Benzimidazole group

The unsymmetrical derivative, L2, in which one benzimidazole group is replaced by a 2-pyridyl moiety, and its complexes with europium and terbium have been further studied for their photophysical properties (37). The coordinated nitrate anions in the [ ( 2)( ) ]... 

Martin, N. Biinzli, J.-C. G. McKee, V. Piguet, C. Hopfgartner, G. Self-assembled dinuclear lanthanide helicates substantial luminescence enhancement upon replacing terminal benzimidazole groups by carboxamide binding units. Inorg. Chem. 1998, 37, 577-589. 

The benzimidazole group of anthelminthics is derived from the simple benzimidazole nucleus and includes the thiabendazole analogues and the benzimidazole carbamates. Substitution of side chains and radicals on the benzimidazole nucleus gives rise to the individual members of this group (Fig. 4.1). 

The roles of axial ligand and the protein in controlling Co—C bond homolysis have been explored. The benzimidazole group exists in on and off configurations. Model studies show... 

Fig. 9.4. Vitamin B, coenzyme structure, showing bonding of deoxy-adenosyl carbanion to cobalt(III). Four of the five N atoms bonded to Co are furnished by the corrin ring and one is from a benzimidazole group.

Methylcobalamin is a red crystalline solid that is stable in the solid state under ambient conditions. In solution, methylcobalamin is very light sensitive, undergoing homolytic cleavage of the cobalt carbon bond. In dilute acid, protonation of the axial benzimidazole group causes a dramatic change in color from red to... 

The foUowing condusions may be obtained from these results (1) The catalytic efficiency increases with pH, because of the increaang involvement of the benzimidazole anion. Lower pK j value of the benzimidazole group is effective in this reject However, the benzimidazole anion is not a good nudeophile toward the anionic substrate NABS because of electrostatic repulsion. (2) Polyvinylbenzimidazole 2 is a better catalyst than benzimidazole. Although this was daimed to be due to the bifunctional catalysis of the pdyn r, substrate binding and microenvironmental effects cannot be neglected. 

Fig. 1. Catalytic entities bis(dimethylamid)phosphoryl compound (8), dimethylpyrazole groups (9) and benzimidazole groups (10) grafted on the surface of a silica carrier.

Thiophanate methyl (74) is, like thiabendazole (54), a member of the benzimidazole group of fungicides since it is metabolised in vivo to carbendazim (83), which is the active entity. Thiophanate methyl is synthesised by condensation of o-phenylenediamine (82) with potassium thiocyanate and methyl chloroformate (Scheme 17). The benzimidazoles owe their fungicidal action to the inhibition of cell division in the fungus due to interference with the microtubular assembly. 

An essential property of coenzyme B12 is the weakness of its cobalt-carbon bond, which is readily cleaved to generate a radical. To facilitate the cleavage of this bond, enzymes such as methylmalonyl CoA mutase displace the benzimidazole group from the cobalamin and bind to the cobalt atom... 

Prilosec, Rapinex, Zegerid) and its S-isomer, esomeprazole (Nexium), lansoprazole (Prevacid), rabeprazole (Aciphex), and pantoprazole (Protonix). These drugs have different substitutions on their pyridine and/or benzimidazole groups but are remarkably similar in their pharmacological properties. Omeprazole is a racemic mixture of R- and S-isomers the S-isomer, esomeprazole (S-omeprazole), is eliminated less rapidly than R-omeprazole, which theoretically provides a therapeutic advantage because of the increased half-life. Despite claims to the contrary, all proton-pump inhibitors have equivalent efficacy at comparable doses. 

SAR of Astemizole. The piperidino-amino-benzimidazol group seems to be absolutely an essential requisite for the Hj-receptor affinity besides, helping appreciably to the persistent receptor binding which ultimately gives rise to the prolonged action. 

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