Reaktion #975410

Reaktionsgleichung

(2S)-2-[(4R)-2,2-dimethyl-5-oxo-1,3-dioxolan-4-yl]-4-methylpentanoic acid

1-(4-methoxyphenyl)-piperazine

DIEA

DIEA

fluoro-N,N,N′,N′-tetramethylformamidinium hexafluorophosphate

diisopropyl (R)-(+)-malate

→

white powder

(5R)-5-((1S)-1-{[4-(4-methoxyphenyl)piperazin-1-yl]carbonyl}-3-methylbutyl)-2,2-dimethyl-1,3-dioxolan-4-one

Lösungsmittel

DCM

DCM

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThe reaction mixture was stirred for 1 hour
2. 2
   Sonstigeis at RT
3. 3
   SonstigePurification
4. 4
   workup.WAITwas performed with a gradient cHex/EtOAc 4:1 to c-Hex/EtOAc 1:1 in 30 min

Vorschrift

To a cold solution (0° C.) of (2S)-2-[(4R)-2,2-dimethyl-5-oxo-1,3-dioxolan-4-yl]-4-methylpentanoic acid (prepared according to WO 94/02447 or similarly to Seebach et al., 1990, Org. Syntheses, Coll. Vol. III, p 153-159 but starting from diisopropyl (R)-(+)-malate, 150 mg, 0.65 mmol) in anhydrous DCM (3 mL) were added DIEA (115 μL, 0.69 mmol) and fluoro-N,N,N′,N′-tetramethylformamidinium hexafluorophosphate (190 mg, 0.72 mmol, Aldrich). The reaction mixture was stirred at 0° C. for 40 min. Then a solution of 1-(4-methoxyphenyl)-piperazine (138 mg, 0.72 mmol, Chess) and DIEA (115 μL, 0.69 mmol) in anhydrous DCM (1 mL) was added. The reaction mixture was stirred for 1 hour is at RT and then poured on a silica column (30 g, wet with c-Hex/EtOAc 4:1). Purification was performed with a gradient cHex/EtOAc 4:1 to c-Hex/EtOAc 1:1 in 30 min to give 158 mg of a white powder. Recrystallization from iPrOH gave 112 mg (43%) of the title compound as a white powder. HPLC, Rt: 3.02 min (purity: 99.0%). LC/MS, M+(ESI): 405.3. 1H NMR (CD3OD, 300 MHz) δ 7.00 (d, J=9.2 Hz, 2H), 6.89 (d, J=9.2 Hz, 2H), 4.56 (d, J=8.7 Hz, 1H), 3.87 (m, 3H), 3.78 (s, 3H), 3.73 (m, 1H), 3.50 (m, 1H), 3.15-3.00 (m, 4H), 1.93-1.72 (m, 2H), 1.66 (s, 3H), 1.58 (m, 1H), 1.56 (s, 3H), 0.98 (d, J=6.4 Hz, 6H).

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