Methyl phenyl acetylene

Methyl phenyl acetylene Ethanol Ethyl a-methylcinnamate [457]... 

Scheme 14.13 Proposed mechanism for the hydrogenation of phenyl acetylene by [Pd(methyl 2-pyridyl ketone thiosemicarba-zonato)Cl] (29a).

Figure 4 in Scheme 2.3-4 demonstrates that when using a triphenylphosphane-modified Ni-catalyst, butadiene reacts with 2-butyne to form a 2 1-adduct whereas with methyl 2-butynoate, a 1 2 co-oligomer is obtained. Butadiene and phenyl-acetylene also form 1 2 products As we may have shown, a change from X- to C- or Z-type substituents in the co-substrates alters the ratio from 2 1 to 1 2 in a synthon coupling reaction. 

Die direkte, reduktive Aminierung einer acetylenischen Gruppe gelingt bei 2-Ethinyl-pyri-dinen durch Erhitzen mit Methylamin-Hydrochlorid und Natrium-cyanoboranat in Ethanol2. So erhalt man z. B. aus 2-Ethinyl-6-methyl-pyridin bei einer Reaktionszeit von 24 h 2-(2-Dimethylammo-ethyl)-6-methyl-pyridin in 76% Ausbeute. Mit Phenylacetylen gelingt die Reaktion nicht aus (4-Nitro-phenyl)-acetylen und Methylamin-Hydrochlorid erhalt man dagegen in glatter Reaktion l-Methylamino-2-(4-nitro-phenyl)-ethan. 

By the extension of the above-mentioned stereoselective asymmetric addition of alkylithiums to other organolithium reagents such as lithium salts of methyl phenyl sulfide, 2-methylthiazoline, trialkylsilylacetylene, N-nitroso-dimethylamine, and acetonitrile, chiral oxiranes (95) U1), thiiranes (96) nl), acetylenic alcohols (98) 112), and amino alcohols (97) U1) were readily obtained. 

Olefins, e.g., ethylene or styrene, do not displace the hydroxyacetylene from these complexes. The stability of the complexes depends on the group R. of the acetylene RMeC(OH)-C. C-C(OH)Me2 it decreases in the order R = methyl > phenyl > hydrogen. Methylation of the hydroxyl groups also lowers the stability of the complexes 36). 

Benzo[6]thiophene is formed when thiophenol reacts with acetylene in a heated iron tube 230 or with either ethylene281 or acetylene232 233 in the presence of a heated catalyst. Likewise, with acetylene, methyl phenyl sulfide (thioanisole) affords benzo[6]thiophene, while both p-thiocresol and di(p-tolyl) sulfide afford 5-methylbenzo[6]thio-phene.230... 

Over the last few years it has become clear that rhodium(II) acetate is more effective than the copper catalysts in generating cyclopropenes.12 126 As shown in Scheme 28,12S a range of functionality, including terminal alkynes, can be tolerated in the reaction with methyl diazoacetate. Reactions with phenyl-acetylene and ethoxyacetylene were unsuccessful, however, because the alkyne polymerized under the reaction conditions. 

Pyrolysis of poly(methylacetylene) shows rather similar behaviour 528>, with mesi-tylene as the major product but substantial yields of methyl and proton-enriched products. Thermal decomposition of this polymer sets in at around 150 °C and the mechanism is postulated to involve chain scission followed by cyclization reactions and both electron-proton and electron-methyl exchanges. Pyrolysis of poly(phenyl-acetylene) has been reported to start at 270 °C in nitrogen 529). 

Papain, 340 Penicillin, 158 Perhydrohistrionicotoxin, 306 Phenyl acetylene, 292, 293 2-Phenyl-N-methyl-5,6-dihydro-l,3-thiazinium tetrafluoroborates, 146... 

Our kinetic work (10) showed that the small molecule radical produced by chain transfer with monomer had to be a stable radical. This was confirmed in the present paper by analysis of the isotope effect on the bulk polymerization rates. The isotope effect on molecular weights and rates unequivocally showed that almost 100% of the chain transfer involved the vinyl hydrogen. There is some evidence in the literature to support the idea of a stable vinyl radical. Phenyl acetylene acts as a retarder when copolymerized with styrene or methyl methacrylate (25). Thus the phenyl vinyl radical is very stable compared to the growing styryl or methacrylyl radical. 

Other unsaturated substrates arylated by various diaryl iodonium salts included butenone, acrylic acid, methyl acrylate and acrylonitrile [46]. Allyl alcohols with diaryliodonium bromides and palladium catalysis were arylated with concomitant oxidation for example, from oc-methylallyl alcohol, aldehydes of the general formula ArCH2CH(Me)CHO were formed [47]. Copper acetylide [48] and phenyl-acetylene [49] were also arylated, with palladium catalysis. 

V. Heterocyclic ring closure of o-hydroxylated aromatic compounds with acetylenic side chains. This method leads from acetylenic compounds 221 to 2-substituted benzofurans 222. Thus, l-(2-hydroxy-5-methyl)phenyl-2-phenylacetylene (221a), heated at 90° for 45 minutes in the presence of 2 iV NaOH, gives 5-methyl-2-phenylbenzofuran (222a) (90% yield). 

Yamanaka and co-workers ° prepared 2-methyl-5-phenyl-4-(phenylethynyl)ox-azole 972 and 2-methyl-4-phenyl-5-(phenylethynyl)oxazole 974 in excellent yield via palladium-catalyzed coupling of the bromooxazoles 971 and 973 with phenyl-acetylene (Scheme 1.261). In contrast, the products derived from coupling with trimethylsUylacetylene decomposed during purification. 

Hydrogenation of fluoromethyl-acetylene derivative of methyl phenyl sulfone Pd/CaCOj Florfenicol MASR... 

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