title: Synthesis of 4-aza-5,6-dimethylbenzimidazole and biosynthetic preparation of 4- and 7-aza-5,6-dimethylbenzimidazolylcobamide.
abstract: We report on the preparation of 4-aza-5,6-dimethylbenzimidazolylcobamide and 5,6-dimethyl-7-azabenzimidazolylcobamide. These vitamin B12-analogs were required as reference compounds for comparison with a corrinoid previously isolated in small amounts for Eubacterium limosum grown in the presence of 4(5)-aminoimidazole. 4(7)-Aza-5,6-dimethylbenzimidazole was synthesized from N-1-benzyl-4-nitroimidazole which was reduced to N-1-benzyl-4-aminoimidazole and condensed with 1-dimethylamino-2-methylbutan-3-one to yield N-1-benzyl-4-aza-5,6-dimethylbenzimidazole. The benzyl group of this compound was split off by catalytic hydrogenation to form 4(7)-aza-5,6-dimethylbenzimidazole. 4(7)-Aza-5,6-dimethylbenzimidazole was transformed by a growing culture of Propionibacterium shermanii into 4-aza-5,6-dimethylbenzimidazolylcobamide and 5,6-dimethyl-7-azabenzimidazolylcobamide. Both vitamin B12-analogs were almost as active as Vitamin B12 in a growth test with the vitamin B12-dependent Escherichia coli-mutant DSM 4261.
authors.affiliation: Institut für Biologische Chemie und Ernährungswissenschaft, Universität Hohenheim, Stuttgart, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Renz
authors.forename: I
authors.initials: I
authors.lastname: Pfitzner
authors.forename: B
authors.initials: B
authors.lastname: Endres
authors.forename: O
authors.initials: O
authors.lastname: Hasselwander
mesh_terms: D003038:Cobamides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D005051:Eubacterium / Q000378:metabolism; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D014805:Vitamin B 12 / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000494:pharmacology
chemical_list: C107455:4-aza-5,6-dimethylbenzimidazolylcobamide; C098331:5,6-dimethyl-7-azabenzimidazolylcobamide; D003038:Cobamides; D007202:Indicators and Reagents; D014805:Vitamin B 12