4-hydroxyphenyl benzimidazole

Poly(arylene ether benzimidazole)s have received more attention than any other PAE containing heterocyclic units. This is due primarily to their unique combination of properties even at relatively low molecular weights and their potential for use in several high performance applications. The initial report in 1991 involved polymers from the reaction of 3 different bis[(4-hydroxy-phenyl)benzimidazole]s with various activated aromatic difluoro monomers as shown in Eq. (10) [37]. The bis[(4-hydroxyphenyl)benzimidazole]s were prepared from the reaction of aromatic bis(o-diamines) and phenyl-4-hydroxybenzoate in diphenyl sulfone. The use of 4-hydroxybenzoic acid would obviously reduce the... 

Sulfonated PAES copolymers with intermolecu-lar ionic crosslinkable moieties, i.e., 5,5 -bis[2,4-(hydroxyphenyl) benzimidazole], have been synthesized [131]. The synthesis of the monomer is shown in Figure 7.17. 

Among ring-fused systems, the 3-(o-aminoaryl)benzisoxazole (506) underwent rearrangement on refluxing in THF with sodium hydride or lithium aluminum hydride. In this case the 3-(o-hydroxyphenyl)benzimidazole (506a) was obtained. 

Phosphorus heterocycles 246 derived from hydroxyphenyl benzimidazole and aminophenyl benzimidazole undergo oxidative cycloaddition with 3,5-di-/fV/-butyl-l, 2-bcnzoquinonc to give a mixture of 247 and 248 (Equation 60) <2004HAC307, 2004HAC321>. Oxidative addition of ort o-chloranil to bis- and tetrakis-cyclodiphos-phazene compounds gives bis- and tetrakis-spirophosphoranes, for example, 41 (Equation 61). 

In 2-(2 -hydroxyphenyl)benzimidazole (Scheme 15), the proton transfer between the keto 38B and the enol 38A forms in the ground state leads to a large difference in energy, which is explained by the stabilization brought in the enol form by the aromaticity of the six-membered ring.10 Intramolecular... 

The effects of a-, (3-, y-, and 2,6-di-o-methyl-(3-CDs on the ground- and excited-state properties of 2-(2 -hydroxyphenyl)benzoxazole (HBO), 2-(2 -hydrox-yphenyl)benzothiazole (HBT), and 2-(2 -hydroxyphenyl)benzimidazole (HBI) (42) in aqueous media have been investigated using fluorescence [184], The molecules form 1 1 complexes with a reasonably high association constant, and they enter the cavity axially from the wider-rim side of (3-CD with the benzazole... 

Semi-empirical AMI-SCI calculations have been performed to rationalize the photophysical behavior of two series of compounds one comprising of 2-(2 -hydroxyphenyl)benzoxazole, 2-(2 -hydroxyphenyl)benzimidazole (HBI), and 2-(2 -hydroxyphenyl)benzothiazole, and the other of 2-(2 -hydroxyphenyl)oxazole (HPO), 2-(2 -hydroxyphenyl)imi-dazole (HPI), and 2-(2 -hydroxyphenyl)thiazole (HPT). These compounds exhibit intramolecular rotation as well as excited state intramolecular proton transfer (ESIPT). The results suggested that for the first series of compounds two rotational isomers are present in the ground state of HBO and HBI while HBT has a single conformer under similar circumstances. For the other series, existence of rotamers depends very much on the polarity of the environment <2003IMS335, 2002JST(604)87>. 

Other Names Phenol, o-2-benzimidazolyl- 2-(lH-Benzimidazol-2-yl)phenol 2-(2 -Hydroxyphe-nyl)benzimidazole 2-(2-Benzimidazolyl)phenol 2-(2-Hydroxyphenyl)-lH-benzimidazole 2-(2-Hydroxyphenyl)-benzimidazole 2-((9-Hydroxyphenyl)-benzimidazole HBI NSC 32819 CA Index Name Phenol, 2-(lH-benzimidazol-2-yl)-CAS Registry Number 2963-66-8 Merck Index Number Not listed Chemical Structure... 

Leonard, J. T. Jeyaseeli, L. Shivakumar, R. Gunasekaran, V. Synthesis, antiinflammatory and antibacterial activities of 2-hydroxyphenyl benzimidazoles. Asian J. Chem. 2005,17, 2674-2678. 

A mixture of equimolar amounts of salicylic acid, o-phenylenediamine, and PjOj heated until reaction starts 2-(o-hydroxyphenyl) benzimidazole. Y ca. 90%. I. S. Ioffe and D. N. Glebovskil, 30, 1158 (1960) C. A. 55, 519b. 

Eriochrome geranol, E-00015 2961-47-9 4-(l-Butylpentyl)pyridine, B-00635 2963-66-8 2-(2-Hydroxyphenyl)benzimidazole,... 

Benzimidazole, 3-( o-hydroxyphenyl)-synthesis, 5, 158 Benzimidazole, 1-isopropyl-reactions... 

As in the case of benzothiazoles and benzimidazoles, the excited-state proton transfer in 2-(2 -hydroxyphenyl)benzoxazole was studied both experimentally and computationally. The results closely resemble the observations for the other species The cw-enol form is preferred in the Sq ground state and the cw-keto form in the 5i excited state. Moreover, the proton transfer appears to be due to vibrational relaxation rather than thermal activation, suggesting that the aromatic ring has an impact on the transfer reaction of these systems [95JPC12456, 99JST255]. 

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