co-Cl with Grignard reagents, respectively. Spectroscopic and crystallographic analyses reveal the apparent C3-symmetrical tetrahedral structures with high-spin electronic configuration (S = 3/2), which should result from the property of the TpiPr2 ligand as a tetrahedral enforcer. The TpiPr2Co and hydrocarbyl fragments, are connected dominantly through σ-bonding interaction, and π-interaction including back-donation is not significant as revealed by EHMO calculations. The Co-C bonds are so polarized as to be readily protonated even by moisture to give the corresponding hydrocarbons, but the reactivity toward unsaturated hydrocarbons turns out to be sluggish. TpiPr2Co-C≡C-COOMe is found to catalyze a rare example of specific linear trimerization of methyl propiolate to give (E,E)-MeOOC(H)C=CH-CH=C(COOMe)-C≡C-COOMe.
- Yoshimitsu, Shin-Ichi,Hikichi, Shiro,Akita, Munetaka
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p. 3762 - 3773
(2008/10/08)
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- Process for the preparation of cyclopropylacetylene
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The present invention relates generally to novel methods for the preparation of cyclopropylacetylene which is an essential reagent in the asymmetric synthesis of (S)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4-dihydro-2H-3,1-benzoxazin-2-one; a useful human immunodeficiency virus (HIV) reverse transcriptase inhibitor with superior anti-retroviral activity. In the process, for example, cyclopropane carboxaldehyde is alkylated to form 1,1,1-trichloro-2-cyclopropyl-ethanol; which in turn undergoes elimination to form 1,1-dichloro-2-cyclopropyl-ethene; which in turn undergoes elimination to form cyclopropyl acetylene.
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Page column 13, 15-16
(2008/06/13)
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- Thermal decomposition of alkenyliodonium tetrafluoroborates: A novel route to fluoroalkenes
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Alkenyl(phenyl)iodonium tetrafluoroborates dissolved in chloroform, or in the solid state, decompose thermally at 60°C to yield fluoroalkenes and iodobenzene as major products via an S(N)1- or S(N)2-type reaction within the ion pair of the substrates. (C) 2000 Elsevier Science Ltd.
- Okuyama, Tadashi,Fujita, Morifumi,Gronheid, Roel,Lodder, Gerrit
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p. 5125 - 5129
(2007/10/03)
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- A new and practical synthesis of vinyl dichlorides via a non-Wittig-type approach
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A practical approach for the conversion of aldehydes to vinyl dichlorides has been developed. These are three-step, one-pot reactions involving the formation of trichlorocarbinol by treatment of aldehydes with trichloroacetic acid and sodium trichloroacetate followed by in situ protection and elimination reactions to form the desired vinyl dichlorides in 85 to 95% yields. (C) 2000 Dupont Pharmaceuticals Company.
- Wang, Zhe,Campagna, Silvio,Xu, Guoyou,Pierce, Michael E.,Fortunak, Joseph M.,Confalone, Pat N.
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p. 4007 - 4009
(2007/10/03)
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- Fibrinogen receptor antagonists
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Fibrinogen receptor antagonists having the structure, for example, of STR1 for example STR2
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- In-plane vinylic S(N)2 substitution and intramolecular β elimination of β-alkylvinyl(chloro)-λ3-iodanes
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The reactions of four (E)-β-alkylvinyl(phenyl)iodonium salts with chloride ion were examined in acetonitrile and in several other solvents at 25°C. The β-methyl-, β-octyl-, and β-isopropyl-substituted iodonium salts undergo competitive bimolecular nucleophilic substitution to form the corresponding (Z)-1-chloro-1-alkene with inversion of configuration at the vinylic carbon and elimination to form the 1-alkyne. The β-tert-butyl-substituted iodonium salt affords only the products of the elimination reaction. The UV absorption spectra of the reactants show the rapid coversion of chloride and iodonium ions to an equilibrium mixture of the corresponding chloro-λ3-iodane, with an association constant of 5600-7600 mol-1 dm3. A kinetic analysis shows that most of the substitution and elimination products form from reaction of the λ3-iodane. Evidence is presented that the substitution reaction proceeds by a concerted bimolecular S(N)2 mechanism and that the elimination reaction proceeds by a unimolecular reaction mechanism with intramolecular transfer of the β-proton to the leaving group.
- Okuyama, Tadashi,Takino, Tomoki,Sato, Koichi,Ochiai, Masahito
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p. 2275 - 2282
(2007/10/03)
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- Sigmatropic Ring Expansion of Cyclic Thionocarbonates. 13. Synthesis of Medium-Membered Heterocyclic Allenes and Synthetic Application to Antifungal Constituent of Sapium Japonicum
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Cyclic allenes (3a-k, 3n) containing a SCOO moiety in the range of 8- to 11-membered ring were synthesized by the sigmatropic rearrangement of the alkynyl cyclic thionocarbonates (2).Ring expansion of 6-membered cyclic thionocarbonates (2i-k) afforded a new type of strained 8-membered heterocyclic allenes (3i-k) in high yields.The MNDO optimized structure of 3i indicated the allenyl moiety was bent and strained.The reactivity of 8-membered cyclic allenes was also examined.Further, using this methodology with a novel application of a SmI2-HMPA reduction of resulting heterocyclic allene (3n), an antifungal constituent of a Sapium japonicum, (+/-)-methyl 8-hydroxy-5,6-octadienoate (24), was synthesized.
- Harusawa, Shinya,Moriyama, Hideki,Kase, Naoki,Ohishi, Hirofumi,Yoneda, Ryuji,Kurihara, Takushi
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p. 6475 - 6494
(2007/10/02)
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- Flash Vacuum Pyrolysis of Stabilised Phosphorus Ylides. Part 1. Preparation of Aliphatic and Therminal Alkynes
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Thermal extrusion of Ph3PO from β-oxoalkylidenetriphenylphosphoranes 4 to give the alkynes 5, which under conventional pyrolysis conditions is restricted to cases in which R1 is an electron withdrawing group, has been successfully achieved for R1=H or alkyl by using FVP.The method allows convenient construction of multigram quantities of the alkynes 5 from alkyl halides 1 and allows convenient construction of multigram quantities of the alkynes 5 from alkyl halides 1 and acid chlorides 3 in three steps with good overall yields.Under the conditions used the ylides with R2 = cyclobutyl also undergo less of ethene to provide convenient access to the vinylalkynes 6.
- Aitken, R. Alan,Atherton, J. Ian
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p. 1281 - 1284
(2007/10/02)
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- Convenient Procedures for t-Butylacetylene and Vinylacetylene
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Treatment of the dichlorides t-C4H9CH2CHCl2 and E-ClCH2CH=CHCH2Cl with a suspension of powdered potassium hydroxide in high-boiling petroleum at elevated temperatures in the presence of Aliquat-336 and pinacol gives t-butylacetylene and vinylacetylene in high yields.Vinylacetylene is also obtainable by treating E-ClCH2CH=CHCH2Cl with a concentrated aqueous solution of KOH in the presence of Aliquat-336.
- Verkruijsse, H.D.,Brandsma, L.
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p. 3355 - 3358
(2007/10/02)
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- A METHOD FOR THE PREPARATION OF TERMINAL ACETYLENES
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A new pathway is proposed for the preparation of terminal acetylenes entailing the condensation of acid chlorides with phenylacetylene, isomerization of the acetylenic ketones with displacement of the oxo group and triple bond in the ketoacetylenic fragment, and subsequent alkaline cleavage of the isomerized ketones.
- Fedenok, L. G.,Shvartsberg, M. S.
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p. 2376 - 2377
(2007/10/02)
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- The Reaction Mechanism of Ruthenium-catalyzed Dimerization of t-Butylacetylene to cis-1,4-Di-t-butylbutatriene. Involvement of a Ruthenium-diacetylide Intermediate
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The acetylide complex t)(CO)(PPh3)3> (1) prepared from (2) and Li-CC-But has been found to be a good precursor for the catalytic dimerization of t-butylacetylene to cis-1,4-di-t-butyl-1,2,3-butatriene.Room temperature reaction of 1 with HCCBut has afforded a new complex which has been structurally characterized as possessing cis-diacetylide ligands.Reaction of 2 with 1,4-di-t-butylbutadiyne gave a complex with 1,4-di-t-butylbut-1-en-3-yn-2-yl ligand, t)CCBut>Cl(CO)(PPh3)2>, which decomposed at 60 deg C to liberate cis-1,4-di-t-butyl butatriene.The reaction mechanism is discussed based on the findings.
- Wakatsuki, Yasuo,Satoh, Masaaki,Yamazaki, Hiroshi
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p. 1585 - 1588
(2007/10/02)
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- Rates of Base-Catalyzed Hydrogen Exchange of Terminal Acetylenes in Aqueous Solution. Absence of Resonance Interaction
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Rates of detritiation of 13 monosubstituted acetylenes labeled at the acetylenic hydrogen position were measured in aqueous amine buffer solution at 25 deg C, and hydroxide ion catalytic coefficients were evaluated.These rate constants, plus a few additional values from the literature, give a good correlation against inductive or field substituent constants: log(kHO-/M-1s-1) = 1.46+/-0.12 + (8.00+/-0.50)?I.This correlation is not improved by addition of resonance substituted constants, and the coefficients of the resonance term in two different dual parameter (resonance plus field) treatments of the data are in fact zero.
- Kresge, A. J.,Powell, M. F.
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p. 819 - 822
(2007/10/02)
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- DIOLS AS EFFECTIVE COCATALYSTS IN THE PHASE TRANSFER CATALYZED PREPARATION OF 1-ALKYNES FROM 1,2-DIHALIDES
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Bis-tertiary diols accelerate bis-eliminations of HX from 1,2-dihalides in the presence of an onium salt as phase transfer catalyst and potassium hydroxyde as base.PEG 400 catalyzes the same elimination, but isomerizations from 1-alkyne to mixtures with the 2-alkyne and the 1,2-diene occur easily.
- Dehmlow, Eckehard V.,Thieser, Rainer,Sasson, Yoel,Neumann, Ronny
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p. 3569 - 3574
(2007/10/02)
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- A New General Synthesis of Aliphatic and Terminal Alkynes: Flash Vacuum Pyrolysis of β-Oxoalkylidenetriphenylphosphoranes
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By using flash vacuum conditions the thermal elimination of Ph3PO from β-oxoalkylidenetriphenylphosphoranes, previously confined to cases with an α-electron withdrawing group, has been extended to provide a general, high yielding synthesis of aliphatic and terminal alkynes.
- Aitken, R. Alan,Atherton, J. Ian
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p. 1140 - 1141
(2007/10/02)
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- THE ELECTRON SPIN RESONANCE SPECTRA OF THE ANNULENE (CYCLOBUTADIENE) RADICAL CATIONS, R4C4+.
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A series of simple (R=R') and mixed (RR') cyclobutadiene radical cations, R2R'2C4+., have been prepared by photolysis of the alkynes, RCCR' or of mixtures of the alkynes RCCR and R'CCR', in dichloromethane in the presence of aluminium chloride, and the e.s.r. spectra have been recorded.The magnitude of the 13C hyperfine coupling in Et4C4+. confirms that it is a ?-radical, with no evidence for out-of-plane or in-plane (Jahn-Teller) distortion.The values of a(Hβ) for the radicals (RCH2)4C4+. and (RCH2)2R'2C4+. indicate that, as the bulk of the alkyl substituents increases, the group R is pushed out of the plane of the ring.Some unusual temperature effects on a(Hβ) are ascribed to interaction of the radical cation with the solvent or with the counterion.As the bulk of the alkyl groups increases, the g-value decreases from 2.0030 to about 2.0022. cis- and trans-Isomers of the radicals Me2tBu2C4+., Et2tBu2C4+., iBu2tBu2C4+., and propably Me2Et2C4+. have been identified, and the spectra of cis- and trans-Me2tBu2C+. are analysed in terms of breaking of the degeneracy of the molecular orbitals of the cyclobutadiene system by differential electron release by the alkyl groups (tBu > Me).
- Courtneidge, John L.,Davies, Alwyn G.,Lusztyk, Ewa,Lusztyk, Janusz
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p. 155 - 164
(2007/10/02)
-
- Organolanthanoids. III Preparations and Properties of Some Di(alkynyl)lanthanoids
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From reactions between di(alkynyl)mercurials and lanthanoid elements in tetrahydrofuran or 1,2-dimethoxyethane, the organolanthanoids (PhCC)2Yb and (PhCC)2Eu(thf)0.25 (thf = tetrahydrofuran) have been isolated, and (RCC)2M (R = Ph or But, M = Yb; R = Ph, M = Eu) characterized in solution.Bis(phenylethynyl)ytterbium has aslo been obtained by ligand exchange between (C6F5)2Yb or (ButCC)2Yb and phenylacetylene.The di(alkynyl)lanthanoids are considered to have associated structures with bridging alkynyl groups.Hydrolysis of (RCC)2M derivatives yields acetylenes RCCH, together with alkenes RCHCH2 (greater for M = Yb than M = Eu), and, when M = Yb, R = Ph, a little ethylbenzene.
- Deacon, Glen B.,Koplick, Andrew J.,Tuong, Tran D.
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p. 941 - 949
(2007/10/02)
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- Alkyne Formation in the Reaction of α-Bromo Ketones with Arylsulfonylhydrazines
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Alkynes can be produced by treating some α-bromo ketones with arylsulfonylhydrazines.The reaction is acid-catalysed and mesitylsulfonylhydrazine was the most efficient hydrazine reagent examined.The mechanism of the reaction has not been elucidated although it is shown not to proceed via an α-bromo mesitylsulfonylhydrazone.
- Bryant, Michael W.,Smith, Robin A. J.,Wong, Lisa
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p. 2529 - 2540
(2007/10/02)
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- A CONVENIENT ROUTE TO ALKYNES VIA PHASE TRANSFER CATALYSIS; ( APPLICATIONS OF PHASE TRANSFER CATALYSIS, PART 19 )
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High yield, rapid formations of alkynes from vic-dibromides are possible using powered potassium hydroxide and catalytic amounts of lipophilic phase transfer catalysts.Reasons are given why molar amounts of expensive catalysts were necessary in earlier procedures.
- Dehmlow, Eckehard V.,Lissel, Manfred
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p. 1653 - 1658
(2007/10/02)
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- Synthesis, Stereochemistry, and Crystal and Molecular Structure of 4-Bromo-1,2,2,3-tetramethyl-1-phenylphosphetanium Bromide
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The synthesis of 4-bromo-2,2,3-trimethyl-1-phenylphosphetan 1-oxide was achieved by reaction of 1-bromo-3,3-dimethylbut-1-ene with phenylphosphonous dichloride in the presence of anhydrous aluminium chloride, followed by the addition of water.The oxide was converted into the title compound by reduction (Cl3SiH) and then quaternization with methyl bromide.The title compound crystallizes in the monoclinic space group P21/n, with four molecules in the unit cell of dimensions a = 7.653(1), b = 12.662(3), c = 15.487(3) Angstroem and β = 97.58(2) deg.The structure was solved by the heavy-atom method and refined to a final R value of 0.065.The four-membered ring is puckered with a dihedral angle of 34.0 deg.The methyl substituent at C(3) and the phenyl group have a cis-relation, whereas the bromo-substituent and phenyl ring are trans.All three of these groups occupy eqatorial positions with respect to the ring.
- Mazhar-ul-Haque,Horne, William,Cremer, Sheldon E.,Kremer, Paul W.,Kafarski, Pawel K.
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p. 1138 - 1142
(2007/10/02)
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- Small Rings, 27. - Attempts to Synthesize Azacyclobutadienes
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Photolysis of oxazinones 5 at low temperature yields the bicyclic valence isomers 8 and the ringopened ketenes 4 which can be characterized spectroscopically.Photoelimination of CO2 from bicyclus 8d gives azacyclobutadiene (azete) 2d, as indicated by the fragmentation pattern.The results of matrix irradiation of cyclopropenyl azides, 1,2,3- and 1,2,4-triazines also prove that azacyclobutadienes undergo ready cleavage into the corresponding nitriles and acetylenes.
- Maier, Guenther,Schaefer, Ulrich
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p. 798 - 813
(2007/10/02)
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- Application of Phase Transfer Catalysis, 14.- Preparation of Alkynes from Halides with Solid Potassium tert-Butoxide and Crown Ether
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Preparatively very simple and mild HX eliminations with solid potassium tert-butoxide in petroleum ether in the presence of catalytic amounts of crown-6 are described. 1,2-Dihalides (from alkenes) and 1,1-dihalides (from aldehydes) yield 1-alkynes; internal geminal dihalides (from symmetric ketones) give internal alkynes in excellent yields. 2,2-Dihalides (from methyl ketones) yield homogeneous 1-alkynes only if the 3-position is blocked. (E)-Haloalkenes lead also to alkynes in a syn-elimination process.
- Dehmlow, Eckehard V.,Lissel, Manfred
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