Iodine → HCID 131713230, compound

Participants

Reaction Steps

A solution of cyclopentanecarboxylic acid (0.26 g., 0.0023 mole) and 1-hydroxybenzotriazole hydrate (0.31 g., 0.0023 mole) in tetrahydrofuran (10 ml.) is cooled to 0°, followed by the portionwise addition of N,N-dicyclohexylcarbodiimide (0.47 g., 0.0023 mole). The bath is removed and the mixture is stirred at ambient temperature for 70 minutes. After filtration, the mixture is concentrated in vacuo. To the residue, dissolved in dimethylformamide (8 ml.) plus tetrahydrofuran (10 ml.), is added a solution of (±)-1-[[[1-(amino)-3-phenylpropyl]ethoxyphosphinyl]acetyl]-L-proline, 1,1-dimethylethyl ester (1 g., 0.0023 mole), prepared for example as described in Example 85 (d), and triethylamine (0.25 g., 0.0025 mole) in dimethylformamide (10 ml.). The mixture is stirred at ambient temperature for 16 hours. It is then concentrated in vacuo and the residue is dissolved in ethyl acetate (75 ml.), washed with water, 10% citric acid, saturated sodium bicarbonate, brine, and dried (MgSO4). The solvent is removed in vacuo to give 1.2 g. of an amber oil residue. It is chromatographed on silica gel, eluted with dichloromethane, dichloromethane/acetone (4:1) to give 1.1 g. of (±)-1-[[[[1-(cyclopentylcarbonyl)amino]-3-phenylpropyl]ethoxyphosphinyl]acetyl]-L-proline, 1,1-dimethylethyl ester as an oil in two fractions: 0.8 g., Tlc, silica gel, acetone, shows a single spot at Rf 0.55; and 0.3 g., Tlc, shows two spots, Rf 0.55 and Rf 0.52 (visualized with PMA plus heat, or I2 vapor).

Provenance & Evidence