Tributylphosphine → 4-{4-[2-(2,6-Dichloro-4-methylphenoxy)ethoxy]phenyl}piperidine-1,3-dicarboxylic acid 1-tert-butyl ester 3-methyl ester

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Reaktionsschritte

A mixture of compound 4-[4-(2-Hydroxyethoxy)phenyl]piperidine-1,3-dicarboxylic acid 1-tert-butyl ester 3-methyl ester (5.50 g, 15 mmol), 2,6-dichloro-p-cresol (3.08 g, 18 mmol), azodicarboxylic dipiperidine (7.31 g, 29 mmol) and PBu3 (14 mL, 58 mmol) in toluene (150 mL) was heated to 50° C. for 16 h. The mixture was allowed to cool to rt, filtered, and the precipitate was washed with toluene. The filtrate was diluted with EtOAc, and washed with water (2×) and brine. The org. layer was dried over MgSO4, filtered, and the solvents were removed under reduced pressure. Purification of the crude by FC (EtOAc/heptane 0:1→1:9→2:8) yielded the compound as a colorless oil (7.3 g, 90%). LC-MS: tR=1.18 min, ES+=538.34.

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