Synthesis of 2-aminobenzimidazole

Synthesis of 2-aminobenzimidazolePreparation of 2-aminobenzimidazole

Preparation of 2-aminobenzimidazole

Preparation of 2-aminobenzimidazole

Preparation of 2-aminobenzimidazole

To a stirred solution of Aniline (1 eq.) in glacial Acetic Acid (10 mL) at 5°C, potassium thiocyanate (4 eq.) was added. The mixture was stirred at the same temperature for 1 hour and a solution of elemental Bromine (2 eq) in glacial Acetic Acid (5 mL) was then added dropwise without that the temperature of the mixture rises over 10-15°C. After the addition of the Bromine, the reaction is slowly warmed at room temperature and reacted overnight. The mixture is quenched with crushed ice and made alkaline (pH 9-10) adding dropwise a cold aqueous solution of ammonia 35%. The precipitate is collected through filtration, washed with water and recrystallized from methanol/diethyl ether affording the desired product as a pale yellow solid (95% yield).






InChI Key


Canonical SMILES


MeSH Synonyms

2-aminobenzimidazole, 2-aminobenzimidazole hydrochloride, 2-aminobenzimidazole monobenzoate, 2-aminobenzimidazole monohydrochloride, 2-aminobenzimidazole monoperchlorate, 2-aminobenzimidazole monosulfate, 2-aminobenzimidazole sulfate, 2-aminobenzimidazole sulfate (2:1), 2-aminobenzimidazole tartrate(2:1), (L)-(+)-isomer, 2-aminobenzimidazole, conjugate monoacid

Depositor-Supplied Synonyms

2-AMINOBENZIMIDAZOLE, 1H-Benzimidazol-2-amine, 934-32-7, 1H-Benzo[d]imidazol-2-amine, 2-Iminobenzimidazoline, Benzimidazol-2-ylamine, Benzimidazole, 2-amino-, 2-Amino benzimidazole, 2-Amino-1H-benzimidazole, 2-Benzimidazolamine, USAF EK-4037, Caswell No. 033AA, 1H-benzimidazol-2-ylamine, 1H-Benzoimidazol-2-ylamine, UNII-E65DE7521V, 1H-1,3-benzodiazol-2-amine, CCRIS 4354, CHEMBL305513, CHEBI:27822, JWYUFVNJZUSCSM-UHFFFAOYSA-N, NSC 7628, EINECS 213-280-6, MFCD00005596, NSC 27793, BRN 0116525, benzimidazole-2-ylamine, AI3-60094, DSSTox_CID_4465, DSSTox_RID_77410, DSSTox_GSID_24465, WLN: T56 BM DNJ CZ, 144704-99-4, CAS-934-32-7, 2fpz, benzimidazole amine, benzimidazole-amine, 2-ammobenzimidazole, CRA Fragment 9, AX7, benzimidazol-2-amine, 2-aminobenzoimidazole, zlchem 194, 2-amino-benzimidazole, PubChem9020, 2fx6, ACMC-209rlr, MET222A_SUPELCO, 1H-benzoimidazol-2-amine, Imidazole C-2 deriv. 3, AC1Q52ZU, SCHEMBL9098, Oprea1_243328, JMC524454 Compound 5, KSC488C2F, MLS001074865, 1H-benz[d]imidazole-2-amine, BIDD:GT0837, 171778_ALDRICH, 36570_RIEDEL, AC1L224I, BDBM7960, SCHEMBL2475507, SCHEMBL3350089, CTK3I8122, EBD2768, NSC7628, ZLB0185, MolPort-000-639-758, BB_SC-3294, E65DE7521V, HMS1741L08, HMS2865C12, ACT05692, NSC-7628, NSC27793, STR00452, Tox21_201949, Tox21_303120, ANW-40045, BBL033933, NSC-27793, SBB028244, STL283126, ZINC16889973, AKOS000104081, CS16315, LS-1955, MCULE-2427064128, RP20071, RTR-029264, NCGC00091178-01, NCGC00091178-02, NCGC00257027-01, NCGC00259498-01, AC-15858, AK-54965, AM804572, AN-24959, HE019504, KB-88223, SC-07373, SMR000019082, TS-01718, 1,3-dihydro-benzoimidazol-2-ylidene amine, KB-227279, ST2408889, TL8005923, TR-029264, A0850, EU-0067838, FT-0611230, ST50949412, C10901, M-6487, 49803-EP2295432A1, 49803-EP2298738A1, 49803-EP2311825A1, 5-25-10-00372 (Beilstein Handbook Reference), AQ-738/40188880, I01-0616, Q-101103, T5430950, 3B3-029414, InChI=1/C7H7N3/c8-7-9-5-3-1-2-4-6(5)10-7/h1-4H,(H3,8,9,10

Removed Synonyms

aminobenzimidazole, C7H7N3, 2H-BENZOIMIDAZOL-2-YLAMINE, CID13624, C1541

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  1. Samir Gaballah

    this experimental procedure is not for synthesizing 2-aminobenzimidazole. It is for making 2-aminobenzothiazole. To make 2-aminobenzimidazole, one should start with o-phenylenediamine and cyanogen bromide in a mixture of water and methanol.

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