The Action of Ammonia on Benzil

Abstract

Interest in the action of ammonia on benzil dates back nearly a century to the observation of Zinin,1 who found that the reaction in aqueous alcoholic medium at 70°y ielded ethyl benzoate and a colorless, glistening, crystalline product which he named Azobenzil. Soon afterward, Laurent2 made a more systematic study of the reaction in alcoholic solution, and isolated three substances termed by him Imabenzil, Benzilimide, and Benzilam. At the suggestion of Zineke,3 Henius4 *reinvestigated the reaction. He identified Zinin's azobenzil with Laurent's benzilam, and found that in alcoholic solution at 130°imabenzil disappeared after one hour, and on continued heating the remaining benzilimide-benzilam mixture gave way to a mixture of benzilam and lophine.In the meantime, Japp6 had also attacked this problem and published the first reliable analyses of Laurent's products. He suggested the following structures for benzilimide (I) and benzilam (II); structures which

Research on the reaction of furil with ammonium acetate

“…However, unexpected results were obtained. The yield of the product I was lower (65.4％), and the subordinate amount of 2,4,5-tri(furan-2-yl)-1H-oaxzole corresponding to benzilam (2,4,5-triphenyl-1H-oaxzole) in the literature [13] was not obtained. The compound with structure I and the new byproducts with structures II and III which were isolated and purified by recrystallization after C18 reversed phase column were observed, respectively, clearly resulting from the nucleophilic addition reaction of ammonia to furil.…”

“…In our first attempt at the reaction, it was expected that furil was treated with ammonium acetate in glacial acetic acid to obtain product I with the yield as high as that of the obtained 2,4,5-triphenylglyoxaline from the reaction of benzil and ammonia [13]. However, unexpected results were obtained.…”

“…The result indicated that the carbon atom nearby 142 ppm in 13 C NMR spectrum is not a quarterly carbon atom but furan-3C, furan-4C and furan-5C shared the same one hydrogen. Further proof of the structure for the product I was based on Xray structure determination.…”

“…The reaction of furil with ammonium acetate was carried out according to the literature [13]. A mixture of furil (4.32 mmol, 0.82 g) and ammonium acetate (52.60 mmol, 4.05 g) in glacial acetic acid (15 mL) was refluxed.…”

“…The main product 2,4,5-triphenylglyoxaline was confirmed as the structure for lophine. Subsequently, Davidson et al further researched the reaction in 1937, corrected the structure of benzilimide, suggested a more rational formula for imabenzil, and offered a mechanism on the action of ammonia with benzil [13]. Until 1979, Dora et al studied the condensation of furil(1,2-di(furan-2-yl)ethane-1,2-dione) with furfural in refluxing glacial acetic acid, the yield of 2,4,5-tri(furan-2-yl)-1H-imidazole obtained was only 30% [7].…”