Hydrochloric Acid → HCID 67498866, compound

Participants

Reaction Steps

To 2-methyl-1-n-propylbenzimidazole-5-carboxylic acid (see Working Example 82-3) (1.0 g, 3.93 mmol) was added thionyl chloride (8 mL), and this was stirred at reflux for 3 hours. After the reaction was complete, concentration at reduced pressure gave a residue that was added to 2-aminophenol (456 mg, 2.96 mmol), triethylamine (899 mg, 8.88 mmol) and tetrahydrofuran (10 mL), and this was stirred at room temperature for 14 hours. After the reaction was complete, this was concentrated, and to a dioxane (10 mL) solution of the residue obtained was added methanesulfonic acid (1.42 g, 14.8 mmol), and this was heated to reflux for 18 hours. After the reaction solution was cooled, water and saturated aqueous sodium hydrogen carbonate were added, the precipitated crystals were filtered, washed with water and dried. To the residue obtained was added iron powder (400 mg, 7.12 mmol), 10% aqueous acetic acid (20 mL), and ethanol (20 mL), and this was heated to reflux for 2 hours. After the reaction solution was cooled, a 1N aqueous sodium hydroxide solution and chloroform were added, this was filtered through Celite, and the filtrate obtained was extracted. After the organic layer obtained was dried over anhydrous sodium sulfate, it was filtered and concentrated. The residue obtained was purified by silica gel column chromatography, and the oil obtained was dissolved in tetrahydrofuran (3 mL), and to this was added a 1M solution of hydrogen chloride in diethyl ether (1 mL). The precipitated crystals were filtered, and after washing with tetrahydrofuran, they were dried to yield the title compound (168 mg, 25% yield) as light green crystals.

Provenance & Evidence