Benzophenone anil

The carbon-nitrogen double bond in imines is reduced at less negative potentials than the corresponding carbonyl function. Also imine radical-anions are more basic than carbonyl radical-anions. Imines with at least one phenyl substituent on the carbon-nitrogen double bond are sufficiently stable for examination in aprotic solvents and reversible one-electron reduction of benzaldehyde anil [179] or benzophenone anil [ISO] can be demonstrated with rigorous exclusion of moisture. 

Benzophenone anil [184] and benzaldehyde anil [185] are both sufficiently stable in aqueous solution above pH 5 for polarographic examination. Both compounds show two one-election waves in the less alkaline region, as illustrated for benzophenone anil in Figure 10.3. For the more anodic wave, E./, varies with pH due to the rapid establishment near the electrode surface of the equlibria ... 

Addition of aryl isocyanates to benzaldehyde and benzophenone anils... 

Saunders and Ware [165] examined its thermal decomposition in the molten state at 170 - 200°C and found it gives a benzophenone anil (C6H5)2C=NC6H5. They suggest the following mechanism for the decomposition... 

Triarylmethyl azides (13) rearrange thermally (170-190°) or photochemically (room temperature) to benzophenone anils... 

The observation that phenanthridine is formed in 2% yield when the anil (112a) is irradiated at 10°, whereas benzophenone anil (113),... 

Triphenylmethyldifluoramine (I) reacts rapidly with n-butyllithium to yield n-octane and benzophenone anil (II). With equimolar quantities of the reactants the reaction was incomplete, and some I was recovered. Only 40% of the fluorine was converted to fluoride ion under these condi-... 

In reactions involving triphenylmethyldifluoramine (I), rearrangement of the nitrene (VIII b) appears to be favored energetically, since benzophenone anil (II) was the only product found. II has been reported as the principal product of thermal decomposition of triphenylmethyl, N-triphenylmethylhydroxylamine, and a number of related compounds... 

The residue was recrystallized from methanol to yield 2.15 grams (42%) of yellow crystals, m.p., 112°-113° C., which were identified by infrared and elemental analysis as benzophenone anil. 

A case of concomitant crystallization which involves configurational isomerism of the benzophenone anil 3-XXII has been reported by Matthews et al. (1991) was discussed in Section 1.2.2. 

The thermal decomposition of triaryl methyl azides is first order, and the major products are mixtures of benzophenone anils . For the reaction... 

Some aspects of this topic have been reviewedThe thermal decomposition of alkyl azides was first demonstrated by Senior" , working with Stieglitz. He showed that benzophenone anils, nitrogen and tars were obtained by heating triarylmethyl azides at temperatures of about 200°. The effect of substituents on the nature of the products was considered also, but the analytical techniques available were quite crude. The work was repeated and extended more recently, and will be discussed later. 

The thermolysis of triarylmethyl azides to give benzophenone anils (144) and (145) has been carefully studied by Saunders and coworkers Table 2 gives the kinetic data for the thermolysis of... 

When the azido group is linked to a tertiary carbon atom, an alkyl or aryl shift occurs, and the resulting A -substituted azomethines can often be isolated. Trityl azide (53) yielded, by action of heat or light , benzophenone anil (54). 

In nonaqueous solution azomethine compounds are usually stable, and several types have been reductively coupled with alkyl halides or carbon dioxide. Benzophenone anil (III) gives thus on reduction in DMF-TBAI in the presence of methyl chloride a mixture of N- and C-methylated and N,C-dimethylated products [28] ... 

Decarbonylation. Sheehan and Frankenfeld treated a-imilino-a,a-diphenylacetic acid (1) with tosyl chloride in pyridine with the expectation of obtaining the N-tosyl derivative but instead characterized the products as benzophenone anil (3), carbon monoxide, and pyridinium tosylate. They postulate the intermediate formation of the mixed anhydride (2). 

Benzophenone anil 882 Benzophenone (10 g) and aniline (10 g) at 160° are treated during 0.5 h with freshly crushed, anhydrous zinc chloride (1-2 g). After cooling, the yellow melt is boiled with a little benzene or ether. The yellow anil (12 g, 85%), m.p. 117°, crystallizes from the solution. 

Benzophenone anil (7 g) is dissolved in benzene (50 ml) in a hydrogenation vessel and treated with dry hydrogen chloride, which precipitates the yellow hydrochloride. The hydrogen chloride is then replaced by hydrogen sulfide, and the vessel is shaken for 6 days under the pressure from a Kipps apparatus. The resulting deep blue solution is filtered under carbon dioxide from the precipitated aniline hydrochloride and unchanged benzophenone anil hydrochloride, the benzene is evaporated in a stream of carbon dioxide, and the residue is fractionated. Thiobenzophenone (3 g) distils at 176-178°/18 mm as a deep blue oil, which solidifies on cooling but remelts in the warmth of a hand. 

With benzophenone anil and phenylmagnesium bromide 1,4-addition occurs (yield 42%) 235... 

Diamino-aniIino]-flaoren 13 II146. 4. 4".Siamino-fuch3on.imid 13, 754. 4.4. Oiamino-benzophenon-anil 14 II57. Anthruiilsiwre-[N.N -dipha2rl-aimdiB]... 

Imines also undergo [2-I-2-I-2] cycloaddition reactions with isocyanates. Usually, one equivalent of the imine reacts with two equivalents of the isocyanate. For example, heating of an excess of azomethines or benzophenone anils with isocyanates affords six-membered ring [2+2- -2] cycloadducts (see Section 3.3.1.4). This reaction proceeds in a stepwise manner, as indicated by the formation of different cycloadducts when different isocyanates are used. Also, reaction of A-alkyl- and A-aryl formamidines with alkyl- or aryl isocyanates on heating or in the presence of zinc chloride as the catalyst gives 2 1 (iminedsocyanate) adducts. Some examples of these reactions are listed in Table 3.10. 

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