Benzimidazole-5-sulfonyl chlorides

N H-Benzimidazol Sulfonyl-chlorid Reaktionsbe- dingungen. .. -benzimidazol [%] Schmp. [°C] Lite- ratur... 

A catch and release synthesis of tetrazoles and cyclic amidines has been reported making use of solid-supported oximes [94]. When bound sulpho-nyloximes, obtained by reacting polymer supported sulfonyl chloride with oximes, were reacted with nucleophiles, tetrazoles or cychc amidines were obtained (Scheme 19). Alternatively, the use of TMS-CN affords imino nitriles, which have been used as intermediates for the preparation of indoles, 1,2,3,4-tetrahydropyridines, quinoxalines and benzimidazoles. 

Alkyl ethers of benzoin Benzil dimethyl ketal 2-Hydroxy-2-methylphenol-l-propanone 2,2-Diethoxyacetophenone 2-Benzyl-2-At, V-dimethylamino- l-(4-morpholinophenyl) butanone Halogenated acetophenone derivatives Sulfonyl chlorides of aromatic compounds Acylphosphine oxides and bis-acyl phosphine oxides Benzimidazoles... 

Benzene chloride see Chlorobenzene Benzene sulfonyl chloride bensulide Benzil (4.4 dichloro) chlorbenzilate Benzimidazole carbendazim... 

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. 

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). 

AT-substituted benzimidazoles 62 and 63 (Fig. 6) have been reported to show anti-hepatitis B virus activity, and thus several derivatives of novel benzimidazoles 62 and 63 have been prepared by Li et al. [53]. The precursor benzimidazoles readily undergo AT-substitution reactions with sulfonyl chlorides in dichloromethane using DMAP as a base, whereas methylation can... 

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>. 

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