No 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

The action of ammonia on benzoin has been studied previously by Laurent,1 Erdmann,2 and Japp and Wilson.3 These investigators found that the reaction leads to three products-amarone (C28H22N2, m.p. 245°)[also called benzoinimide (Erdmann) and ditolane-azotide (Japp and Wilson)], benzoinam (C28H23N2O, m.p. 190°-220°d epending on the rate SUMMARY 1. The action of ammonia on benzoin in boiling acetic acid yields amarone, dihydroamarone, and 2-methyl-4,5-diphenylglyoxaline.2. Desylamine is assumed to be an intermediate product in this reaction. It behaves like benzoin toward ammonia in acetic acid.3. In the presence of formic acid the formation of pyrazines is suppressed, the isolated products being iV-desylformamide and 4,5-diphenylglyoxaline.