Ethyl 1H-benzimidazole-6-carboxylate → 5-(Hydroxymethyl)-1H-benzimidazole

HRID 465039

Reaction equation

HRID 465039 reaction equation
C([O:3][C:4]([C:6]1[CH:14]=[CH:13][C:9]2[N:10]=[CH:11][NH:12][C:8]=2[CH:7]=1)=O)C.[H-].[Al+3].[Li+].[H-].[H-].[H-]>O1CCCC1>[OH:3][CH2:4][C:6]1[CH:14]=[CH:13][C:9]2[N:10]=[CH:11][NH:12][C:8]=2[CH:7]=1

Participants

4

Reactant 2

HCID 13505555Ethyl 1H-benzimidazole-6-carboxylateHCID 21226445Aluminium lithium hydride

Product 1

HCID 135055565-(Hydroxymethyl)-1H-benzimidazoleYield 62%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

According to a method similar to that described in Zhur. Obschei Khim., vol. 32, pp 835-41 (1953), 3,4-diaminobenzoic acid was prepared. A formic acid solution (200 ml) of 3,4-diaminobenzoic acid (8 g) thus prepared was refluxed for 4 hrs to yield 5-carboxybenzimidazole.hydrochloride (8.9 g). The carboxylic acid (8.9 g) was refluxed with heating for 3.5 hrs in a mixture of sulfuric acid (4 ml) and absolute ethanol (140 ml) to yield 5-ethoxycarbonylbenzimidazole (mp. 93°-94° C., 7.8 g). An anhydrous tetrahydrofuran solution (20 ml) of the ester (7.5 g) was added to an anhydrous tetrahydrofuran suspension (50 ml) of lithium aluminium hydride (6.5 g) while cooling. The mixture was stirred for 3 hrs at room temperature to yield 5-hydroxymethylbenzimidazole (mp. 128.4° C., 3.62 g). A 47% aqueous hydrobromic acid solution (33 ml) containing the benzimidazole derivative (2.2 g) and cysteamine hydrochloride (1.9 g) was refluxed with heating for 7 hrs to yield 5-[(2-aminoethyl)thiomethyl]benzimidazole.2 hydrobromide (mp. 224°-225° C., 4.2 g).

Workup

  1. temperaturewhile cooling

Sources & evidence

ORD record
ord-74ae9b1a2ca648fb8ea828081fade12f
Source dataset
uspto-grants-1985_10
Patent number
US04550118

Linked notes

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