Cuminaldehyde → 4-(4-isopropylphenyl)-4,5,6,7-tetrahydro-3H-imidazo[4,5-c]pyridine

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Reaction Steps

A mixture of histamine dihydrochloride (1.85 g, 10.0 mmol), water (10 mL), potassium hydroxide (1.72 g, 30.0 mmol), ethanol (25 mL) and 4-isopropylbenzaldehyde (1.62 g, 10.91 mmol) was heated to reflux for 1.5 h. Ethanol was evaporated and the residue was diluted with water (40 mL). Extraction (5×25 mL DCM), washing of the combined extracts (2×50 mL brine) and drying (MgSO4) yielded 2.29 g (87%) of crude 4-(4-isopropylphenyl)-4,5,6,7-tetrahydro-imidazo[4,5-c]pyridine, which was used for the next synthetic step without further purification. This amine (0.48 g, 1.99 mmol) was dissolved in DCM (5 mL) and added to a 30 min old mixture of 3-(4-fluorophenyl)propionic acid (0.31 g, 1.84 mmol), HOBt (0.27 g, 1.20 mmol) and EDC (0.42 g, 12.19 mmol) in DCM (10 mL). After 18 h the mixture was washed with water (50 mL), dried (MgSO4) and concentrated. The crude product was purified by column chromatography (silica gel, gradient elution with DCM/methanol). 0.24 g (33%) of the title amide was obtained.

Provenance & Evidence