Benzimidazole 5-sulfonic acid

Chichibabin reaction, 5, 409-410 sulfonation, 5, 429 synthesis, 5, 160, 161, 457-498, 496 tautomerism, 5, 365 toxicity, 1, 139 UV spectra, 5, 356, 357 2H-Benzimidazoles 3,3-dioxides synthesis, 6, 407 2V,7ST-dioxides reactions, 5, 456 Benzimidazoles, aryl-oxidation, 5, 433 Benzimidazoles, nitro-mass spectra, 5, 359 reduction, 5, 441 Benzimidazole-2-sulfonic acids reactions... 

Azolesulfonic acids frequently exist as zwitterions. The usual derivatives are formed, e.g., pyrazole-3-, -4-, and -S-sulfonic acids all give sulfonyl chlorides with PCI5. The sulfonic acid groups can be replaced by nucleophiles under more or less vigorous conditions, e.g., by hydroxy in imidazole-4-sulfonic acids at 170C, and by hydroxy or amino in thiazole-2-sulfonic acids. Benzimidazole-2-sulfonic acids react similarly. 

The 2-halo-substituted benzimidazoles, then, more or less readily react with ammonia, amines and hydrazines (80AHC 27)241,70AHC(12)103,74CRV279), It is likely that the formation of the 2-pyridinium compound (123) when cycloheptimidazolin-2(l//)-one reacts with phosphoryl chloride in pyridine occurs via the 2-chloro intermediate (Scheme 56). The sulfur function of benzimidazole-2-sulfonic acid can be displaced by amino or alkylamino groups. 

Sulfinic acids and sulfoxides are not particularly common, being readily oxidized to the sulfonic acids and sulfones, respectively. Sulfonic acids have high melting points and probably exist as zwitterions. They are amphoteric, but mainly display the characteristics of weak acids. The sulfonic acid group activates an adjacent halogen to nucleophilic displacement, and may itself be displaced, e.g. reaction of alkylamines with benzimidazole-2-sulfonic acid. Imidazolesulfonic acids resist esterification and acid chloride formation, and are only hydrolyzed by concentrated hydrochloric acid at 170 °C the 2-isomers are more resistant than the 4- or 5-isomers. Aqueous alkali converts the free acids into hydroxy derivatives. Sulfonyl chlorides are accessible via the thiols (Section 4.07.3.6.1) which react with ammonia to form sulfonamides, or are reduced by tin(II) chloride to thiols (77JHC889). 

Unlike other sulfonic acids, benzimidazole-2-sulfonic acids are fairly easily converted into the 2-thiones merely by heating with ammonium formate at 150-160 °C. The reaction is accompanied by some desulfurization. When the ammonium salt of the sulfonic acid is heated with formamide the products are the 2-thione and 2-aminobenzimidazole <84CHE224>. 

Boaventura et al. [12] reported the generation of polytriazole based proton conducting membranes. Sulfonated polytriazole membranes were doped with three different agents IH-benzimidazole-2-sulfonic acid, benzimidazole and phosphoric acid. Figure 1.13 also shows the storage modulus and tan 6 curves for pure polymer... 

In 1984, Tsupak and co.[64] synthesized 2-(l-adamantyl)benzimidazole (68) with 45% yield by substitution of sulpho group in benzimidazole-2-sulfonic acid with adamantly radical. The reaction was carried out in aqua acetonitrile solution. The adamantyl radical was obtained by oxidativ decarboxylation of adamantanecarboxylic acid with ammonia persulfate in silver nitrate aqua solution. 

Tsupak, E. B. Vikhryanova, I. V. Free radical alkyldesulfonation of benzimidazole-2-sulfonic acid. Chemistry of Heterocyclic Compounds, 1984 Vol. 20, No 12, 1401. Translated from Khimiya Geterotsiklicheskikh Soedinenii, 1984No.l2,1695. 

On the other hand, some experimental results are in agreement with the predominance of path b (Fig. 24) they arc due in particular to the aptitude of a very large number of substrates to react readily with aldehydes (see references reported for 12 and Ref. 274). Indeed, several successful syntheses of Mannich bases have been carried out starting from the hydroxymethyl derivative of the substrate, as reported for C-Mannich bases obtained from ferrocenyl derivatives,- nitroalkanes. - and hydrogen cyanide as well as for N-, S-, P-Mannich bases of benzimidazoles, sulfonic acids,- phosphines, etc. 

Isoamylmethoxy cinnamate (IMC) Ethylhexylmethoxy cinnamate (EHMC) Octocrylene (OCR) Polysilicone 15 (BMP) Benzophenone-3 (B-3) Benzophenone-4 (B-4) Phenyl benzimidazole sulfonic acid (PBSA) 4-Methyl benzyhdene camphor (MBC) Ethylhexyl triazone... 

Imidazole- and benzimidazole-2-thiols usually exist largely as the thione tautomers. The thiol (thione) group is susceptible to alkylation (especially in alkaline media), and can be oxidized to sulfide, disulfide and sulfonic acid. This oxidation can often be carried out quite selectively by careful choice of oxidizing agent. The sulfur function can be removed with nitric acid, iron(III) chloride, hydrogen peroxide or, most commonly, Raney nickel. Alkyl- and arylthio groups can be oxidized to sulfoxide or sulfone. 

A-Phosphorylated imidazoles and benzimidazoles can be made by direct phosphorylation by halides, esters, amides, amidoesters, isocyanates, and thiocyanates of phosphorus-containing acids, or from reaction of phosphonic or phosphinic imidazolides with a sulfonic acid or anhydride <82CB1636>. Stable charge transfer complexes are produced when a 1 1 or 1 2 ratio of imidazole (or benzimidazole) and sulfur trioxide are refluxed in ether, dioxane, THE, or 1,2-dichloroethane. These complexes are stable on storage in the absence of water and have sharp melting points. Indeed, the benzimidazole SO3 complex must be boiled for five hours in water to decompose it. On fusion, the complexes form the C-sulfonic acids (see Section 3.02.5.3.3) <87CHE1084>. Sulfonyl chlorides readily A-sulfonate imidazoles <94JMC332>. 

When 2-alkylsulfinyl-, 2-arylsulfinyl-, and 1,2-aralkylsulfinyl-benzimidazoles react with thiols, the unsymmetrical disulfides are obtained (instead of the symmetrical ones), together with ipso-substitution products. The reaction is believed to be initiated by protonation of the benzimidazole nitrogen. The sulfenic acid is then eliminated after the ipso-substitution by thiolate. The sulfonic acid, once formed, is so unstable that it reacts immediately with thiol or dimerizes to form thio-sulfinates from which the unsymmetrical disulfides are derived (Equation (56)) <87JOC4620>. 

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. 

Poly-2,5(6) benzimidazole Methane sulfonic acid, HCOOH/cresol Solvent nature affects the morphologies of polymer films thus the extensibility and mechanical properties of films. DSC, Rheovibron viscoelastometer, WAXS [Wereta et at, 1978]... 

The 1,2 -isomer (78) has only been prepared, in low yield, by thermolysis of 2-phenylthiobenzimidazole (75BCJ956). The 1 -methyl and 2,l -dimethyl derivatives of 78 have been reported from reactions of the appropriate benzimidazole with l-methylbenzimidazole-2-sulfonic acid (75KGS826) and 2-chloro-l-methylbenzimidazole (67MI1). The 2-oxo derivative of 78 has been prepared from 2-chlorobenzimidazole (82AJC775), and the 2-... 

Benzene-4-sulfonic acid, l-hydroxy-2-(2-hydroxy-6-suIfo-l-naphthylazo)-6-(2-hydroxy-l-naphthylazo)-metallochromic indicator, 556 Benzimidazole, 2-(o-hydroxyphenyl)-raercury determination, 532 Betrzoic acid complexes linkage isomers, 186 a-Benzoin oxime in gravimetry, 530 Benzothiazole, hydroxy-in gravimetry, 531 Benzothiazole, mercapto-in gravimetry, 534 Benzothiazole, 2-mercapto-cadmium complexes liquid-liquid extraction, 547 Benzoxazole, 2-(o-hydroxyphenyl)-cadmium determination, 531 Benzylamine, a-methyl-Al,7V-dimethyl-complexes chirality, 199 Berry pseudorotation, 39 Beryllium analysis, 523... 

H-Benzimidazole, 1 -[3-[4-(diphenylmethyl)-1 -piperazinyl] propyl]-. See Diphenylmethyl piperazinyl benzimidazole 1H-Benzimidazole-5-sulfonic acid, 2-phenyl-, monosodium salt. See Sodium phenylbenzimidazole sulfonate IH-Benzimidazolesulfonic acid, 2-phenyl-, sodium salt, compd. with 2,2, 2"-nitrilotris (ethanol). See TEA-phenylbenzimidazole sulfonate... 

N-Phenyl-1,4-benzenediamine sulfate. See N-Phenyl-p-phenylenediamine sulfate a-Phenylbenzenemethanol. See Benzhydrol Phenylbenzimidazole sulfonic acid CAS 27503-81-7 EINECS/ELINCS 248-502-0 Synonyms 2-Phenylbenzimidazole-5-sulfonic acid 2-Phenyl-1H-benzimidazol-5-sulfonic acid Classification Aromatic organic compd. 

Synonyms 1H-Benzimidazole-5-sulfonic acid, 2-phenyl-, monosodium salt 2-... 

A variety of high-temperature-resistant PBIs were synthesized and reported in the Uterature. The most widely used PBI is poly[2,2 -(l,3-phenylene)-5,5-benzimidazole] (known as m-PBI) [22]. The other variations are poly[2,2 -( 1,4- phenylene)-5,5 -benzimidazole] (known as p-PBI) [13], poly(4,4 -diphenylether-5,5 -bibenzimidazole) (OPBI) [23], poly(2,5-benzimidazole) (AB-PBI) [24], pyridine-based PBI [25], sulfonated PBI [26], hyperbranched polybenzimidazole (HPBI) [27], naphthalene-based PBI [28], fluorinated PBI [29], PBI block copolymer [30], sulfonated PBI copolymer with sulfone or sulfonic acid groups in the backbone [31,32], PBFnano-composite [33], cross-linked PBI [34], and many others. Different approaches have been taken by the researchers to modify the structure and properties of the fluorinated PBI. A detailed summary of these works is discussed below. 

Synonyms phenylbenzimidazole sulfonic acid phenylbenzimidazol-5-sulfonic acid Eusolex 232 Novantisol 2-phenyl-iH-benzimidazole-5-sulfonic acid... 

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