Reaktion #554572

Reaktionsgleichung

NaOH

15a

Methyl 6-trityloxy-hexanoate

NaOH

→

white powder 16a

Ausbeute 78.1%

6-Trityloxyhexanoic acid

Ausbeute 78.1%

Lösungsmittel

THF

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGstirring
2. 2
   workup.WAITwas continued for another 2 days
3. 3
   SonstigeThe THF was removed under reduced pressure
4. 4
   Extraktionextracted with diethyl ether
5. 5
   WaschenThe combined organic layers were washed with brine
6. 6
   Trocknendried over MgSO4
7. 7
   SonstigeThe diethyl ether was removed under reduced pressure
8. 8
   Sonstigethe resulting crude powder was recrystalized in hexanes

Vorschrift

An aqueous solution of 5 M NaOH (17.5 mL, 87.5 mmol) was added to a stirring solution of 15a (20.1 g, 51.6 mmol) in 130 mL of THF and 52.5 mL of water at room temperature. After stirring for 2 days, 3.1 mL of 5 M NaOH (15.5 mmol) was added, and stirring was continued for another 2 days. The THF was removed under reduced pressure, then the aqueous residue was acidified with 1 M HCl to pH 5 and extracted with diethyl ether. The combined organic layers were washed with brine and dried over MgSO4. The diethyl ether was removed under reduced pressure, and the resulting crude powder was recrystalized in hexanes to yield 15.1 g (78%) of white powder 16a. Mp 114-116° C. 1H-NMR (400 MHz, CDCl3, δH ppm): 7.43 (6H, m, p-Ar), 7.28 (6H, m, m-Ar), 7.22 (3H, m, o-Ar), 3.05 (2H, t, 3JH—H=6.4 Hz, HO—CH2), 2.33 (2H, t, 3JH—H=7.5 Hz, CH2CO2), 1.56-1.68 (4H, m, 2CH2), 1.36-1.47 (2H, m, CH2). 13C-NMR (100 MHz, CDCl3, δH ppm): 180.26, 144.36, 128.62, 127.66, 126.79, 86.30, 63.24, 33.98, 29.63, 25.74, 24.48. HRMS (EI): m/z calcd 374.1882 (C25H26O3), found 374.1883 [M]+.

Quelle