benzimidazole benzimidazole benzimidazole is a heterocyclic aromatic organic compound. this bicyclic compound may be viewed as fused rings of the aromatic compounds benzene and imidazole. it is a white solid that appears in form of tabular crystals. not to be confused with benznidazole. benzimidazole names preferred iupac name 1h-1,3-benzimidazole other names 1h-benzoimidazole identifiers cas number 51-17-2 y 3d model (jsmol) interactive image beilstein reference 109682 chebi chebi:41275 y chembl chembl306226 y chemspider 5593 y drugbank db02962 echa infocard 100.000.075 ec number 200-081-4 gmelin reference 3106 kegg c02009 y pubchem cid 5798 unii e24gx49ld8 y comptox dashboard (epa) dtxsid8024573 inchi inchi=1s/c7h6n2/c1-2-4-7-6(3-1)8-5-9-7/h1-5h,(h,8,9) ykey: hyzjckykohlvjf-uhfffaoysa-n yinchi=1/c7h6n2/c1-2-4-7-6(3-1)8-5-9-7/h1-5h,(h,8,9)key: hyzjckykohlvjf-uhfffaoyax smiles c1ccc2c(c1)cn2 properties chemical formula c7h6n2 molar mass 118.139 g·mol−1 melting point 170 to 172 °c (338 to 342 °f; 443 to 445 k) acidity (pka) 12.8 (for benzimidazole) and 5.6 (for the conjugate acid) hazards ghs labelling: pictograms signal word warning hazard statements h302, h315, h319, h335 precautionary statements p261, p264, p270, p271, p280, p301+p312, p302+p352, p304+p340, p305+p351+p338, p312, p321, p330, p332+p313, p337+p313, p362, p403+p233, p405, p501 safety data sheet (sds) external msds except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). y verify (what is yn ?) infobox references preparation benzimidazole is produced by condensation of o-phenylenediamine with formic acid, c6h4(nh2)2 + hc(och3)3 → c6h4n(nh)ch + 3 ch3oh 2-substituted derivatives are obtained when the condensation is conducted with aldehydes in place of formic acid, followed by oxidation. reactions benzimidazole is a base: c6h4n(nh)ch + h+ → + it can also be deprotonated with stronger bases: c6h4n(nh)ch + lih → li + h2 the imine can be alkylated and also serves as a ligand in coordination chemistry. the most prominent benzimidazole complex features n-ribosyl-dimethylbenzimidazole as found in vitamin b12. n,n'-dialkylbenzimidazolium salts are precursors to certain n-heterocyclic carbenes. applications benomyl is a fungicide with a benzimidazole core benzimidazole derivatives are among the most frequently used ring systems for small molecule drugs listed by the united states food and drug administration. many pharmaceutical agents belong to the benzimidazole class of compounds. for example: angiotensin ii receptor blockers such as azilsartan, candesartan, and telmisartan. anthelmintic agents such as albendazole, ciclobendazole, fenbendazole, flubendazole, mebendazole, oxfendazole, oxibendazole, triclabendazole, and thiabendazole. antihistamines such as astemizole, bilastine, clemizole, emedastine, mizolastine, and oxatomide. benzimidazole fungicides such as benomyl, carbendazim, fuberidazole, and thiabendazole. benzimidazole opioids such as bezitramide, brorphine, clonitazene, etodesnitazene, etonitazene, etonitazepipne, etonitazepyne, isotonitazene, metodesnitazene, and metonitazene. proton-pump inhibitors such as dexlansoprazole, esomeprazole, ilaprazole, lansoprazole, omeprazole, pantoprazole, rabeprazole, and tenatoprazole. typical antipsychotics such as benperidol, clopimozide, droperidol, neflumozide, and oxiperomide, and pimozide. other notable pharmaceutical agents which contain a benzimidazole group include abemaciclib, bendamustine, dabigatran, daridorexant, and glasdegib. in printed circuit board manufacturing, benzimidazole can be used as an organic solderability preservative. several dyes are derived from benzimidazoles.