2,6-Lutidine → (S)-3-[4-(2,6-Dichloro-benzoylamino)-phenyl]-2-{[1-(4-methoxy-benzyl)-cyclopentanecarbonyl]-amino}-propionic acid

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Reaction Steps

4-Amino-N-[[1-[(4-methoxyphenyl)methyl]cyclopentyl]carbonyl]-L-phenylalanine methyl ester (66 mg, 0.17 mmol) and 2,6-dichlorobenzoyl chloride (50 mg, 0.23 mmol) were dissolved in 5 mL of dichloromethane and 2,6-lutidine (50 μL, 0.43 mmol) were added. After 4 hours, the mixture was diluted with ether and dichloromethane and washed with 1 N HCl, water, and saturated NaHCO3 and was dried (MgSO4). The crude product was dissolved in methanol (4 mL) and treated with 4 N NaOH (0.1 mL). After 2 hours, the excess base was quenched with acetic acid (0.1 mL), the solution was filtered through a 0.2μ nylon filter and the filtrate was purified by RP-HPLC on a 4×30 cm Rainin C-18 column using a gradient of 5 to 95% acetonitrile:water containing 0.75% trifluoroacetic acid at a flow of 49 mL/min over 35 min. The peak eluting at 79% acetonitrile was concentrated and lyophilized to give 4-[[(2,6-dichlorophenyl)carbonyl]amino]-N-[[1-[(4-methoxyphenyl)methyl]cyclopentyl]carbonyl]-L-phenylalanine (28.2 mg), HR—FABMS: obs. mass 591.1445. Calcd. mass 591.1430 (M+Na).

Provenance & Evidence