Benzophenone azine

Benzophenone Process. Benzophenone, (CgH5 )2C=0, reacts with ammonia to form diphenylmethanimine, (CgHg )2C=NH. In the presence of copper catalysts, this is oxidized with oxygen to benzophenone azine, (CgHg )2C=N—N=C(CgHg The formation of the imine and its... 

Diphenyl-diazomethan liefert bei der Elektrolyse an Platin in DMF/Tetrabutylammo-niumperchlorat Diphenylmethan, Amino-diphenyl-methan und Benzophenon-azin. Bei hohcn negativen Potentialen (—1,9 bis —2,2 V) und niedriger Ausgangskonzentration iiberwiegt Diphenylmethan (bis 51% d.Th.) das Azin dominiert erwartungsgemaB bei... 

C. Diphenyldiazomethane. In a pressure bottle are placed 19.6 g. (0.1 mole) of benzophenone hydrazone, 22 g. (0.1 mole) of yellow oxide of mercury, and 100 ml. of petroleum ether (b.p. 30-60°). The bottle is closed, wrapped in a wet towel, and shaken mechanically at room temperature for 6 hours. The mixture is then filtered to remove mercury and any benzophenone azine (Note 5), and the filtrate is evaporated to dryness under reduced pressure at room temperature. The crystalline residue of diphenyldiazomethane melts when its temperature reaches that of the room (Note 6), but it is difficult to purify and this product is pure enough for all practical purposes. The material weighs 17.3-18.6 g. (89-96%). The product should be used immediately (Note 7). 

Benzonitrile, 2,6-dimethoxy-, 22, 35 Benzophenone, 23, 99 Benzophenone azine, 24, 55 Benzophenone hydrazone, 24, 54 Benzopyrrole, 23, 42 Benzothiazole, I-amino-5-methyl-,... 

On standing, diphenyldiazomethane decomposes to yield benzophenone azine. In one of the checkers runs the product was stored at room temperature after 2 days, crystals of the azine were visible. The product at this stage was assayed by treatment with benzoic acid addition of 6.8 g. of the diazo compound in a thin stream to a solution of 17 g. of benzoic acid in 90 ml. of ether, and, after 30 minutes, extraction of the excess benzoic acid with dilute sodium hydroxide followed by distillation of the ether, gave 7.4 g. (75%) of crude benzohydryl benzoate melting at 83-85°. In the same procedure the freshly prepared diazo compound gave a quantitative yield of the crude ester. 

In addition to the rather trivial differences mentioned above, laser irradiation can also lead to products as a result of reexcitaion of the carbenes. Thus, excitation of 30 in isooctane with a pulse of the 249-nm line from a KrF excimer laser results in the formation of 9,10-diphenylanthrancene (103), 9,10-diphenylphenanthrene (104), and fluorene, in addition to tetraphenylethylene (Scheme 9.31). Conventional lamp irradiation of 30 results in the formation of benzophenone azine as a major product. None of the products mentioned above are detected. Moreover, the yield of both 103 and fluorene increased markedly with increased laser power. While the details of the mechanism of this reaction are not certain yet, it is clear from the dependence on laser power that some of these products arise from carbene photochemistry. " ... 

Recently, Murray and Trozzolo190 have reported the formation of 1,1-dichloro-2,2-diphenylethylene, benzophenone azine, tetraphenylethyl-ene, l-p-chlorophenyl-l,2,2-triphenylethylene, and 1 -p-bromophenyl-... 

The reaction of diphenykoethy) radical with benzophenone azine or benzophenone hydrazone gives 2,2,3,3-tetrapbenylaziridme384 (Eq, 23a). 

In the same study, a one-pot variant avoiding the isolation of the intermediate hydrazone was attempted. However, reduction of the crude hydrazone leads to the formation of by-products for example, in the reaction of benzophenone, a mixture of diphenylmethane and benzophenone azine was found (Scheme 4.38)64. 

Another interesting uranium(rv) system is the bis-ketimido complex, Cp 2U( N=CPh2)2, formed via the reduction of Cp 2UCl2 in ether with 2 mol of potassium graphite (KCg) in the presence of benzophenone azine, Ph2C=N N=CPh2. The molecular structure is depicted in (6)." ... 

As mentioned previously, DMSO as the reaction medium provides significant enhancement of Wolff-Kishner reaction rates and this allows the use of much lower temperatures to effect reductions. In 1962 Cram et al. introduced the use of r-butoxide in dry DMSO for the successful reduction of preformed hydrazones at room temperature. Using this process, benzophenone hydrazone (15) afforded an 88% yield of diphenylmethane (16), along with 11% of benzophenone azine (17) as side product (equation 5). However, maximum success requires very slow addition (i.e. over 8 h) of the hydrazone to the reaction solution, otherwise yields of reduced products are decreased and azine formation augmented. Thus, addition of (15) over 0.5 h in the above reaction lowered the yield of (16) to 72%, while the yield of (17) was increased to 22%. - Other successful reductions reported - include hydrazones of benzaldehyde (67%), camphor (64%) and cyclohexanone (80%). 

It was not suggested how the aryldiazomethane was initially formed but the minimum reaction temperature was lowered by 150° C on introduction of a phenyldi-azomethane catalyst. In contrast, pyrolysis of benzophenone azine gave no tetra-phenylethylene and only a trace of nitrogen . Benzophenone azine decomposes by a free radical process at 375-500 °C to afford principally benzhydrylideneimine, benzonitrile and 6-phenylphenanthridine accompanied by lesser quantities of benzene, biphenyl, diphenylmethane and benzhydrylideneaniline by the following pathways... 

Oxidative coupling of diphenylmethanimine (44) in the presence of DBU and copper(I) chloride afforded benzophenone azine (45) (77CL981 79JAP(K)24859). The best yield was achieved in dioxane or tetrahydrofuran. 

At platinum anodes and under aprotic conditions (CH3CN-LiC104), benzophenone hydrazones afford exclusively benzophenone azines (Scheme 6, a), while in MeOH/NaOMe benzophenone dimethyl acetals are formed (Scheme 6, b). At graphite anodes (MeOH/ NaOMe), diphenyldiazomethane is formed as an intermediate [122] (Scheme 6, c). 

When diaryldiazomethanes are decomposed by means of a metal salt in the presence of an alkene, 1,1-diaryIcyclopropanes are formed (see also Section 1.2.1.2.4.2.6.3.). A number of salts are able to promote the decomposition of the diazo compounds,but whatever the salt is, the cyclopropane is generally afforded in moderate to low yield due to formation of significant quantities of ketazine and benzophenone derivatives. Thus, decomposition of diphenyl-diazomethane by copper(II) sulfate in butyl vinyl ether gave l-butoxy-2,2-diphenylcyclo-propane (1) in 17% yield, benzophenone azine (2) in 14% yield and benzophenone (3) in 11% yield. ... 

Before the reaction was started the air was displaced from the reaction system with argon. A solution of diphenyldiazomethane (10.5 g, 54 mmol) in freshly distilled butyl vinyl ether (50 mL) was then added drop-wise to a boiling solution of anhyd CuSO (0.3026 g, 1.90 mmol) in butyl vinyl ether (100 mL) with stirring for 4 h. When no more Nj was liberated (780 mL, 64.5yo), the mixture was cooled (in an atmosphere of argon) and the catalyst filtered off. Butyl vinyl ether was distilled off under vacuum and the resulting residue, after separation of benzophenone azine which had crystallized out, was fractionated under vacuum. A light-yellow distillate (11.1 g bp 133-155 C/0.2 Torr), which was a mixture of l-butoxy-2,2-diphenyl-cyclopropane (1), benzophenone azine (2) and benzophenone (3), was obtained. The cyclopropyl ether was isolated from this mixture by means of column chromatography (alumina activity II, hexane/EtjO 10 1) and was finally purified by vacuum distillation yield 2.36g (16%) bp 78 - 79°C/0.015 Torr. 

Benzonitrile, 2,6-dimethoxy-, 22, 35 Benzophenone, 23, 99 Benzophenone azine, 24, 55 Benzophenone hydrazone, 24, 54 1,2-Benzopyran-3-carboxylic acid, 2-oxo-, ethyl ester, 28, 24 Benzopyrrole, 23, 42 Benzo(j) )quinolizine, 1,2,3,5,6,7-HEXAHYDRO-, 26, 40 -Benzoquinone, 26, 25 Benzothiazole, I-amino-5-methyl-, 22,16... 

Japanese chemists2 have also reported cases in which the addition of the copper chelate modifies the reactions of carbenes. Thus diphenylcarbene (thermal decomposition of diphenyldiazomethane, 1) is converted mainly into benzophenone azine (2) when generated in an aprotic medium and into 1,1,2,2-tetraphenylethane (3) when generated in a protic medium. The second reaction is considered to proceed by abstraction of hydrogen from the solvent to form benzhydryl radicals which then... 

Diazoalkane decomposition. Surprisingly, tetraphenylethylene is almost as efficient as various copper catalysts for decomposition of diazoalkanes to car-benoids. For example, diazomethane and cyclohexene in the presence of this catalyst react to form norcarane in 15 5% yield with copper catalysis the yield of norcarane is 24%. Cyclopropanations have been observed with this hydrocarbon catalyst with a variety of diazo compounds diazomethane, a-diazoacetophenone, and diazofluorene. Diphenyldiazomethane, however, is converted mainly into benzophenone azine, (C5H5)2C=NN=C(C6Hs)2. 

As expected, the product ratios were quite different in acetonitrile and acetonitrile-ris. For example, the major products were diphenylmethane and benzophenone and only a small amount of benzophenone azine when the reaction was carried out in acetonitrile whereas the percentage of benzophenone azine was ten times larger, i.e. almost equal to the diphenylmethane when the solvent was acetonitrile-hydrogen-deuterium kinetic isotope effect in acetonitrile-ris slows the hydrogen abstraction reaction which leads to diphenylmethane. These product isotope effects are only consistent with the mechanism shown in equation 28 and clearly demonstrate that the radical anion does not decompose by losing nitrogen to form the carbene radical anion when diazoalkanes are reduced. 

The increase in the isotope effect as the percent water in the solvent increases is accompanied by the expected change in the products of the reaction. As the percent water increases, the amount of the diphenylmethanol increases and the amount of tetraphen-ylethylene and benzophenone azine decreases. The larger isotope effect is observed when the water concentration is higher, because the slow proton transfer step of the acid catalysed reaction becomes more important as the carbocation pathway accounts for a greater portion of the reaction. Obviously, no isotope effect is observed at low concentrations of water where this reaction is not significant. 

The thermal decomposition of diphenyidiazomethane in aprotic (hydrocarbon) solvents gives benzophenone azine and tetraphenylethane as the principal identifiable products , while in hydroxylic solvents the appropriate derivative of benzhydrol accompanies the azine . Kinetic studies of the decomposition of diphenyidiazomethane in xylene and in 1-methylnaphthalene at about 100°C have shown that the reaction is first-order in diazo compound this has been interpreted as supporting the intermediate formation of di-phenylcarbene, viz-... 

Triethylphosphine benzophenone azine, (C2H5)gP = N—N = C(C,Hj)g, is obtained by the interaction of diphenyldiazomethane and triethylphosphine in petroleum ether, employing a carbon dioxide atmosphere and cooling, the phosphazine soon separating in yellow... 

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