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Phenylacetylen

CONDENSATIONS WITH SODAMIDE IN LIQUID AMMONIA Acetylenic compounds are conveniently prepared with the aid of Uquid ammcx as a solvent. The preparation of a simple acetylenic hydrocarbon ( -butylacetylene or 1-hexyne) and also of phenylacetylene is described. Experimental details are also given for two acetylenic carbinols, viz., 1-ethynyl-eyciohoxanul and 4-pentyn-l-ol. It will be noted that the scale is somewhat laige smaller quantities can readily be prepared by obvious modifications of the directions. [Pg.895]

Phenylacetylene is readily prepared by the dehydrohalogenatlon of styrene dibromide with a solution of sodamide in liquid ammonia ... [Pg.896]

Phenylacetylene. Support a 5-litre glass Dewar flask in a wooden case. Equip the flask with a lid of clear Perspex, provided with suitable apertures for a mechanical stirrer, introducing solids (e.g., sodium) or hquids, a calibrated dip stick for measuring the volume of liquid in the Dewar vessel, a gas mlet tube and an ammonia inlet arrange for an electric light to shine downwards into the flask. [Pg.900]

As an application of maleate formation, the carbonylation of silylated 3-butyn-l-ol affords the 7-butyrolactone 539[482], Oxidative carbonylation is possible via mercuration of alkynes and subsequent Lransmetallation with Pd(II) under a CO atmosphere. For example, chloromercuration of propargyl alcohol and treatment with PdCF (1 equiv.) under 1 atm of CO in THF produced the /3-chlorobutenolide 540 in 96% yield[483]. Dimethyl phenylinale-ate is obtained by the reaction of phenylacetylene, CO, PdCU, and HgCl2 in MeOH[484,485]. [Pg.100]

Many examples of insertions of internal alkynes are known. Internal alkynes react with aryl halides in the presence of formate to afford the trisubstituted alkenes[271,272]. In the reaction of the terminal alkyne 388 with two molecules of iodobenzene. the first step is the formation of the phenylacetylene 389. Then the internal alkyne bond, thus produced, inserts into the phenyl-Pd bond to give 390. Finally, hydrogenolysis with formic acid yields the trisubstituted alkene 391(273,274], This sequence of reactions is a good preparative method for trisubstituted alkenes from terminal alkynes. [Pg.181]

The carbonylation of aryl iodides in the presence of terminal alkynes affords the acyl alkynes 565. Bidentate ligands such as dppf give good results. When PhjP is used, phenylacetylene is converted into diphenylacetylene as a main product[4l5]. Triflates react similarly to give the alkynyl ketones 566[4I6], In... [Pg.205]

J-unsaturated ester is formed from a terminal alkyne by the reaction of alkyl formate and oxalate. The linear a, /J-unsaturated ester 5 is obtained from the terminal alkyne using dppb as a ligand by the reaction of alkyl formate under CO pressure. On the other hand, a branehed ester, t-butyl atropate (6), is obtained exclusively by the carbonylation of phenylacetylene in t-BuOH even by using dppb[10]. Reaction of alkynes and oxalate under CO pressure also gives linear a, /J-unsaturated esters 7 and dialkynes. The use of dppb is essen-tial[l 1]. Carbonylation of 1-octyne in the presence of oxalic acid or formic acid using PhiP-dppb (2 I) and Pd on carbon affords the branched q, /J-unsatu-rated acid 8 as the main product. Formic acid is regarded as a source of H and OH in the carboxylic acids[l2]. [Pg.473]

Tandem cyclization/3-substitution can be achieved starting with o-(trifluoro-acetamido)phenylacetylenes. Cyclization and coupling with cycloalkenyl trif-lates can be done with Pd(PPh3)4 as the catalyst[9]. The Pd presumably cycles between the (0) and (II) oxidation levels by oxidative addition with the triflate and the reductive elimination which completes the 3-alkenylation. The N-protecting group is removed by solvolysis under the reaction conditions, 3-Aryl groups can also be introduced using aryl iodides[9]. [Pg.23]

Tandem cyclization and 3-carboxylation has been done with o-(methanesulf-onamido)phenylacetylenes by conducting the reaction in methanol under a CO atmosphere[10]. [Pg.23]

Styrene undergoes many reactions of an unsaturated compound, such as addition, and of an aromatic compound, such as substitution (2,8). It reacts with various oxidising agents to form styrene oxide, ben2aldehyde, benzoic acid, and other oxygenated compounds. It reacts with benzene on an acidic catalyst to form diphenylethane. Further dehydrogenation of styrene to phenylacetylene is unfavorable even at the high temperature of 600°C, but a concentration of about 50 ppm of phenylacetylene is usually seen in the commercial styrene product. [Pg.477]

Solutions of RC triple-bond C—Ti(0-/-C2H2)2 can be prepared by treating acetylenic compounds, such as phenylacetylene, with butyl lithium and then Cl—Ti(0-/-C2H2)2. These materials can react with aldehydes and epoxides to give the expected addition products (215). [Pg.155]

Class (2) reactions are performed in the presence of dilute to concentrated aqueous sodium hydroxide, powdered potassium hydroxide, or, at elevated temperatures, soHd potassium carbonate, depending on the acidity of the substrate. Alkylations are possible in the presence of concentrated NaOH and a PT catalyst for substrates with conventional pX values up to - 23. This includes many C—H acidic compounds such as fiuorene, phenylacetylene, simple ketones, phenylacetonittile. Furthermore, alkylations of N—H, O—H, S—H, and P—H bonds, and ambident anions are weU known. Other basic phase-transfer reactions are hydrolyses, saponifications, isomerizations, H/D exchange, Michael-type additions, aldol, Darzens, and similar... [Pg.186]

Another appHcation for this type catalyst is ia the purification of styrene. Trace amounts (200—300 ppmw) of phenylacetylene can inhibit styrene polymerization and caimot easily be removed from styrene produced by dehydrogenation of ethylbenzene using the high activity catalysts introduced in the 1980s. Treatment of styrene with hydrogen over an inhibited supported palladium catalyst in a small post reactor lowers phenylacetylene concentrations to a tolerable level of <50 ppmw without significant loss of styrene. [Pg.200]

The direct combination of selenium and acetylene provides the most convenient source of selenophene (76JHC1319). Lesser amounts of many other compounds are formed concurrently and include 2- and 3-alkylselenophenes, benzo[6]selenophene and isomeric selenoloselenophenes (76CS(10)159). The commercial availability of thiophene makes comparable reactions of little interest for the obtention of the parent heterocycle in the laboratory. However, the reaction of substituted acetylenes with morpholinyl disulfide is of some synthetic value. The process, which appears to entail the initial formation of thionitroxyl radicals, converts phenylacetylene into a 3 1 mixture of 2,4- and 2,5-diphenylthiophene, methyl propiolate into dimethyl thiophene-2,5-dicarboxylate, and ethyl phenylpropiolate into diethyl 3,4-diphenylthiophene-2,5-dicarboxylate (Scheme 83a) (77TL3413). Dimethyl thiophene-2,4-dicarboxylate is obtained from methyl propiolate by treatment with dimethyl sulfoxide and thionyl chloride (Scheme 83b) (66CB1558). The rhodium carbonyl catalyzed carbonylation of alkynes in alcohols provides 5-alkoxy-2(5//)-furanones (Scheme 83c) (81CL993). The inclusion of ethylene provides 5-ethyl-2(5//)-furanones instead (82NKK242). The nickel acetate catalyzed addition of r-butyl isocyanide to alkynes provides access to 2-aminopyrroles (Scheme 83d) (70S593). [Pg.135]

The thermal or photolytic fragmentation of furazans to nitriles and nitrile Af-oxides has been reported (73JOC1054, 75JOC2880). The irradiation of dimethylfurazan (419) in the presence of cyclopentene, and benzofurazan (420) in the presence of dimethyl acety-lenedicarboxylate, gave isoxazoline (421) and isoxazole (422), respectively, in good yields. The thermolysis of acenaphtho[l,2-c]furazan (423) in the presence of phenylacetylene gave isoxazole (424) in 55% yield. [Pg.81]

The rates of bromination of a number of alkynes have been measured under conditions that permit comparison with the corresponding alkenes. The rate of bromina-hon of styrene exceeds that of phenylacetylene by about For internal alkyne-... [Pg.375]


See other pages where Phenylacetylen is mentioned: [Pg.242]    [Pg.895]    [Pg.896]    [Pg.900]    [Pg.900]    [Pg.900]    [Pg.901]    [Pg.227]    [Pg.206]    [Pg.484]    [Pg.572]    [Pg.606]    [Pg.974]    [Pg.481]    [Pg.488]    [Pg.118]    [Pg.233]    [Pg.68]    [Pg.83]    [Pg.84]    [Pg.157]    [Pg.122]    [Pg.123]    [Pg.275]    [Pg.828]    [Pg.891]    [Pg.147]    [Pg.327]    [Pg.492]    [Pg.31]   
See also in sourсe #XX -- [ Pg.93 ]




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1- Bromo-2-phenylacetylene

3-Hexyne phenylacetylene

4-Methyl-phenylacetylene

4-Methyl-phenylacetylene cation

Acetophenone oxime, reaction with phenylacetylene

Acetylene copolymers with phenylacetylene

Addition phenylacetylene

Bromination of phenylacetylene

Bromine, reaction with phenylacetylene

Carbonylative phenylacetylene

Convergent synthesis, phenylacetylene

Convergent synthesis, phenylacetylene dendrimers

Cupric acetate in coupling of phenylacetylene

Cyano-2-phenylacetylene

Cyclotrimerization of phenylacetylene

Dendrimers phenylacetylene-based

Dimerization phenylacetylene

Ethylbenzene phenylacetylene

Hydration of phenylacetylene

Hydroamination reactions phenylacetylene with

Hydrogenation of phenylacetylene

Hydrosilylation of phenylacetylenes

INDEX phenylacetylene

Infrared spectrum, benzaldehyde phenylacetylene

Kinetics Phenylacetylene

L-chloro-2-phenylacetylene

Lithium-phenylacetylene adducts

Macrocycles phenylacetylene

Molecular systems phenylacetylene

Nickelacyclopentenediones via phenylacetylenes

Nitro phenylacetylene

Oxidative coupling, phenylacetylene

Oxidative coupling, phenylacetylene acetate

Oxidative coupling, phenylacetylene diphenyldiacetylene with cupric

Para-substituted phenylacetylenes

Phenols phenylacetylene

Phenylacetylene

Phenylacetylene

Phenylacetylene Phenylalanine

Phenylacetylene acetylenes

Phenylacetylene alkenylation with

Phenylacetylene alkylation

Phenylacetylene amination

Phenylacetylene anionic polymerization

Phenylacetylene asymmetric addition

Phenylacetylene azide

Phenylacetylene carbonylation

Phenylacetylene cross-coupling

Phenylacetylene cyclotrimerization

Phenylacetylene dendrimer

Phenylacetylene dendrimers

Phenylacetylene deprotonation

Phenylacetylene dimer

Phenylacetylene ester

Phenylacetylene ethylmagnesium bromide

Phenylacetylene hydrogen bonding

Phenylacetylene hydrophosphination

Phenylacetylene hydrosilylation

Phenylacetylene macrocycle

Phenylacetylene macrocycles, synthesis

Phenylacetylene macrocyclizations

Phenylacetylene macromolecules

Phenylacetylene metathesis polymerization

Phenylacetylene metathesis polymerization mechanism

Phenylacetylene monodendrons

Phenylacetylene monomers

Phenylacetylene oligomer

Phenylacetylene oligomers

Phenylacetylene oxidation

Phenylacetylene photohydration

Phenylacetylene polymerisation

Phenylacetylene preparation

Phenylacetylene propiolate complexes

Phenylacetylene radical cation

Phenylacetylene reaction with Grignard reagents

Phenylacetylene sequences

Phenylacetylene thermal polymerization

Phenylacetylene transition metal complexes

Phenylacetylene unsymmetrical

Phenylacetylene with OsHCl

Phenylacetylene, acidity

Phenylacetylene, hydration

Phenylacetylene, hydrosilation

Phenylacetylene, oxidative coupling diphenyldiacetylene

Phenylacetylene, oxidative coupling palladium catalyst

Phenylacetylene, oxidative coupling partial reduction to styrene using

Phenylacetylene, oxidative coupling reaction with sodium hypobromite

Phenylacetylene, polymerization

Phenylacetylene, reaction with

Phenylacetylene, reaction with ethyl

Phenylacetylene, reaction with ethyl chloride

Phenylacetylene, reaction with ethyl magnesium bromide

Phenylacetylene, reaction with iodonium

Phenylacetylene, reaction with ruthenium

Phenylacetylene, reaction with ruthenium complexes

Phenylacetylene, reactions

Phenylacetylene, reduction

Phenylacetylene, synthesis

Phenylacetylene-containing dendrimers

Phenylacetylene/norbornene

Phenylacetylene: Benzene, ethynyl

Phenylacetylenes

Phenylacetylenes acetate

Phenylacetylenes basicities

Phenylacetylenes hydration

Phenylacetylenes reaction

Phenylacetylenes, hydrosilylation

Phenylacetylenes, substituted

Phenylacetylenes, substituted metathesis polymerization

Phenylacetylenes, trimerization

Poly (phenylacetylenes)

Poly(phenylacetylene)

Polymerization of phenylacetylene

Procedures for solid-supported phenylacetylene chemistry

Reactants phenylacetylene

SOLID-PHASE SYNTHESIS OF SEQUENCE-SPECIFIC PHENYLACETYLENE OLIGOMERS

Sequence-specific phenylacetylene oligomers

Silver nitrate, complexing with phenylacetylene

Sonogashira coupling reactions phenylacetylene

Sonogashira coupling reactions with phenylacetylene

Styrene phenylacetylene

Tandem bimolecular coupling followed by intramolecular cyclization to form a foldable phenylacetylene macrotetracycle

The Annulenes, Dehydrobenzoannulenes, and Phenylacetylene Scaffolding

Triethylsilanes, phenylacetylene hydrosilylations

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