Methanol triphenyl

Fig. 12-14.—Infrared absorption spectra of methanol, triphenyl-carbinol, carbazole, and aniline in carbon tetrachloride solution (Hilbert, Wulf, Hendricks, and Liddell). Ordinates represent the molal absorption coefficient and abscissas the wave number, in cm 1.

The reduction of benzofuroxans can lead to a variety of products, depending upon the conditions. Deoxygenation to benzofurazans (40) can be effected either directly, using trialkyl phosphites, -tributyl or triphenyl - phosphine, or indirectly, via o-quinone dioximes (41), using methanol and potassium hydroxide, or hydroxyl-amine and alkali. - - The dioximes may be isolated, but... 

Chloro-5,6-diphenyl-as-triazine readily undergoes methoxy-de-chlorination at 25° (< 12 hr) with methanolic methoxide and at 65° (4.5 hr) in non-basified methanol. The chloro group is also displaced by hydrazine (80°, 1 hr), ammonia (140°, 6 hr), and phenyl-magnesium bromide (70°, 12 hr), the latter forming the triphenyl compound 315.3-Chloro-6-phenyl-as-triazine is unstable to cold water or alkali and to hot alcohol or aqueous potassium carbonate. ... 

The Mitsunobu reaction was also applied to the synthesis of [ 1,2,4]triaz-ino[4,5-n]indoles (84AG517). Thus, reaction of the 2-acylindoles 127 with sodium borohydride in methanol or with lithium aluminium hydride in tetrahydrofuran gave the corresponding alcohols 128. Their cyclization with diethyl azodicarboxylate in the presence of triphenyl-phosphine gave the triazinoindoles 129. Acid treatment of the latter afforded 130 (Scheme 30). 

This material may be converted directly to a phosphonium salt 1.40 g. (0.0054 mole) of the crude iodide is dissolved in 20 ml. of benzene, and 1.42 g, (0.0054 mole) of triphenylphosphine [Phosphine, triphenyl-] is added. On standing, 2.5 g. (77%) of the triphenylphosphonium salt precipitates as a colorless 1 1 complex with benzene, m.p. 135-137°. Recrystallization from methanol-benzene raises the melting point to 140-142°. Analysis calculated for C28H29PI CeH6 C, 68.23 H, 5.39. Found C, 68.15 H, 5.28. 

Wahrend 2-Halogen-1-oxo-l-phenyl-alkane mit Triphenyl-phosphan zu (2-Oxo-2-phenyl-athyl)-triphenyl-phosphoniumhalogeniden reagieren, werden sek. und tert.-x -Brom-ketone in siedendem Benzol-Methanol-Gemisch (auch mit Zusatz von Salzsaure) (bestes Verhaltnis 8,4 1) zum Keton enthalogeniert1 ... 

The formation of diphenylphosphino radicals on photolysis of triphenyl-phosphine, diphenylphosphine, and tetraphenylbiphosphine has been verified. In the case of the reactions of the phosphines, the radicals were trapped with t-nitrosobutane and the resultant nitroxyl radical [Ph2PN(0)Bu ] was identified by e.s.r. The nitroxyl radical has a small P splitting constant, demonstrating that there is no extensive delocalization onto the phosphorus atom. The e.s.r. spectrum of diphenylphosphino radicals, generated by photolysis of tetraphenylbiphosphine in benzene at 77 K, has been observed. When methanolic solutions of the biphosphine or triphenylphosphine are flash-photolysed, a transient species having Amax = 330 nm and which decays by first-order kinetics (A 4 x 10 s )... 

Finally, a reaction should be mentioned in which a nucleophile gives support to another reacting species without appearing in the final product. Diphenyl cyclopropenone interacts with 2,6-dimethyl phenyl isocyanide only in the presence of tri-phenylphosphine with expansion of the three-ring to the imine 344 of cyclobutene-dione-1,2229,230 Addition of the isocyanide is preceded by formation of the ketene phosphorane 343, which can be isolated in pure formss 231 it is decomposed by methanol to triphenyl phosphine and the ester 52. 

A mixture of benzylcarbamate (30.6 g, 0.2 mol), paraformaldehyde (6 g, 0.2 mol), acetic anhydride (25.5 g, 0.25 mol), and acetic acid (20 ml) was stirred for 3 h at 60 to 70°C. Triphenyl phosphite (62.1 g, 0.2 mol) was then added, and the mixture was stirred for 2 h at 110 to 120°C. After evaporation of acetic acid and the remaining acetic anhydride under reduced pressure, the residue was dissolved in methanol (150 ml). The mixture was allowed to stand at -10°C for 4 h, after which the precipitate was isolated by suction filtration, washed with methanol, and air-dried. The precipitate was recrystallized from chloro-formtmethanol to give pure diphenyl benzyloxycarbonylami-nomethanephosphonate (38 g, 48%) of mp 114 to 116°C, which exhibited IR and NMR spectra and analyses in accord with the proposed structure. 

To a solution of triphenyl phosphite (6.2 g, 0.02 mol) and thiomethoxy-acetaldehyde (2.25 g, 0.025 mol) in glacial acetic acid (18 ml), powdered N-phenylthiourea was added in a single portion. The reaction mixture was stirred at room temperature for 30 min and then for 30 min at 80°C. After the mixture was cooled to room temperature, water (5 ml) was added and the solution was maintained at room temperature for 10 h. The precipitate was removed by suction filtration, washed with 1 1 acetic acidtwater (2 x 10 ml), dried over potassium hydroxide in an evacuated dessicator, and recrystallized from chloroform/ methanol. In this manner there was isolated pure 0,0-diphe-nyl 2-methylthio-l-(iV-phenylthioureido)ethylphosphonate (8.61 g, 94%) of mp 136 to 138°C, which exhibited spectra and analytical data in accord with the proposed structure. 

The reverse reaction of triphenyl methyl chloride (A) and methanol (B) (C6H5)3CC1 + CH3OH (C6H5)3COCH3 + HC1... 

Colorless, crystalline, optically pure (R)-(4-)-1,1,2-triphenyl-1,2-ethanediol can be recovered in >95% yield after recrystallization from methanol as described in... 

Labelling the aliphatic carbon atom with (53%) allowed comparison of the nuclear magnetic C -shifts of the covalent sp -hybridized triphenyl-C -methanol (in tetrahydrofuran solution) with that of the labelled triphenylcarbonium ions, (C8Hg)3C HS07 (triphenyl-C -methanol in sulphuric acid solution). A shift of 129-6 p.p.m. to lower shielding was observed in the triphenylcarbonium ion, as compared with the covalent triphenylmethanol. 

N-Heterocyclic carbenes are an example of a family of nucleophilic catalysts [84-87]. For instance, the polymerization of p-butyrolactone was catalyzed by l,3,4-triphenyl-4,5-dihydro-l//,l,2-triazol-5-ylidene in the presence of methanol as an initiator [86]. This reaction was carried out in toluene at 80 °C. Nevertheless, an undesired elimination (Fig. 4) reaction was observed and control of the polymerization was lost. This issue was overcome by using ferf-butanol as a co-solvent, which reacts reversibly with the free carbene to form a new adduct. Owing to the decrease in the concentration of the free carbene, the elimination is disfavored and the polymerization is then under control provided that a degree of polymerization below 200 is targeted. As a rule, the reactivity of N-heterocyclic carbenes depends on their substituents. Hindered N-heterocyclic carbenes turned out to be not nucleophilic enough for the ROP of sCL. Recently, it was shown that unencumbered N-heterocyclic carbenes were more efficient catalysts [87]. 

An alternative to activating the nitro moiety by forming the nitronate salt is the activation of an oxygen leaving group under Mitsunobu conditions (Eq. 2.15) (155,156). Treatment of methanol with diethyl azodicarboxylate and triphenyl-phosphine in the presence of ethyl nitroacetate provides the nitronate 85 in good yield. Unfortunately, only methanol has been demonstrated to be compatible with this procedure. 

Anastopoulos et al. [47] have analyzed interfacial rearrangements of triphenyl-bismuth and triphenylantimony at mercury electrode in nonaqueous solvents of high dielectric constant. These phenomena were detected as the peaks in the capacitance-potential curves at intermediate negative potentials for triphenyl-bismuth and triphenylantimony in N-methylformamide, A,A-dimethylforma-mide, dimethyl sulfoxide, propylene carbonate, and methanol solutions. 

Bei der Bestrahlung von 3,5-Diphenyl-l,2,4-oxadiazol in 2-Propanol oder Methanol erhalt man neben Phenyl-chinazolinen auch ringoffene Produkte3,B, wahrend in Diethylether Triphenyl-1,3,4-triazin in geringer Menge nachgewiesen wurde319. 

Benzylalkohole, Diphenyl- und Triphenyl-methanol reagieren mit Phosphorsaure-tris-[di-methylamid] bei hohcn Temperaturen unter Bildung der entsprechenden N,N-Dimethyl-amine in mafiigen bis guten Ausbeuten1. Aus 1-Phenyl-ethanol jedoch entsteht unter den gleichen Bedingungen als Hauptprodukt Styrol. 

Different synthetic routes have been used to prepare these carbenes (Scheme 8.6). The most common procedure is the deprotonation of the conjugate acid. In early experiments, sodium or potassium hydride, in the presence of catalytic amounts of either f-BuOK or the DMSO anion were used. ° Then, Herrmann et al. showed that the deprotonation occurs much more quickly in liquid ammonia as solvent (homogeneous phase), and many carbenes of type IV have been prepared following this procedure. In 1993, Kuhn and Kratz" developed a new and versatile approach to the alkyl-substituted N-heterocyclic carbenes IV. This original synthetic strategy relied on the reduction of imidazol-2(3//)-thiones with potassium in boiling tetrahydrofuran (THF). Lastly, Enders et al." reported in 1995 that the 1,2,4-triazol-5-ylidene (Vila) could be obtained in quantitative yield from the corresponding 5-methoxy-l,3,4-triphenyl-4,5-dihydro-l//-l,2,4-triazole by thermal elimination (80 °C) of methanol in vacuo (0.1 mbar). 

When 2.4.6-triphenyl-X -phosphorin 22 is treated with an excess of the diazonium salt, for instance, 2-methyl-4-nitro-phenyl-diazonium-tetrafiuoroborate 102 in benzene/methanol, a doubly atylated X -phosphorin 103 can be isolated... 

If l,l-bis-dimethylamino-2.4.6-triphenyl-X -phosphorin 164 is allowed to react with 2 moles of trifluoroacetic acid and a 10-fold molar excess of methanol in refluxing benzene, one of the amino groups is displaced and 1-methoxy-l-dimethyl-amino-2.4.6-triphenyl-X -phosphorin 757 can be isolated in good yield. The phos-phonium salt 165 (H can also attack C-2) is initially formed by protonation of 164 at C-4 (or C-2). Nucleophilic substitution then leads to 167 via 166 (Hettche, >). 

Methyl triphenyl phosphonium bromide (0.56 mmol) was dissolved in 10 ml of THF and treated with 1.6 M -butyl lithium (0.64 mmol) in hexane solution at 0°C. The solution was stirred for 30 minutes at 0°C and then treated with the step 2 product (0.36 mmol) and stirred an additional 2 hours at ambient temperature. The solution was treated with dilute hydrochloric acid, extracted with chloroform, dried over MgSC>4, and concentrated. The residue was purified by silica gel column chromatography using chloroform/hexane, 2 1, respectively, recrystallized using CH2CI2/ methanol, and 100 mg of product isolated. 

METHANESULFONYL CYANIDE, 57, 88 Methane, triphenyl-, 55, 11 Methanol, (4-methylphenylsulfonyl) esters, perchlorate, 57, 100... 

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