Imidazole → 5-t-Butyldiphenylsilyloxy-4-(R)-iodopentanoic acid, methyl ester

HRID 653976Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 653976
[Si:1]([O:18][CH2:19][C@@H:20](O)[CH2:21][CH2:22][C:23]([O:25][CH3:26])=[O:24])([C:14]([CH3:17])([CH3:16])[CH3:15])([C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N1C=CN=C1.[I:52]I>C1(C)C=CC=CC=1>[Si:1]([O:18][CH2:19][C@H:20]([I:52])[CH2:21][CH2:22][C:23]([O:25][CH3:26])=[O:24])([C:14]([CH3:17])([CH3:16])[CH3:15])([C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Komponenten

6

Edukt 4

HCID 795ImidazoleHCID 807IodineHCID 11776TriphenylphosphineHCID 110254905-t-Butyldiphenylsilyloxy-4-(S)-hydroxypentanoic acid, methyl ester

Produkt 1

HCID 151260955-t-Butyldiphenylsilyloxy-4-(R)-iodopentanoic acid, methyl ester

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 1140TolueneLösungsmittel

Versuchsvorschrift

To a solution of 7 (4.33 g, 11.2 mmol) in 250 mL toluene was added triphenylphosphine (5.9 g, 22.4 mmol), imidazole (2.3 g, 33.6 mmol), and iodine (4.26 g, 16.8 mmol) under a nitrogen atmosphere. The reaction mixture was lowered into a preheated heating mantle and refluxed for 1 hour. The reaction mixture was quenched by pouring into 200 mL saturated NaHCO3 solution. Excess triphenylphosphine was destroyed by the addition of iodine until an iodine coloration remained in the organic phase. The organic phase was then washed with 5% sodium thiosulfate solution (2×100 mL) and 2×200 mL water. The product was purified by flash chromatography with 6:1 hexane/ethyl acetate yield 4.75 g (85%) of a viscous oil; [α]D25 +6.5° (C=1, CHCl3); FAB MS 497 (M+H)+, 439 (M-t-butyl)+ ; 1H NMR (CDCl3) δ 7.89 (m, 4, ArH), 7.4 (m, 6, ArH), 4.15 (m, 1, H-4), 3.85 (m, 2, CH ), 3.7 (s, 3, OCH3), 2.5 (m, 2, CH2), 2.25 (m, 1, H-2), 2.1 (m, 1, H-2), 1.1 (s, 9, t-butyl).

Aufarbeitung

  1. temperaturerefluxed for 1 hour
  2. customThe reaction mixture was quenched
  3. additionby pouring into 200 mL saturated NaHCO3 solution
  4. customExcess triphenylphosphine was destroyed by the addition of iodine until an iodine coloration
  5. washThe organic phase was then washed with 5% sodium thiosulfate solution (2×100 mL) and 2×200 mL water
  6. customThe product was purified by flash chromatography with 6:1 hexane/ethyl acetate yield 4.75 g (85%) of a viscous oil

Quellen und Nachweise

ORD-Eintrag
ord-ec4dabde2d3f4a60b31f814b5b5c2c7c
Quelldatensatz
uspto-grants-1992_07
Patentnummer
US05128458

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