Benzimidazoles functionalization

This chapter gives an introduction to the basic concepts of magnetism in organic paramagnetic soft matter materials. Key concepts are emphasized using example case studies. Detailed analysis covers radicals functionalized with phenols and with benzimidazole functionalities, which induce various degrees of crystal self-assembly, depending on specific structures. A review with over 200 references and notes. 

S. Chavan, W. Maes, J. Wahlen, P. Jacobs, D. De Vos, W. Dehaen, Benzimidazole-functionalized dendrons as molybdenum supports for selective epoxidation catalysis, Catal. Commun. 6 (2005) 241. 

Seber G, Brook DJR, Taylor PS, Cassaro ILAA, Lahti PM. Magnetostmcmral effects of changing spin unit structure and molecular connectivity on IH-benzimidazole functionalized radicals. Polyhedron. 2014 76 36-44. 

Tang T, Shi Z, Yin J. Poly(benzimidazole) functionalized multi-walled carbon nanotubes/100% acidified poly(hydroxyaminoether) composites synthesis, characterization and properties. Mater ChemPhys 2011 129(l-2) 356-64. 

A series of benzimidazole and benzimidazolone derivatives from the Janssen laboratories has provided an unusually large number of biologically active compounds, particularly in the area of the central nervous system. Reaction of imidazolone itself with isopropenyl acetate leads to the singly protected imidazolone derivative 51. Alkylation of this with 3-chloro-l-bromopropane affords the functionalized derivative Use of this... 

Therapeutic Function Anthelmintic Chemical Name 2-(4-thiazolyl)-1 H-benzimidazole Common Name -Structural Formula ... 

Townsend L, Devivar R, Turk S, Nassiri M, Drach J (1995) Design, synthesis, and antiviral activity of certain 2,5,6-trihalo-l-(beta-d-ribofuranosyl)benzimidazoles. J Med Chem 38 4098 105 Turlure F, Devroe E, Silver PA, Engelman A (2004) Human cell proteins and human immunodeficiency virus DNA integration. Front Biosd 9 3187-3208 Umehara T, Fukuda K, Nishikawa F, Kohara M, Hasegawa T, NisUkawa S (2005) Rational design of dual-functional aptamers that inhibit the protease and helicase activities of HCV NS3. J Biochem 137 339-347... 

The key synthetic challenges in the target molecule 1 were the chiral 2-arylpyrrolidine fragment, the densely functionalized benzimidazole ring, and the hindered biaryl ether linkage. 

The incorporation of benzimidazole, in addition to mimicking the imidazole donor function, would result in distortions in coordination geometries, owing to its steric bulk. From this standpoint a number of complexes have been reported (Table 3).87-89... 

C-H functionalizations of benzimidazoles have been described and are thought to involve an Rh(m) hydride. Hydrochloride salts of bulky electron-rich phosphines were found to be useful additives (Equations (115) and (116)). 

One of the first examples of this type of blend was composed of SPEEK or SPES as the acidic component and diaminated PES, poly(4-vinylpyridine) (P4VP), poly(benzimidazole) (PBl), or poly(ethyleneimine) (PEI) as the basic component. " For blend lEC values of 1.0 meq/g, conductivity values were reported to be good, as was H2/O2 EC performance. Thermal stabilities for these blends was also demonstrated to be high (>270°C). Other examples of acid-base PEMs include blends of SPPO and PBI, sulfonated poly(phthalazinone ether ketone) and aminated SPES, SPIs and aminated Pls, and SPEEK with PES bearing benzimidazole side groups, ° as well as an unusual example in which the blend is composed of sulfonated, hyper-branched polyether and pyridine-functionalized polysulfone. ... 

Highly stable 4-(benzimidazol-2-yl)-2,6-di-t-butylphenoxyl radicals have been synthesized. Their hydrogen-bonding functionality offers prospects for use in molecular magnetic materials. ... 

Polyimides are obtained from amine and carboxyl reactants when the ratio of amine to acid functional groups is 1 2. If reactants with the reverse ratio of amine to acid functional groups are employed, polybenzimidazoles (PBI) are produced for instance, polymerization of 3,3 diaminobenzidine and diphenyl isophthalate yields poly[(5,5 -bi-liT-benzimidazole]-2,2 -diyl)-l,3-phenylene] (Lilia) (Eq. 2-216) [Buckley et al., 1988 Hergenrother, 1987 ... 

Due to the biological significance of some azoles (pyrrole, indole, imidazole, benzimidazole) and the consequences of acid-base equilibria in their functions, a continuous interest in the behavior in water is to be expected. To quote a significant approach, imidazole is being used to determine the intra- and extracellular acidity by H-NMR (82MI4 86UP13). 

The keto-acid function is then converted to a pyridazinone by treatment with hydrazine (35-4). Catalytic hydrogenation then converts the nitro group to an amine (35-5) cyclization of the resulting ortho amino amide by means of a strong acid leads to the formation of the corresponding benzimidazole. There is thus obtained pimobendan (35-6) [37]. 

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