2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → HCID 67193678, compound

Participants

Reaction Conditions

Reaction Steps

A solution of H-His-(Bzl)-OH (2.0 g, 8.16 mmol) and formaldehyde (37% in water, 0.92 ml, 12.24 mmol) in water (16 ml) was heated to reflux for 4 hours and concentrated to dryness. The residue was dissolved in methanol (4.6 ml) cooled to 0° C. and treated with thionyl chloride (0.6 ml, 8.12 mmol). The reaction mixture was reflux for 2.5 hours and concentrated. The solid was dissolved in dichloromethane, washed with a saturated solution of sodium hydrogenocarbonate, brine, dried over sodium sulfate and concentrated to dryness to yield 1-Benzyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid methyl ester (1.58 g, 71%). The ester was dissolved in tetrahydrofuran (26 ml), cooled to 0° C. and treated with 2,3-Dichloro-5,6-dicyanobenzoquinone (2.9 g, 12.81 mmol) in tetrahydrofuran (26 ml) and the reaction mixture was reflux for 4 hours. The solvent was removed and the black residue was dissolved in dichloromethane and treated with a 1M aqueous solution of sodium hydroxide. The aqueous solution was extracted several times with dichloromethane. The combined organic extracts were washed with brine, dried over sodium sulfate, concentrated and purified by flash chromatography over silica gel (gradient ethyl acetate/methanol: 0-10%) to yield 1-Benzyl-1H-imidazo[4,5-c]pyridin-6-carboxylic acid methyl ester (525 mg, 34%) as a beige solid.

Provenance & Evidence