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Preparation of (S)-2-[(S)-(2,3,4,5,6-pentafluorophenoxy)phenoxy phosphorylamino] propionic acid isopropyl ester

IP.com Disclosure Number: IPCOM000244768D
Publication Date: 2016-Jan-12
Document File: 1 page(s) / 31K

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Abstract

process for the preparation of (S)-2-[(S)-(2,3,4,5,6-pentafluorophenoxy) phenoxy phosphorylamino] propionic acid isopropyl ester

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Preparation of (S)-2-[(S)-(2,3,4,5,6-pentafluorophenoxy)phenoxy phosphorylamino] propionic acid isopropyl ester

wherein X is halogen selected from fluorine, chlorine, bromine and iodine.

Preparation of (S)-2-[(S)-(2,3,4,5,6-pentafluorophenoxy)phenoxy phosphorylamino] propionic acid isopropyl ester

Under nitrogen atmosphere, L-alanine isopropyl ester (65.3 g) and trimethylamine (57.55 g) were added sequentially and slowly to a solution of Phenyl dichlorophosphate (100 g) in methylene dichloride (500 mL) at -18 °C to -15°C. Obtained reaction mass was stirred at -18 °C to -15 °C for 3-4 hours. Thereafter, Pentafluorophenol (87.2 g) in methylene dichloride (300 mL) and trimethylamine (57.55 g) were added sequentially and slowly. Stirring was continued to complete the reaction.  Thereafter, the reaction mass temperature was raised slowly to 0-5 °C and diluted with water (500 mL). After adjusting the pH to 1.5-2.0 with diluted hydrochloric acid, organic layer was separated and aqueous layer was extracted with methylene dichloride. Combined organic layer was washed with water, concentrated under reduced pressure at 40-45 °C and traces of methylene chloride were removed with methyl tert-butyl ether. Thus obtained, residue was diluted with methyl tert-butyl ether (300 mL), temperature raised to 40-45 °C and stirred for 30-40 minutes. Thereafter, the slurry mass was cooled to 0-5 °C and stirred for 6 hours. The obtained product was filtered, washed with pre cooled methyl tert...