Diphenylacetic Acid → (S)-5-diphenylacetyl-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid methyl ester

Acetonitrile (16 ml) was added to a mixture of N,N'-dicyclohexylcarbodiimide (DCCI) (2.1080 g, 0.01022 mol), 1-hydroxybenzotriazole (HBTA) (1.3806 g, 0.01022 mol), and diphenylacetic acid (2.1685 g, 0.01022 mol), followed by stirring at room temperature for 20 minutes. A solution of (S)-1-(3-methyl-4-nitrophenyl)methyl-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid methyl ester (VI-2) (2.7000 g, 0.00817 mol) in acetonitrile (14 ml) was added to the suspension, and the mixture was stirred at room temperature for 21 hours. An insoluble portion in the reaction mixture was filtered out and washed with acetonitrile, and then the filtrate and washings were joined and concentrated. The residue was dissolved in methylene chloride (40 ml), washed with a 10% sodium carbonate solution and a saturated brine, then dried over sodium sulfate and concentrated to obtain an orange oily material (4.5203 g). This crude oily material was purified by silica gel column chromatography (Kieselgel 60, 270 g, chloroform/methanol=60/11) to obtain the objective compound (V-2) (2.8250 g; yield: 65.9%) as colorless crystals (top: 174.5°-177° C.).

1. stirringthe mixture was stirred at room temperature for 21 hours
2. filtrationAn insoluble portion in the reaction mixture was filtered out
3. washwashed with acetonitrile
4. concentrationconcentrated
5. dissolutionThe residue was dissolved in methylene chloride (40 ml)
6. washwashed with a 10% sodium carbonate solution
7. dry with materiala saturated brine, then dried over sodium sulfate
8. concentrationconcentrated

ORD record

ord-6cea3f30e7a94340a0738226bb8f42f8

Source dataset

uspto-grants-1995_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05401736