Imidazole 2-phenylbenzimidazole

Above 170 °C the amidrazone ylide (36) decomposes with loss of triethylamine and concurrent cyclization to give an 85% yield of 2-phenylbenzimidazole (Scheme 19) (B-75M140800). Poorer yields ( 40%) are obtained when N-benzyl-o-nitroaniline is pyrolyzed in the presence of iron oxalate. No doubt this last reaction is similar in many respects to the reactions shown in Scheme 2. Both 2-phenyl-imidazoles and -benzimidazoles (as well as other 2-substituted analogues) can be obtained as a result of thermal rearrangement of the 1-substituted isomers (Section 4.07.1.2.2), by radical substitution methods (Section 4.07.1.7) or via the 2-lithio derivatives (Sections 4.07.1.6, 4.07.3.7). 

There are reports that benzimidazoles can be made by eyclization of N-arylimidoyl nitrencs generated by photolysis of sulfimides of 1-aryltetrazoles [3, 4]. These should be compared to the related imidazole synthesis in Section 6.1.2.3. Examples include the formation of 2-phenylbenzimidazole (42%) from 1,5-diphenyltetrazoIe [5], and 5-phenoxybenzimidazole (36%) from 5-phenoxy-l-phenyltetrazole [6]. These reactions have little apparent synthetic importance. 

C1-C3 alkanes and alkenes, H2S, CS2, benzene, toluene gaseous products Hj, NH3, HCN, and CHj products nonvolatile at ambient temperature after approx, 50% weight loss benzimidazole (29 8%), benzoxazole (4 9%), 2-methylbenzimidazole (7.3%), 2-phenylbenzimidazole (24.3%), 2-(3-methylphenyl)benzimidazcile (5.3%), 5-(3-aminophenyl)-benzimidazole ( 6%), 2-(3-cyanophenyl)-benzimidazole (7.8%), 5.5 -bibenzimidazole (4 4%), 2-phenyl-5-(3-aminopheny )benzirnidazole (4 4%), 2-phenyl-5,5 -bibenz-imidazole (19%), 2-phenyl-5-(benzoxazolo)benzimidazole (0,3%) phenol, terephlhalodinitrlle, benzonitrile. 4,4 -diaminodiphenyl, H2, CO. NH3, HCN. traces of aniline, carbonaceous residue... 

H-Benzimidazole-6sulfonic acid, 2-phenyl- EINECS 248-502-0 Ensulizole Eusolex 232 Neo Heliopan Hydro Novantisol Phenylbenzimidazole sulfonic acid 2-Phenylbenzimidazole-6 sulfonic acid 2-Phenyl-1H-benzimldazole-6sulfonic acid 2-Phenyl-1H-benz-imidazole-5-sulphonic acid. UV-B filter for sunscreen formulations. Used in creams, lotions and subscreens. Solid mp >300°. Haarmann i Reimer GmbH. 

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