1-[(4'-Fluorobiphenyl-4-sulfonyl)-(3-hydroxypropyl)amino]-cyclopentanecarboxylic acid benzyl ester → 1-[(2-Carboxyethyl)-(4'-fluorobiphenyl-4-sulfonyl)amino]-cyclopentanecarboxylic acid benzyl ester

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Reaction Steps

A solution of the crude 1-[(4'-fluorobiphenyl-4-sulfonyl)-(3-hydroxypropyl)amino]cyclopentanecarboxylic acid benzyl ester (22.1 grams) in acetone (400 mL) was cooled in an ice bath and treated with Jones reagent (about 20 mL) until an orange color persisted. The mixture was stirred from 0° C. to room temperature over 2 hours. After quenching excess oxidant with isopropanol (1 mL), Celite™ was added and the mixture was filtered. The filtrate was concentrated under vacuum. The residue was taken up in ethyl acetate, washed with water and brine, dried over magnesium sulfate and concentrated to afford crude 1-[(2-carboxyethyl)-(4'-fluorobiphenyl-4-sulfonyl)amino]-cyclopentanecarboxylic acid benzyl ester as an oil (21.4 grams).

Provenance & Evidence