Methyl phenylethynyl

Methyl phenylethynyl telluride (typical procedure). To NaNH2 (from 6.0 g, 0.26 mol Na) in liquid NHj (250 mL) is added phenylacetylene (25 g, 0.25 mol) dropwise, and then Te powder (30 g, 0.24 mol) in small portions, stirring well for 30 min. Methyl iodide (36 g, 0.25 mol) is added over 20 min to the tellurolate solution. The NHj is then evaporated, the residue extracted with ether and the ether solntion washed with HjO and dried (MgS04). The residue is distilled under vacnum, giving the product (28 g (46%) b.p. 122-124°C/2 torr). 

Methyl Phenylethynyl Tellurium1 An apparatus suitable for work with liquid ammonia is set up. Sodium amide is prepared in a 1 -l flask by adding 6.0 g (0.26 mol) of sodium to 250 ml of liquid ammonia, than 25 g (0.25 mol) of phenylacetylene are added dropwise. 30 g (0.24 mol) of tellurium powder are added over 20 min in small portions to the well-stirred sodium amide solution. 36 g (0.25 mol) of methyl iodide are added dropwise over 10 min to the tellurolate solution. The ammonia is then evaporated, the residue is extracted with diethyl ether, the extract is washed with water and the organic phase dried with anhydrous magnesium sulfate. The ether is distilled off and the residue fractionally distilleed under vacuum yield 28 g (48%) b.p. 122-12472 torr (0,267 kPa). 

Although the first alkynylselenonium salt, ethylmethylphenylethynyl sele-nonium picrate,was prepared as early as 1965 [10], it is only very recently that the first reactions of selenonium salts have been reported [11]. Among these salts, acyclic dimethyl(phenylethynyl)selenonium tetrafluoroborate (9) was prepared by methylation of methyl phenylethynyl selenide (10) with Meer-wein s reagent. The acyclic derivative 11 and the cyclic analogue 12 were synthesized by treatment of trimethyl(phenylethynyl)silane (13) and triflu-oromethanesulfonic anhydride with diphenyl selenoxide (14) and dibenzose-lenophene 5-oxide (15), respectively (Scheme 2). 

Intramolecular addition of the amide group to the triple bond in pyrazoles is more difficult, and results in closure of the 5-lactam rather than the y-lactam ring. The reaction time of the 4-phenylethynylpyrazole-3-carboxylic acid amide under the same conditions is extended to 42 h (Scheme 129) (Table XXVII). The cyclization of l-methyl-4-phenylethynyl-l//-pyrazole-3-carboxylic acid amide, in which the acetylene substituent is located in the 7r-electron-rich position of the heterocycle, is the only one complete after 107 h (Scheme 130) (90IZV2089). 

MPEP (2-methyl-6-(phenylethynyl) pyridine) is the best characterized mGlu5 selective non-competitive antagonist. This compound was one of the first of the... 

In contrast to the stabilizing ability of the 2-thienyl substituent, these cations (284+, 292+, and 30+) were less stable than the corresponding polycations connected via the phenylethynyl spacers. All cationic units up to tetracations were similarly reduced in one step upon CV. In these cases, the presumed redox interaction among the cationic units was also small. The first reduction potentials of 284+, 292+, and 30+ were slightly less negative as compared to those of polycations connected via phenylethynyl spacers. This indicates that electrochemical destabilization of the methyl cations by thienyl substituents is similar to the results based on the p/ R+ values. 

A similar approach to modifying Au-surfaces was reported by Grubbs et al, who used the more rigid tether molecule 4-(4-(norborn-5-ene-2-ylmethylenoxy)phenylethynyl)tolane-4 -thiol, shown in Fig. 2. N-Methyl-7-oxanorborn-5-ene-5,6-dicarbimide and 2,3-bis(tert-butoxydimethylsilyloxy-methylene)-norborn-5-ene were used in a grafting-from approach [31]. 

Holm determined the enthalpies of formation of a collection of hydrocarbyhnagnesium bromides by reaction calorimetry with HBr in diethyl ether . He also determined the enthalpies of formation in ethereal solution of the magnesium bromide salts of 20 Bronsted acids, HB, by measuring the enthalpies of reaction of the acid with pentylmag-nesium bromide. For those species that were reported in both studies (hydrocarbyl = phenylethynyl, phenyl, methyl, cyclopropyl, cyclopentyl, cyclohexyl), the enthalpies of formation were identical. The values are listed in Tables 3 and 4. 

Limited theoretical studies (31, 89) on the electron-deficient beryllium derivatives have been interpreted to imply that extensive Be—Be bonding occurs. If such bonding does occur, the increased bond length observed in the phenylethynyl(methyl)beryllium trimethylamine adduct takes on additional significance since the Be—Be distance in this derivative is increased by almost 0.3 A over that observed in dimethyl-and diethylberyllium. Moreover, if cyclic trimers are formed, then increased metal-metal distances would be likely, thus reducing the probability of stabilization of the bridged system by Be—Be bonding. Additional studies will be required both on structures and of spectroscopic properties of the species to answer these questions. 

The method has been applied by the submitters2 to the preparation of cyclohexylmethylpropiolaldehyde diethyl acetal (54% yield) from cyclohexylmethylacetylene and triethyl orthoformate of phenylethynyl n-butyl dimethyl ketal (40% yield) from phenylacetylene and trimethyl -orthovalerate and of phenylethynyl methyl diethyl ketal (34% yield) from phenylacetylene and triethyl orthoacetate. w-B utylpropiolaldehyde diethyl acetal was isolated in 32% yield by heating an equimolar mixture of 1-hexyne and triethyl orthoformate containing catalytic amounts of a zinc chloride-zinc iodide catalyst under autogenous pressure at 190° for 3 hours. 

A factor that affects the kinetics of the polymerization, and, more critically, the utility of the monomer in copolymerizations with other monomers, e.g., methyl methacrylate, is the stability of the radical formed from addition of the growing polymer chain to the vinyl terminus. In order to gauge the stabilizing effect of the phenylethynyl group, and the sensitivity of the stabilization to substitution at the para position of the aromatic ring, Ochiai and co-workers carried out calculations at the UHF/3-21G level to evaluate (i) the spin density in the 1-phenylprop- l-yn-3-yl radical and (ii) the reaction energy for the process... 

MRS1191 3-ethyl-5-benzyl-2-methyl-6-phenyl-4-phenylethynyl-l,4-(+/-)- dihydropyridine-3,5-dicarboxylate... 

MRS 1340 1,4-Dihydro-2-methyl-6-phenyl-4-(phenylethynyl)-3,5-pyr idinedi-carboxyhc acid 3-ethyl-5-[(3-nitrophenyl)methyl] ester... 

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